HomeMy WebLinkAbout2022-09-27; City Council; ; Authorize City and Carlsbad Municipal Water District Support for the Encina Wastewater Authority’s One Water North San Diego County Water Reuse StudiesCA Review _RMC_
Meeting Date:
To:
From:
Staff Contact:
Subject:
Districts:
Sept. 27, 2022
Mayor and City Council/President and Board Members
Scott Chadwick, City Manager/Executive Manager
Vicki Quiram, Utilities Director
vicki.quiram@carlsbadca.gov, 442-339-2722
Authorize City and Carlsbad Municipal Water District Support for the
Encina Wastewater Authority’s One Water North San Diego County
Water Reuse Studies
All
Recommended Actions
1.Receive a report from Encina Wastewater Authority General Manager Scott McClelland
on “One Water North San Diego County,” a potable water reuse project being studied
by the wastewater authority
2.Adopt resolutions authorizing the City Manager/Executive Manager to sign the
principles of understanding document, committing the city and the Carlsbad Municipal
Water District to be advocacy agencies of the One Water North San Diego County water
reuse project for 2022-23
Executive Summary
In June 2021, Mayor Pro Tem Keith Blackburn requested a presentation by the Encina
Wastewater Authority to update the City Council on its developing innovative projects.
With the scarcity of potable water in Southern California, the Encina Wastewater Authority with
its member agencies, including the City of Carlsbad, have been studying the potential of reusing
the portion of effluent from its wastewater treatment plant that is treated and still discharged
to the ocean. This project, called One Water North San Diego County, would further improve
the quality of the water through an advanced treatment process so that it could be used for
local potable water supply.
Encina Wastewater Authority staff will give the City Council a presentation on the following
topics:
•Outcomes of its 2018 Potable Water Reuse Feasibility Study
•Update on EWA’s One Water North County water reuse project and pilot study
•Upcoming Potable Reuse Strategic Plan
•Information on becoming an advocacy agency for the project
Sept. 27, 2022 Item #10 Page 1 of 279
A regional approach to this future potable reuse project represents the best opportunity for
success. Encina Wastewater Authority is asking interested agencies to sign a principles of
understanding document to become advocacy agencies for the project. This document is
intended to establish a framework for the wastewater authority activities through 2022-23 and
set expectations for those agencies willing to advocate for the project, and to participate in
future project phases.
There are no financial commitments associated with this agreement.
Discussion
Background
The City of Carlsbad provides wastewater collection service to 74% of the city through six
interceptor pipelines, 265 miles of collection and conveyance pipelines, 6,000 manholes and 11
lift stations. All wastewater flows to the Encina Water Pollution Control Facility for treatment.
Treated wastewater is disposed through the ocean outfall pipe or sent to the Carlsbad Water
Recycling Facility for additional treatment and reuse as recycled water by the Carlsbad
Municipal Water District, which provides water and recycled water to approximately 82% of the
city.
The Encina Water Pollution Control Facility is governed by a joint powers authority, the Encina
Wastewater Authority. The joint powers authority is made up of six north San Diego County
public agencies, including the city. (The other member agencies are the cities of Encinitas and
Vista, the Buena Sanitation District, Vallecitos Water District and Leucadia Wastewater District.
The authority is governed by a 10-member board consisting of council members or directors
from the member agencies. The city holds two seats on the Encina Wastewater Authority Board
of Directors, with Mayor Pro Tem Blackburn and Councilmember Acosta currently serving in
those roles. Mayor Pro Tem Blackburn also serves on the board’s newly established Water
Reuse Executive Steering Committee.
The first phase of CMWD’s recycled water program began in 1994. Today, 22% of the water
that the district serves to its customers is recycled water. This water goes through advanced
treatment at the Carlsbad Water Recycling Facility and is delivered to customers for irrigation
and some light industrial use. CMWD’s water recycling reduces the amount of treated
wastewater the Encina Wastewater Authority must discharge to the ocean and offsets the use
of potable water in the CMWD service area. The One Water North San Diego County project
would have no effect on CMWD’s production or distribution of recycled water.
One Water North San Diego County – water reuse project
With the severity of the current long-term drought and the scarcity of potable water in
California, it is more important than ever to not only provide safe and reliable potable water
service but also to develop local reliable and renewable water supplies. The wastewater
authority and its member agencies have one of the largest untapped local water supplies in the
region: the treated wastewater now being discharged into the sea.
The Encina Wastewater Authority not only has access to this water, it has land available for the
site of an advanced wastewater treatment facility and staff with the expertise needed to
implement and operate one.
Sept. 27, 2022 Item #10 Page 2 of 279
Although there are considerations that need more analysis, this water reuse project could
provide a significant local supply of water for Carlsbad and surrounding cities. This resource also
has the potential to provide greater local control of the cost of water and may be cost
competitive with water imported from elsewhere.
The estimated potable water demand from the currently interested participating agencies in
the year 2035 totals 18,500 acre feet1 per year. This demand closely matches the potential
supply available from the Encina Wastewater Authority of 20,000 acre feet per year. CMWD
estimates that it may use up to 3,500 acre-feet per year in potable reuse local supply water if
the project is economically feasible and comes to fruition.
This reuse project would require an even more advanced treatment facility than the Encina
Pollution Control Facility and Carlsbad’s Water Recycling Facility. The discussion among the
authority and its member agencies became more robust a few years ago when state legislation
was introduced that would have required wastewater treatment plants to eliminate all
discharges to the ocean. Although the legislation was not successful, similar proposals will likely
reappear in the future.
The “One Water North San Diego County” water reuse project was included as a conceptual
project in both the Carlsbad Municipal Water District and the San Diego County Water
Authority’s 2020 Urban Water Management Plans for a new water supply in 2035. However,
because the project is still considered conceptual, the additional water supply amounts are not
included in the 2020 plans as future local supply.
In April 2018, the first Water Reuse Feasibility Study was presented to the Encina Wastewater
Authority Board of Directors (Exhibit 3). The study identified high-level options for potable
reuse and recycled water, or non-potable, projects to ensure year-round beneficial use of the
effluent from the Encina Water Pollution Control Facility, which is currently discharged through
the ocean outfall pipe.
Member agency staff, including City of Carlsbad staff, have continued to work with wastewater
authority staff on the potable water reuse concept and have met with potential project
partners to discuss high-level concepts. The parties that have currently expressed interest in
receiving potable water from such a project are CMWD, Olivenhain Municipal Water District,
San Dieguito Water District, Vallecitos Water District and the City of Poway. Others may
become interested as more details on the feasibility and cost of the project become available.
Proposed Advocacy Agreement
The Encina Wastewater Authority recently began asking interested agencies to sign a principles
of understanding document to become an advocacy agency for the project. The principles of
understanding define the role of an advocacy agency as follows:
• Cooperate with Encina Wastewater Authority in refining project concepts and costs
• Review and provide feedback on any documentation produced by Encina Wastewater
Authority for distribution
• Advocate for the project and solicit additional regional partners, both wholesale and
retail
1 An acre foot is the amount of water it takes to submerge one acre of land one foot deep. An average California
household uses between one-half and one acre-foot of water per year for indoor and outdoor use.
Sept. 27, 2022 Item #10 Page 3 of 279
• Participate in stakeholder meetings to discuss project concepts, regulatory issues and
funding strategies
• Participate in pursuit of funding opportunities
• Engage with regional stakeholders regarding potential institutional arrangements
• Consider financial participation in future phases of the project
With City Council and CMWD Board approval, the City Manager/CMWD Executive Manager will
be authorized to sign the documents on behalf of the city and CMWD.
Strategic planning
On May 5, 2021, the Encina Wastewater Authority Board voted unanimously to move the
potable water reuse project into the strategic planning phase, approving the following
recommendations:
1. Direct staff to develop the Water Reuse Strategic Plan
2. Direct staff to initiate pilot testing efforts with Trussell Technologies to develop
treatment technologies for wastewater so it can be reused
3. Direct staff to continue to advance the One Water North San Diego County project
4. Discuss and take other action as appropriate
The Water Reuse Strategic Plan will include:
• A funding strategy
• Partner outreach and development of the One Water North San Diego County project
• A regulatory strategy
• Refined needs and approach to Encina Water Pollution Control Facility improvements
The Water Use Strategic Plan is expected to be complete by 2024.
Options
Staff recommend the City Council and the Board of Directors authorize the city and the CMWD,
respectively, to each be a signatory to the principles of understanding document, thereby
becoming advocacy agencies of the water reuse project. The city and the CMWD will incur no
financial commitments by signing this document.
If the city and the CMWD’s project advocacy for this project is not authorized, regional
conversations will continue about the future of water reuse and local supply within the city’s
jurisdiction, but the City of Carlsbad and the CMWD will not have as strong a voice in those
discussions.
Staff have identified no drawbacks to becoming an advocacy agency.
Fiscal Analysis
No additional appropriations in fiscal year 2022-23 are being requested at this time. Potential
future fiscal year impacts will be incorporated into future budgets. Estimated Encina
Wastewater Authority costs related to the Water Use Strategic Plan are included in the
wastewater rate-setting process, which is based on budgeted wastewater authority amounts.
The wastewater authority costs are allocated and paid for by the city based on a percentage
share of ownership, which is approximately 24%.
Sept. 27, 2022 Item #10 Page 4 of 279
Next Steps
With City Council and CMWD Board approval, staff will continue to participate in Encina
Wastewater Authority’s exploration of the One Water North San Diego County and will support
the efforts outlined in the principles of understanding as an advocacy agency. Staff will return
to the City Council and the CMWD Board upon completion of the Water Reuse Strategic Plan.
Environmental Evaluation
This action does not constitute a project within the meaning of the California Environmental
Quality Act under California Public Resources Code Section 21065. It has no potential to cause
either a direct physical change in the environment or a reasonably foreseeable indirect physical
change in the environment.
Public Notification
This item was noticed in keeping with the Ralph M. Brown Act and it was available for public
viewing and review at least 72 hours before the scheduled meeting date.
Exhibits
1.City Council resolution
2.CMWD Board resolution
3.Water Reuse Feasibility Study
Sept. 27, 2022 Item #10 Page 5 of 279
RESOLUTION NO. 2022-228
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF CARLSBAD,
CALIFORNIA, AUTHORIZING THE CITY MANAGER TO SIGN THE PRINCIPLES
OF UNDERSTANDING DOCUMENT COMMITTING THE CITY TO BE AN
ADVOCACY AGENCY OF THE ONE WATER NORTH SAN DIEGO COUNTY
WATER REUSE PROJECT FOR 2022-2023
WHEREAS, the State of California and the western United States are presently experiencing an
unprecedented drought; and
WHEREAS, conservation of current water supplies and minimization of the effects of water
supply shortages that are the result of drought are essential to the public health, safety and welfare;
and
WHEREAS, support of projects that develop more local renewable water sources further these
public health, safety, and welfare interests; and
WHEREAS, the City Council of the City of Carlsbad, California has determined it necessary and
in the public interest to cooperate with the Encina Wastewater Authority in refining project concepts
and costs for the One Water North San Diego County Project, or Project; and
WHEREAS, the City of Carlsbad wishes to be an advocacy agency for the Project as described in
the Principles of Understanding for Advocacy Agency.
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Carlsbad, California, as
follows:
1.That the above recitations are true and correct.
2.That the City of Carlsbad will be a signatory to the Principles of Understanding for
Advocate Agency, attached hereto as Attachment A.
3.That the City Manager is authorized to sign the Principles of Understanding for Advocacy
Agency on behalf of the City of Carlsbad.
Exhibit 1
Sept. 27, 2022 Item #10 Page 6 of 279
PASSED, APPROVED AND ADOPTED at a Regular Meeting of the City Council of the City of
Carlsbad on the 27th day of September, 2022, by the following vote, to wit:
AYES:
NAYS:
ABSENT:
Hall, Blackburn, Bhat-Patel, Acosta, Norby.
None.
None.
MATT HA[L, Mayor
fJvC Af'--'FAVIOLA MEDINA, City Clerk Services Manager
. Y. (SEAL)
Sept. 27, 2022 Item #10 Page 7 of 279
BACKGROUND
ENCINA WASTEWATER AUTHORITY
ONE WATER NORTH SAN DIEGO
PRINCIPLES OF UNDERSTANDING
ADVOCACY AGENCY
March 2022
Attachment A
The wastewater flows and facilities at the Encina Water Pollution Control Facility (EWPCF) represents a unique
opportunity for large-scale production of purified water. EWPCF is estimated to produce approximately 20,000 acre-
feet per year of purified water for potable reuse in North San Diego County. Key assets available at the EWPCF site to
support a potable reuse project include an ocean outfall, available land for advanced treatment facility, treated
secondary effluent, and technically capable staff. A regional approach to this future potable reuse project represents
the best opportunity for success.
The purpose of this Principles of Understanding is to establish a framework for activities through 2022 -2023 and set
expectations for those agencies that are willing to advocate for the project and would likely desire to participate in future
phases of the project.
BENEFITS OF PROJECT
Wastewater Benefits
• Embraces Encina Wastewater Authority (EWA) Core Mission and Values
• Reduced ocean discharges
• Position for future treatment requirements (potential avoided costs flow and nutrients)
• Consistent with goals and commitments of Climate Change Action Plans
Water Supply Benefits
• Increase water supply reliability (locally controlled source)
• Addresses sustainability and resiliency objectives of local agencies
• Environmental and Political benefits from reduced ocean discharges
• Address future water efficiency regulations
• Reduced staffing for Advanced Treatment
• Cost competitive compared with imported water
• Further reduce Metropolitan Water District purchases
ROLE OF ADVOCACY AGENCY
Role of Advocacy Agency during 2022 -2023
• Cooperate with EWA in refining project concepts and costs
• Review and provide input on any documentation produced by EWA for distribution
• Advocate for the project and solicit additional regional partners (wholesale and retail)
• Participate in stakeholder meetings to discuss project concepts, regulatory, and funding strategies
Participate in pursuit of funding opportunities
Engage with regional stakeholders regarding potential institutional arrangements
Consider financial participation in future phases of the project
Advocate Agency
Scott Chadwick, City Manager, City of Carlsbad
Sept. 27, 2022 ONE WATER NORTH SAN DIEGO
Encina Wastewater Authority (22-14954a)
Date
Item #10 Page 8 of 279
RESOLUTION NO. 1684
A RESOLUTION OF THE BOARD OF DIRECTORS OF THE CARLSBAD
MUNICIPAL WATER DISTRICT, AUTHORIZING THE EXECUTIVE MANAGER TO
SIGN THE PRINCIPLES OF UNDERSTANDING DOCUMENT COMMITTING THE
DISTRICT TO BE AN ADVOCACY AGENCY OF THE ONE WATER NORTH SAN
DIEGO COUNTY WATER REUSE PROJECT FOR 2022-2023
WHEREAS, the State of California and the western United States are presently experiencing an
unprecedented drought; and
WHEREAS, conservation of current water supplies and minimization of the effects of water
supply shortages that are the result of drought are essential to the public health, safety and welfare;
and
WHEREAS, support of projects that develop more local renewable water sources further these
public health, safety, and welfare interests; and
WHEREAS, the Carlsbad Municipal Water District, or CMWD, Board of Directors have
determined it necessary and in the public interest to cooperate with the Encina Wastewater Authority
in refining project concepts and costs for the One Water North San Diego County Project, or Project;
and
WHEREAS, the CMWD wishes to be an advocacy agency for the Project as described in the
Principles of Understanding for Advocacy Agency.
NOW, THEREFORE, BE IT RESOLVED by the Carlsbad Municipal Water District Board of the City
of Carlsbad, California, as follows:
1.That the above recitations are true and correct.
2.That the CMWD will be a signatory to the Principles of Understanding for Advocacy
Agency, attached hereto as Attachment A.
3.That the Executive Manager is authorized to sign the Principles of Understanding for
Advocacy Agency on behalf of the CMWD.
Exhibit 2
Sept. 27, 2022 Item #10 Page 9 of 279
PASSED, APPROVED AND ADOPTED at a Regular Meeting of the Board of Directors of the
Carlsbad Municipal Water District on the 27th day of September, 2022, by the following vote, to wit:
AYES:
NAYS:
ABSENT:
Hall, Blackburn, Bhat-Patel, Acosta, Norby.
None.
None.
MATT 1tb{/!(L
k1M/ --fovFAVIOLA MEDINA, City Clerk Services Manager
(SEAL)
Sept. 27, 2022 Item #10 Page 10 of 279
BACKGROUND
ENCINA WASTEWATER AUTHORITY
ONE WATER NORTH SAN DIEGO
PRINCIPLES OF UNDERSTANDING
ADVOCACY AGENCY
March 2022
Attachment A
The wastewater flows and facilities at the Encina Water Pollution Control Facility (EWPCF) represents a unique
opportunity for large-scale production of purified water. EWPCF is estimated to produce approximately 20,000 acre-
feet per year of purified water for potable reuse in North San Diego County. Key assets available at the EWPCF site to
support a potable reuse project include an ocean outfall, available land for advanced treatment facility, treated
secondary effluent, and technically capable staff. A regional approach to this future potable reuse project represents
the best opportunity for success.
The purpose of this Principles of Understanding is to establish a framework for activities through 2022 -2023 and set
expectations for those agencies that are willing to advocate for the project and would likely desire to participate in future
phases of the project.
BENEFITS OF PROJECT
Wastewater Benefits
• Embraces Encina Wastewater Authority (EWA) Core Mission and Values
• Reduced ocean discharges
• Position for future treatment requirements (potential avoided costs flow and nutrients)
• Consistent with goals and commitments of Climate Change Action Plans
Water Supply Benefits
• Increase water supply reliability (locally controlled source)
• Addresses sustainability and resiliency objectives of local agencies
• Environmental and Political benefits from reduced ocean discharges
• Address future water efficiency regulations
• Reduced staffing for Advanced Treatment
• Cost competitive compared with imported water
• Further reduce Metropolitan Water District purchases
ROLE OF ADVOCACY AGENCY
Role of Advocacy Agency during 2022 -2023
Cooperate with EWA in refining project concepts and costs
Review and provide input on any documentation produced by EWA for distribution
Advocate for the project and solicit additional regional partners (wholesale and retail)
Participate in stakeholder meetings to discuss project concepts, regulatory, and funding strategies
Participate in pursuit of funding opportunities
Engage with regional stakeholders regarding potential institutional arrangements
Consider financial participation in future phases of the project
~~'l!tigency
Scott Chadwick, Executive Manager, Carlsbad Municipal Water District
Sept. 27, 2022 ONE WATER NORTH SAN DIEGO
Encina Wastewater Authority (22-14954a)
Date
Item #10 Page 11 of 279
Encina Wastewater Authority
WATER REUSE FEASIBILITY STUDY
Final Report | July 2018
Prepared by Woodard & Curran
In Association with:
Carollo Engineers | Trussell Technologies Inc.
Ken Weinberg Water Resources Consulting, LLC | Michael R. Welch, Ph.D., P.E.
Exhibit 3
Sept. 27, 2022 Item #10 Page 12 of 279
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Sept. 27, 2022 Item #10 Page 13 of 279
EWA Water Reuse Feasibility Study
Final Report
Prepared by:
In Association with:
Trussell Technologies Inc.
Carollo Engineers Inc.
Ken Weinberg Water Resources Consulting, LLC
Michael R. Welch, Ph.D., P.E.
July 2018
Sept. 27, 2022 Item #10 Page 14 of 279
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Sept. 27, 2022 Item #10 Page 15 of 279
EWA Water Reuse Feasibility Study
Executive Summary
July 2018 i
Table of Contents
Executive Summary ...................................................................................................................................... 1
ES-1 Introduction .............................................................................................................................. 1
ES-2 Background of Potable Reuse in California (TM 1) ................................................................ 1
ES-3 Stakeholder Involvement Plan (TM 6) ..................................................................................... 2
ES-4 Portfolio of Options (TM 2) ..................................................................................................... 3
ES-5 Preferred Project Identification (TM 3) ................................................................................... 7
ES-6 Project Phasing (TM 4) .......................................................................................................... 10
ES-7 Funding Opportunities (TM 5) ............................................................................................... 14
ES-8 Conclusions and Next Steps ................................................................................................... 15
List of Figures
Figure ES-1: Projected 2040 Monthly Flows and Potential for Potable Reuse ............................................ 3
Figure ES-2: Reuse Opportunities using EWPCF Effluent and Potential Flows .......................................... 4
Figure ES-3: Regional Context for Reuse Project and Potential Receptors of EWPCF Effluent ................. 5
Figure ES-4: Capital Cost Summary for Options F, G, and H ...................................................................... 7
Figure ES-5: Unit Cost Summary for Options F, G, and H .......................................................................... 8
Figure ES-6: Conceptual Pipeline Alignment for Option H ....................................................................... 10
Figure ES-7: Proposed AWTF Treatment Train for RWA ......................................................................... 10
Figure ES-8: EWRFS Project Treatment Facilities Footprint (16 mgd RWA) ........................................... 11
Figure ES-9: Sensitivity of Unit Costs with Increased Water for RWA and Outside Funding1 ................. 13
Figure ES-10: Comparative Cost of Water for Option H and Regionally Available Alternatives ............. 13
Figure ES-11: Implementation Schedule for EWA’s Potable Reuse Project (Phase 1) .............................. 14
List of Tables
Table ES-1: Portfolio of Options Summary .................................................................................................. 6
Table ES-2: Summary of Key Considerations for EWA’s Potable Reuse Options ...................................... 9
Table ES-3: Cost Summary for Option H at 16 mgd .................................................................................. 12
Table ES-4: Funding Program Ranking ...................................................................................................... 15
Attachments
Attachment 1 - TM1: Background of Potable Reuse in California
Attachment 2 - TM2: Portfolio of Options
Attachment 3 - TM3: Preferred Project Identification
Attachment 4 - TM4: Phasing of Preferred Project
Attachment 5 - TM5: Funding Opportunities
Attachment 6 - TM6: Stakeholder Involvement Plan
\\wc\shared\Projects\RMC\IRV\0305 - Encina Wastewater Authority\59 - Water Reuse FS\B. Project Work\8. Final Report\EWRFS_ExecSummary_Final.docx
Sept. 27, 2022 Item #10 Page 16 of 279
EWA Water Reuse Feasibility Study
Executive Summary
July 2018 ii
List of Abbreviations
AADF annual average daily flow
AF acre-feet
AFY acre-feet per year
AOP advanced oxidation process
AWT advanced water treatment
AWTF advanced water treatment facility
BAF biologically activated filtration
CEQA California Environmental Quality
Act
CDP Carlsbad Desalination Plant
DDW State Water Resources Control
Board Division of Drinking Water
DPR direct potable reuse
EWA Encina Wastewater Authority
EWPCF Encina Water Pollution Control
Facility
FAT full advanced treatment
gpd gallons per day
gpm gallons per minute
GWA Groundwater augmentation
HGL hydraulic grade line
HP horsepower
IPR indirect potable reuse
IRWM Integrated Regional Water
Management
LF Linear feet
LRP Local Resources Program
LWSIP Local Water Supply Incentive
Program
LWSD Local Water Supply Development
mgd million gallons per day
mg/L milligram per liter
MF microfiltration
MWD Metropolitan Water District
NDN nitrification/denitrification
NPDES National Pollutant Discharge
Elimination System
NPR non-potable reuse
NSDRC North San Diego Reuse Coalition
O3 ozone
O&M operations and maintenance
OMWD Olivenhain Municipal Water District
psi pounds per square inch
RRT response retention time
RO reverse osmosis
ROWD Report of Waste Discharge
RWA raw water augmentation
RWQCB Regional Water Quality Control
Board
SDCWA San Diego County Water Authority
SDWD San Dieguito Water District
SEJPA San Elijo Joint Powers Authority
SFID Santa Fe Irrigation District
SRF State Revolving Fund
SWA surface water augmentation
SWRCB State Water Resources Control
Board
TDWA treated drinking water augmentation
TM technical memorandum
UF ultrafiltration
UV ultraviolet irradiation
VWD Vallecitos Water District
WDR Waste Discharge Requirements
WIIN Water Infrastructure Improvements
for the Nation
WRF Water Reclamation Facility
WRFP Water Recycling Funding Program
WRR water recycling requirements
WTP water treatment plant
WWTP wastewater treatment plant
Sept. 27, 2022 Item #10 Page 17 of 279
EWA Water Reuse Feasibility Study
Executive Summary
July 2018 1
Executive Summary
ES-1 Introduction
As required by Encina Wastewater Authority’s (EWA) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) identifies a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd). Ultimately, the Study serves to advance EWA’s mission of resource recovery and
contributing to sustaining and enhancing the region’s water resources.
A series of technical and regulatory issues were analyzed, and alternative project concepts were developed
during the Study. The analysis is documented in a series of technical memoranda (TM):
• TM 1 – Background of Potable Reuse in California
• TM 2 – Portfolio of Options
• TM 3 – Preferred Project Identification
• TM 4 – Phasing of Preferred Project
• TM 5 – Funding Opportunities
• TM 6 – Stakeholder Involvement Plan
This Executive Summary provides an overview of the water reuse opportunities for EWA, identifies the
Preferred Project along with a recommended approach and schedule for implementation that will help EWA
chart a path forward. The complete TMs referenced above are attached to this Executive Summary, which
together constitute the Study’s final report.
ES-2 Background of Potable Reuse in California (TM 1)
Non-potable reuse (NPR) can be a vital component of a diverse water supply portfolio. In Southern
California, non-potable reuse systems often serve to offset imported water by providing recycled water for
irrigation demands. This is an important function, particularly in semi-arid San Diego County where
approximately 84 percent of the water supply is imported from hundreds of miles away via the State Water
Project and the Colorado River Aqueduct1. However, NPR does have limitations compared to potable water
reuse. These include the fact that non-potable water has limited applications due to its quality; the cost of
constructing, operating, and maintaining dedicated "purple pipe" infrastructure in parallel with potable
water infrastructure; and the limited ability to maximize use given the seasonal nature of irrigation demands.
Indirect Potable Reuse (IPR) is the incorporation of recycled water into the drinking water supply system
after storage in an environmental buffer, such as an aquifer or reservoir, and, in some cases, additional
treatment steps. The two primary types of IPR are Groundwater Augmentation (GWA) and Surface Water
Augmentation (SWA)2. There are currently several State regulations that govern IPR.
The State Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) has specific
regulations for Groundwater Replenishment Reuse Projects (GRRPs) included in Title 22. These were last
revised in July 2015. There are currently two types of regulated GRRPs: surface application and subsurface
application. For surface application, additional treatment can be provided through percolation and dilution
of the recycled water with groundwater in the groundwater basin. Subsurface application (injection) of
1 Source: SDCWA 2016, http://www.sdcwa.org/san-diego-county-water-sources, Accessed 11/8/16.
2 The terms “surface water augmentation” and “reservoir water augmentation” may be used interchangeably.
Sept. 27, 2022 Item #10 Page 18 of 279
EWA Water Reuse Feasibility Study
Executive Summary
July 2018 2
recycled water directly into the groundwater basin requires full advanced treatment that includes reverse
osmosis (RO) and an advanced oxidation process (AOP).
Regulations for SWA were adopted by SWRCB on March 6, 2018. The new regulations set requirements
for the quality of treated recycled water that can be added to a surface water reservoir that is used as a
source of drinking water. The regulations also specify the percentage of recycled water that can be added
and how long it must reside there before being treated again at a surface water treatment facility and
provided as drinking water.
DDW is also developing regulations for Direct Potable Reuse (DPR). DPR is differentiated from IPR based
on the absence of an environmental buffer. SWRCB defines DPR as the planned introduction of recycled
water either directly into a public water system (Treated Drinking Water Augmentation [TDWA]), or into
a raw water supply immediately upstream of a water treatment plant (Raw Water Augmentation [RWA]).
No uniform regulations have been established within the State of California or nationally for DPR.
However, AB 574 requires SWRCB to establish a framework for the regulation of DPR projects by June 1,
2018 and to adopt uniform water recycling criteria for RWA by 2023. SWRCB published a Draft Proposed
Framework for Regulating Direct Potable Reuse in California in April 2018. The two DPR facilities
globally that are currently operating (one in Windhoek, Namibia and the other in Big Spring, Texas) have
site-specific permits and treatment requirements set forth by regional regulatory agencies.
The following considerations can facilitate the determination of timing and feasibility of various reuse
options for EWA:
• There is significant experience with successful non-potable water reuse projects in North San Diego
County, which are expected to expand over the next 10 to 20 years and continue providing a well-
recognized valuable resource to the community.
• Final regulations allow for confident implementation of IPR projects, supported by decades of
successful groundwater recharge project operations in California.
• DPR has been determined to be feasible in California by DDW. Regulations related to RWA are
expected by 2023 after further research, expert consultation, and public engagement to ensure the
regulations protect public health while increasing drinking water supplies. No timeframe has been
established for development of regulations related to TDWA.
• Nationally, there are several established and very successful IPR projects. Some of these projects
have been in operation for over 40 years.
ES-3 Stakeholder Involvement Plan (TM 6)
A stakeholder involvement plan was developed early in the project to identify stakeholder activities to be
carried throughout the Study. The plan is presented in TM 6. At this stage, EWA has taken a leadership role
by developing this Water Reuse Feasibility Study; however, EWA’s role for future work will need to be
carefully defined. Although EWA would likely be the producer of recycled water, local water purveyors
and others will ultimately control the end beneficial use. Developing the roles and responsibilities of EWA
in a large-scale beneficial reuse project is critical to the formation of a business case and structure to
implement a project.
The initial outreach activity was directed at EWA Member Agencies through a letter from EWA’s General
Manager to each individual Member Agency. The North San Diego Water Reuse Coalition (NSDWRC)
was a convenient stakeholder group to approach next because it was already an established structure that
included most of the northern San Diego County retail water agencies. In addition, the City of San Diego
and San Diego County Water Authority (SDCWA) were included due to their ownership in some of the
facilities being considered in the Reuse Study Options.
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Several presentations were made to the various stakeholder groups throughout the Study to:
• Obtain feedback from the local water purveyors to develop the best alternatives possible,
• Build on work done by NSDWRC,
• Discuss options for cost responsibility assumptions, ownership of facilities, and permit
responsibilities, and
• Seek a consensus through group discussion on the initial screening criteria and the highest ranked
alternatives.
ES-4 Portfolio of Options (TM 2)
An update of the future flow projections to the EWPCF was performed as part of the EWPCF Process
Master Plan (EWA 2016). This update was deemed necessary because of the significant drop in wastewater
flows during the 2011-2016 drought. This analysis resulted in a range of estimated flows by 2040 between
26 mgd and 31 mgd, revised down from previous projections of 40.5 mgd.
Any new reuse project being considered by EWA must be compatible with other current and planned reuse
efforts being undertaken by the EWA Member Agencies. Based on a survey of these agencies, demand of
EWPCF effluent for NPR is projected to be as high as 12.5 mgd by 2040, as shown in Figure ES-1. This
projection includes 10 mgd to supply the City of Carlsbad’s Water Reclamation Facility (WRF) and 2.5
mgd to supply Leucadia Wastewater District’s Gafner WRF. Assuming reverse osmosis (RO) would be
part of the treatment train for all potable reuse projects, approximately 20 mgd is estimated to be available
for year-round potable reuse after accounting for projected NPR and RO concentrate losses.
Figure ES-1: Projected 2040 Monthly Flows and Potential for Potable Reuse
TM 2 presents a wide range of opportunities for potable reuse projects within the North San Diego County
region. Each potential receptor of EWPCF effluent was categorized by form of reuse—including NPR,
GWA, SWA, RWA, and TDWA (Figure ES-2). The initial estimates of potential potable reuse flows
account for reserving a baseline of 12.5 mgd for NPR by EWA Member Agencies. The existing regional
water and wastewater facilities that may be involved in options for reuse are shown in Figure ES-3.
0
5
10
15
20
25
30
35
Flow (mgd, average)Available for
Potable Reuse
EWPCF Effluent
Effluent Available
Year-Round
Projected NPR
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Figure ES-2: Reuse Opportunities using EWPCF Effluent and Potential Flows
Note: Flows denoted with an asterisk (*) require further evaluation (beyond the scope of this Study) to confirm reuse flows.
Based on the various potable reuse opportunities described in TM 2, nine options were identified as EWA’s
Portfolio of Options for this Reuse Study, summarized in Table ES-1, by combining opportunities
considering peak demand requirements. A qualitative set of criteria was developed to allow for an initial
screening of the nine options in EWA’s Portfolio of Options prior to embarking on a more detailed
quantitative evaluation to include capital and operating costs. For each criterion, a weighting factor was
assigned and scoring levels were selected based on the expected range and relative impact on project
feasibility. The nine options were then screened based on the criteria identified. The five criteria consisted
of the following:
• Anticipated regulatory and permitting effort;
• Treatment and engineered storage requirements;
• Operational considerations;
• Conveyance infrastructure needed; and,
• Stakeholder input and potential institutional challenges.
Based on the results from the screening evaluation, the following were identified as the three most favorable
options that were carried forward for further analysis to determine the preferred project:
1. Option F: San Dieguito Reservoir (SWA) and CDP Product Water (TDWA) (Ranked 3rd)
2. Option G: San Dieguito Reservoir (SWA) and Second Aqueduct (RWA) (Ranked 1st)
3. Option H: Second Aqueduct (RWA) and San Marcos Basin (GWA) (Ranked 2nd)
Non-Potable
Reuse(NPR)
Carlsbad WRF
10 mgd
Gafner WRF
2.5 mgd
Meadowlark WRF
6.5 mgd
Groundwater
Augmentation(IPR)
San Dieguito Basin & San Elijo Basin
Up to 2 mgd*
San Marcos
Basin
Up to 2 mgd*
Surface Water
Augmentation (IPR)
Olivenhain & Hodges Reservoirs
15.7 mgd
San Dieguito
Reservoir
3.1 mgd
Raw Water
Augmentation (DPR)
Twin Oaks WTP
15.7 mgd
Carlsbad Desalination Plant
15.7 mgd
Second Aqueduct (Raw Water)
15.7 mgd
Treated Drinking
Water Augmentation (DPR)
SDCWA
Carlsbad Desalination Plant(Finished Water)
11.1 mgd
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Figure ES-3: Regional Context for Reuse Project and Potential Receptors of EWPCF Effluent
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Table ES-1: Portfolio of Options Summary
NPR
Recycled
Water
Ground-
water
Large
Res.
Small
Res.
Source
Water
Treated
Water SE Brine
A Carlsbad Desalination Plant (CDP) Influent 12.5 - - - 11.1 - 0 7.4 11.1 23.6
B CDP Product Water 12.5 - - - - 15.7 0 2.8 15.7 28.2
C Olivenhain Reservoir 12.5 - 15.7 - - - 0 2.8 15.7 28.2
D San Dieguito Reservoir + Olivenhain Reservoir 12.5 2.0 10.6 3.1 - - 0 2.8 15.7 28.2
E San Dieguito Reservoir + CDP Influent 12.5 2.0 - 3.1 7.5 - 0 5.9 12.6 25.1
F San Dieguito Reservoir + CDP Product Water 12.5 2.0 - 3.1 - 10.6 0 2.8 15.7 28.2
G San Dieguito Reservoir + 2nd Aqueduct (Raw)12.5 2.0 - 3.1 10.6 - 0 2.8 15.7 28.2
H Second Aqueduct (Raw) + San Marcos Basin 12.5 2.0 - - 13.7 - 0 2.8 15.7 28.2
I Twin Oaks WTP Influent + San Marcos Basin 12.5 2.0 - - 13.7 - 0 2.8 15.7 28.2
Option Description DPR
Total
Potable
Reuse
(mgd)
Option
ID
Total
Reuse
(mgd)
IPR
Projected 2040 Peak Production (mgd)
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ES-5 Preferred Project Identification (TM 3)
In TM3, the three highest ranked project options are evaluated based on unit cost and non-cost factors
including potential implications to EWPCF operations, advanced treatment requirements, anticipated
timeframe for regulatory acceptance, project implementation timeline, and expected stakeholder support.
The capital costs for the three options are summarized under three main categories and are shown on Figure
ES-4:
• EWPCF Treatment Improvements: consisting primarily of primary effluent flow equalization,
aeration basin retrofits for nitrification-denitrification, increased secondary clarifier capacity, and
addition of tertiary filtration.
• Advanced Water Treatment Facility (AWTF): development of a new treatment facility on
EWA’s South Parcel to provide a level of treatment based on current and/or expected regulations
that is protective of human health and can be achieved with available technologies.
o Option G for SWA would require an AWTF providing full advanced treatment (FAT)
consisting of membrane filtration (MF/UF), reverse osmosis (RO), and an ultraviolet
light/advanced oxidation step (UV/ AOP).
o In addition to an AWTF providing FAT, Option H and Option G for RWA would also
require ozonation (O₃) with BAF as pretreatment before UF to provide further pathogen
removal and enhanced water quality.
o In addition to an AWTF providing FAT with O3/BAF, Option F for TDWA would require
further treatment by a tailored Water Treatment Plant (WTP) consisting of an Engineered
Storage Buffer (ESB) with chlorination (Cl2) and a high-flux UF system. This treatment
train is anticipated to be required for integration with the potable water system.
• Conveyance Concepts: based on a preliminary hydraulic evaluation, the approximate conveyance
pipe sizes, pressure requirements, pumping requirements, and alignment options were determined
to convey the advanced treated water from the proposed AWTF to the receptor(s) associated with
each option.
Figure ES-4: Capital Cost Summary for Options F, G, and H
$89 $89 $89
$284 $234 $234
$143 $287
$180
$516
$611
$504
$-
$100
$200
$300
$400
$500
$600
$700
Option F
Carlsbad Desal.
TDWA
Option G
San Dieguito SWA
+ RWA
Option H
RWA + San Marcos
GWACapital Cost (millions)Conveyance
AWTF
EWPCF
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The annual O&M costs are summarized for the three options under the following categories:
• Power for treatment (including both the incremental power requirements at the EWPCF and the
requirements for the AWTF)
• Power for conveyance (pumping)
• Other O&M costs: this includes equipment rehabilitation/replacement, consumables (across all
improved and new facilities), and labor for the AWTF and the conveyance system (pipeline and
pump station maintenance)
Unit costs for water produced were developed for each option, including O&M costs plus annualized capital
costs, to assist with identification of the preferred project option (see Figure ES-5).
Figure ES-5: Unit Cost Summary for Options F, G, and H
Note: Annualized capital costs assume 100% financing at a 2.0% annual interest rate over a 30-year term.
In evaluating the relative merits of the three options, the following criteria were considered in selecting the
preferred option (as summarized in Table ES-2):
• Unit Cost of water
• Likely timeframe for regulatory acceptance and project implementation
• Complexity of operations and compliance
• Anticipated stakeholder support
$1,310 $1,540 $1,270
$428
$438
$386
$320
$304
$304
$896
$871
$752
$2,960
$3,160
$2,720
$-
$500
$1,000
$1,500
$2,000
$2,500
$3,000
$3,500
Option F
Carlsbad Desal. TWA
Option G
San Dieguito SWA + RWA
Option H
RWA + San Marcos GWACost of Water ($/af)Power
(Conveyance)
Power
(Treatment)
Other O&M
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Table ES-2: Summary of Key Considerations for EWA’s Potable Reuse Options
Option F: Carlsbad
Desal, TDWA
Option G: San Dieguito
SWA + RWA
Option H: RWA + San
Marcos GWA
Cost of Water
(at 20.5 mgd
influent)
$2,960/af $3,160/af $2,720/af
Time to
Implement 15-20+ years 10-15 years 10+ years
Regulatory
Considerations Timeframe uncertain Expected by 2023 Expected by 2023
Complexity of
Operations &
Compliance
AWTF + ESB +
Blending & Pumping at
CDP
AWTF +
Up to three forms of
potable reuse (reservoir +
groundwater + raw water)
AWTF +
Up to two forms of potable
reuse (raw water +
groundwater)
Key
Stakeholders
SDCWA,
Poseidon
SEJPA, SDWD, SFID,
OMWD, SDCWA
Vallecitos,
SDCWA
Based on the considerations identified in Table ES-2, Option H was selected as the Preferred Project for
further refinement under this Study. Relative advantages include lower cost of water than Options F and G,
an earlier timeframe for implementation considering the regulatory requirements and coordination required
with other key stakeholders, and simpler operations. EWPCF tertiary effluent would undergo advanced
water treatment to produce water suitable for RWA. The facilities required for the RWA portion of the
Preferred Project would include:
• Upgrades to the EWPCF, including primary effluent flow equalization, conversion of the secondary
process to nitrification-denitrification and tertiary filters for the flow directed to the AWTF.
• AWTF (FAT with O3 + BAF) that produces up to 16 mgd of advanced treated recycled water
• Pump station and conveyance pipeline to the SDCWA Second Aqueduct, Pipeline No. 5.
If, under Option H, Vallecitos Water District (VWD) pursues GWA in the San Marcos groundwater basin
(within its service area), additional facilities required include two groundwater injection wells, conveyance
pipeline to the injection wells, and two groundwater extraction wells with wellhead treatment (note that
costs for these facilities are included in Figure ES-5 above). Because the GWA project facilities would be
downstream of the connection point to the SDCWA Aqueduct (see conceptual alignment in Figure ES-6
below), the water for GWA would be treated to the same standards as for RWA.
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Figure ES-6: Conceptual Pipeline Alignment for Option H
ES-6 Project Phasing (TM 4)
TM 4 presents the approach to phasing the implementation of the Preferred Project. This TM provides the
initial recommendations for the secondary improvements and advanced treatment facilities, evaluation of
AWTF size and future expansion capability, and a framework implementation plan and schedule.
The recommended phased approach consists of improvements to the EWPCF and construction of a new 16
mgd AWTF for potable reuse, using the treatment train shown in Figure ES-7. This would require a total
area of approximately 286,100 ft2 (6.6 acres) for the AWTF alone, in addition to the other facilities shown
on Figure ES-8. A future expansion phase could increase the production to 25 mgd depending on flows
available, with the AWTF footprint increasing to approximately 8.9 acres. Therefore, it is recommended to
reserve adequate space on EWA’s South Parcel to accommodate the expanded footprint within the 22.9
acres currently available.
Figure ES-7: Proposed AWTF Treatment Train for RWA
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Figure ES-8: EWRFS Project Treatment Facilities Footprint (16 mgd RWA) Sept. 27, 2022Item #10 Page 28 of 279
EWA Water Reuse Feasibility Study
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July 2018 12
Excluding the GWA aspect, the initial phase of the Preferred Project at 16 mgd product water (20.5 mgd
influent, minus brine losses) has a capital cost of $481m and annual operations and maintenance cost of
$22m. The Preferred Project’s annualized cost over 30 years equates to $2,450/AF, as summarized in Table
ES-3.
Table ES-3: Cost Summary for Option H at 16 mgd
Option H: RWA to Second Aqueduct (16 mgd) Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Treatment (FAT + O3/BAF) $234,400,000 at 20.5 mgd influent rate
Conveyance - East $157,000,000 at 20.5 mgd influent rate
Total Capital Cost $480,400,000
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $5,403,000 24/7/365 operations
Power - Conveyance $9,864,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $5,537,000 All new facilities (incl. EWCPF)
Labor $1,134,000 AWTF + Conveyance
Total Annual O&M Cost $21,938,000
Cost of Water
Annualized Capital Cost $21,450,000 2.0% rate, 30-yr term
Total Annual Cost $43,388,000 for first 30 years
Annual Yield 17,800 acre-feet
Unit Cost of Water $2,450 per acre-foot
Unit Cost of Water Sensitivity Analysis
The unit cost of water for Option H were initially developed based on reserving 12.5 mgd year-round for
NPR by EWA Member Agencies, assumes there is no outside funding and it includes the VWD GWA
project facilities. A sensitivity analysis (Figure ES-9) of the unit costs, excluding the GWA project facilities
(i.e., RWA project only), was developed considering the following:
• Amount of water reserved for NPR water reduced to 8.0 mgd (more likely), resulting in an increased
RWA project yield of 20 mgd (vs. 16 mgd baseline)
• Inclusion or exclusion of potential funding opportunities, including 20 percent outside funding and
production incentives (local rebates) that would reimburse the participating agencies $500 per acre-
foot for the first 25 years of operation.
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Figure ES-9: Sensitivity of Unit Costs with Increased Water for RWA and Outside Funding1
Note: Costs shown are based on Option H excluding GWA by VWD.
The anticipated cost of untreated (raw) water purchased from the SDCWA between 2025 and 2045 is shown
in comparison with the projected range of costs for Option H on Figure ES-10. The range of costs for Option
H as shown are with capital costs inflated at 2.5 percent per year and O&M cost escalated at 1.5 percent
annually. As can be seen from Figure ES-10, the projected cost of water derived from Option H would
match the cost of untreated SDCWA water by 2040 or earlier depending on flow available and level of
outside funding.
Figure ES-10: Comparative Cost of Water for Option H and Regionally Available Alternatives
$1,210
$547
$1,140
$451
$375
$375
$368
$368
$304
$304
$279
$279
$554
$554
$552
$552
$2,450
$1,780
$2,340
$1,660
$-
$500
$1,000
$1,500
$2,000
$2,500
$3,000
Option H
16 mgd RWA
Option H
16 mgd RWA
+ Funding
Option H
20 mgd RWA
Option H
20 mgd RWA
+ FundingCost of Water ($/af)Power
(Conveyance)
Power
(Treatment)
Other O&M
Annualized
Capital
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Implementation Schedule
Additional planning, pilot studies, environmental review, public outreach and regulatory coordination are
needed to refine the selected Preferred Project concept and verify economics. In addition, regulations
related to RWA are not expected until at least 2023 after further research is completed. By laying out an
implementation schedule for the initial phase of the Preferred Project, it was estimated that steady progress
toward implementation would require approximately 10 years until the start of project operations (Figure
ES-11).
Figure ES-11: Implementation Schedule for EWA’s Potable Reuse Project (Phase 1)
ES-7 Funding Opportunities (TM 5)
TM 5 identifies local, state, and federal funding opportunities for the Project, including funding program
objectives, eligibility criteria, cost share requirements, and activities that could be funded based on funding
programs that existing today. It is likely that in the future additional funding programs may be available.
Five of the funding programs described in TM 5 were determined to be the most applicable to EWA’s water
reuse project and were ranked as shown in Table ES-4.
Planning
EWPCF Improvements
AWTF
Pilot Testing
Pipeline Alignment
Funding
Funding Plan
State
Federal
Regulatory
Strategy
Engineering Report
Permitting
Environmental
CEQA
Design/Construction
EWPCF Improvements
AWTF
Conveyance
Stakeholder/Public Outreach
Stakeholder Outreach
Public Outreach
Start of Project Operations
TASKS 9 1056784123
YEARS
●
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Table ES-4: Funding Program Ranking
Rank Program Explanation
1
SWRCB Water
Recycling Funding
Program (WRFP)
WRFP planning grant funds are currently available and could support
development of a Feasibility Study with up to $75,000 at a 50% match.
2
San Diego Integrated
Regional Water
Management (IRWM)
Program
IRWM funding is a strong option because the competition occurs at the
regional scale, where local water agency partners can be an advocate
for the EWA Project. Planning activities can be paired with other
“shovel-ready” capital projects to secure grant funding (using the
capital project costs as match) or phased to allow for work to proceed
in stages.
3
USBR Water
Infrastructure
Improvements for the
Nation (WIIN)
Program
WIIN funding could be used to fund planning, design, and/or
construction of all potential project components. Construction activities
can be phased to pursue construction of different components of the
Project in each 2-year funding cycle until the $20 million grant is
achieved.
4
SWRCB Clean Water
State Revolving Fund
(SRF) Loan Program
EWA and partnering agencies would likely qualify for low-interest
financing through the Clean Water SRF Program, which would cover
construction activities up to the full project cost. Extensive application
materials are necessary, including completion of CEQA and all
permits.
5
MWD Local
Resources Program
(LRP) / SDCWA Local
Water Supply
Incentive Program
(WSIP)
The LRP and LWSIP are likely to become available to SDCWA
member agencies again; however, the timeline or availability of funds
is uncertain. Further, these funds only apply to the cost of delivered
water, so they may only be awarded after all construction and start-up
activities are complete.
Several water supply agencies within the region have capitalized on multiple grant and loan programs. In
the near-term, pursuit of the SWRCB’s Water Recycling Funding Program and the San Diego Integrated
Regional Water Management Program grants could provide funding for further planning activities. In the
long-term, the Federal Water Infrastructure Improvements for the Nation, State Revolving Fund Program,
and MWD’s Local Resource Program / SDCWA’s Local Water Supply Development funding should be
pursued if available. To increase the chances of receiving funding for any future phases of EWA’s water
reuse project, it is recommended that EWA and any partnering agencies pursue all funding options
available.
ES-8 Conclusions and Next Steps
EWA’s wastewater flows and facilities represent a unique opportunity and a centralized location for large-
scale production of recycled water that could capture economies of scale to the benefit of the region. EWA’s
experience in water treatment and water quality may well make it suitable to take on the responsibility for
the AWTF required for potable reuse. The presence and available capacity of a deep ocean outfall is
conducive to siting the AWTF near the EWPCF for disposal of reject streams.
Demand for non-potable reuse in the region is not projected to be sufficient to fully utilize the available
effluent at the EWCPF, especially considering the seasonal nature of irrigation demands. Therefore, potable
reuse would be necessary to minimize discharges of EWPCF effluent to the Pacific Ocean. Although the
cost of water estimated for EWA’s RWA option is higher than current SDCWA untreated water rates (like
other recycled water projects being implemented in the region), SDCWA’s costs are projected to rise over
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July 2018 16
time and EWA’s RWA project may become cost-competitive by the time it could begin delivering water in
the mid to late 2020s.
Because the production of a new water supply by EWA is not required to comply with its NPDES permit
or any other state or federal requirement, the cost of the RWA option beyond wastewater treatment and
disposal would be the responsibility of water purveyors. As such, future planning and implementation
activities should be pursued on a cost share basis with participating local and regional water suppliers.
However, it should be noted that the draft Amendment to the Recycled Water Policy released by the
SWRCB on May 9, 2018 identified the following:
• Goal: Increase the use of recycled water from 714,000 afy in 2015 to 1.5 million afy by 2020 and
to 2.5 million by 2030.
• Goal: Minimize the direct discharge of treated municipal wastewater to […] ocean waters, except
where necessary to maintain beneficial uses. Under this goal, treated municipal wastewater does
not include brine discharges from recycled water facilities or desalination facilities.
• The State Water Board will evaluate progress toward these goals and revise the goals or establish
mandates as necessary.
As reflected by the RWA project Implementation Schedule (Figure ES-11), the activities identified during
the initial phases of the project are focused on:
• Identifying the potential impacts on the EWPCF.
• Refining the design criteria for the AWTF and pilot testing.
• Strategizing the approach to defining the regulatory requirements for RWA.
• Developing a funding plan to maximize the opportunities for outside funding.
• Determining a likely corridor for the conveyance pipeline to the SDCWA raw water pipeline.
If EWA’s Board of Directors authorizes staff to continue planning and permitting activities beyond this
Study, future stakeholder outreach should focus on developing a formal partnership with the water
purveyor(s) that would use the purified raw water produced from EWPCF effluent. The cost of the initial
activities identified in the implementation schedule could be shared by local and regional water purveyors
interested in continuing to refine the costs and partnering on the project.
Defining EWA’s role after the Feasibility Study will be key to any implementation plan of wider reuse of
EWA’s valuable water resources. EWA should invite continued discussions with its potential partners
(retail water agencies), and the next steps could also involve significant policy and financial deliberations
by its Board and Member Agencies.
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Attachment 1 - TM1: Background of Potable Reuse in
California
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July 2018 1
Technical Memorandum No. 1
EWA Water Reuse Feasibility Study
Subject: Background of Potable Reuse in California
Prepared for: Encina Wastewater Authority
Prepared by: Andrea F. Corral, Ph.D., Andrew Salveson, P.E. | Carollo Engineers
Nathan Chase, P.E. | Woodard & Curran
Bryan Trussell, P.E. | Trussell Technologies, Inc.
Reviewed by: Eva Steinle-Darling, Ph.D., P.E. | Carollo Engineers
Scott Goldman, P.E. | Woodard & Curran
Shane Trussell, Ph.D., P.E. | Trussell Technologies, Inc.
Date: July 2018 (Draft issued: November 2016)
Table of Contents
1 Introduction ........................................................................................................................................... 3
1.1 Feasibility Study Background ....................................................................................................... 3
1.2 Objectives ..................................................................................................................................... 3
2 Water Reuse Regulatory Setting ........................................................................................................... 4
2.1 Non-Potable Reuse ........................................................................................................................ 4
2.2 Indirect Potable Reuse .................................................................................................................. 5
2.3 Direct Potable Reuse ..................................................................................................................... 8
3 Non-Potable Water Reuse in North San Diego County ...................................................................... 14
3.1 Carlsbad Water Reclamation Facility ......................................................................................... 14
3.2 Leucadia Wastewater District Gafner Water Reclamation Facility ............................................ 14
3.3 Vallecitos Water District Meadowlark Water Reclamation Facility .......................................... 14
3.4 San Elijo Water Reclamation Facility ......................................................................................... 15
4 Potable Water Reuse Case Studies ...................................................................................................... 16
4.1 Existing Indirect Potable Water Reuse in California .................................................................. 18
4.2 Planned Direct Potable Water Reuse Projects in California ....................................................... 20
4.3 Existing Potable Reuse Projects Outside of California ............................................................... 22
5 Conclusions ......................................................................................................................................... 25
6 References ........................................................................................................................................... 25
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TM1: Background of Potable Reuse in California
July 2018 2
List of Figures
Figure 2-1: SWA Project Schematic Process Flow Diagram ........................................................................ 6
Figure 2-2: Small Reservoir DPR ............................................................................................................... 11
Figure 2-3: RWA ........................................................................................................................................ 11
Figure 2-4: TDWA (“Flange-to-Flange” DPR) .......................................................................................... 11
Figure 2-5: DPR Treatment Train Example without RO ............................................................................ 12
Figure 4-1: Existing and Planned Potable Reuse Projects in California ..................................................... 17
Figure 4-2: GWRS RO Membranes ............................................................................................................ 18
Figure 4-3: Rio Hondo Spreading Grounds, located off-channel ............................................................... 18
Figure 4-4: City of Los Angeles Terminal Island AWPF RO Train ........................................................... 19
Figure 4-5: San Diego Pure Water Demonstration Facility ........................................................................ 20
Figure 4-6: City of Ventura DPR Demonstration Facility .......................................................................... 21
Figure 4-7: Lake Lanier, Georgia ............................................................................................................... 22
Figure 4-8: Colorado River Municipal Water District’s Raw Water Production Facility .......................... 23
Figure 4-9: CEC Comparison between DPR Product Water and Existing Source (Moss Creek Lake) ..... 23
Figure 4-10: Potable Reuse Safety Demonstration Using Understandable Methods (Beer) ...................... 24
List of Tables
Table 2-1: California Recycled Water Classifications .................................................................................. 4
Table 2-2: Criteria for Potable Reuse via Groundwater Augmentation ........................................................ 5
Table 2-3: SWA Pathogenic Microorganism Control ................................................................................... 7
Table 3-1: Recycled Water Projections ...................................................................................................... 14
Table 4-1: Operational Potable Reuse Projects in California (as of 2016) ................................................. 16
\\wc\shared\Projects\RMC\IRV\0305 - Encina Wastewater Authority\59 - Water Reuse FS\B. Project Work\1. Background\EWRFS TM1_Background.docx
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1 Introduction
1.1 Feasibility Study Background
As required by the Encina Wastewater Authority (EWA) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) identifies a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd).
Within the context of potable reuse in California, the Study’s focus was on developing of a broad portfolio
of options for reuse projects using EWPCF effluent; screening the portfolio down to a short list for
feasibility evaluation and conceptual cost analysis; identifying a preferred reuse project and phasing
approach for implementation; determining applicability and timing of potential funding opportunities;
preparing a stakeholder involvement plan; and coordinating with EWA’s Member Agencies and other
stakeholders to engage with the Study development and recommendations. Ultimately, the Study is intended
to serve to advance EWA’s mission of resource recovery and contribute to sustaining and enhancing the
region’s water environment.
1.2 Objectives
The purpose of this Technical Memorandum (TM) is to present a brief background on non-potable water
reuse and potable water reuse in California, review select potable water reuse projects nationally, and
provide regional context for the portfolio of water reuse options to be developed in this Study. The TM is
organized as summarized below:
• Water Reuse Regulatory Setting: For each form of water reuse, this section provides a summary
of the regulatory status in California.
• Non-Potable Water Reuse in North San Diego County: this section presents a summary of
recycled water facilities operating in the region and their plans for expansion, with particular focus
on the facilities that currently utilize EWPCF effluent.
• Potable Water Reuse Case Studies: a summary of indirect potable reuse (IPR) and direct potable
reuse (DPR) projects in California and elsewhere that are in operation or advanced planning
stages—where possible, focusing on projects in the region that may be most relevant to EWA.
• Conclusions: the final section presents conclusions regarding the feasibility of the various forms
of water reuse, along with a discussion of challenges and lessons learned from other successful
water reuse projects that can be applied to EWA’s Study.
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2 Water Reuse Regulatory Setting
2.1 Non-Potable Reuse
Non-potable reuse (NPR) can be a vital component of a diverse water supply portfolio. In Southern
California, non-potable reuse systems often serve to offset imported water by providing recycled water for
irrigation demands. This is an important function, particularly in semi-arid San Diego County where
approximately 84 percent of the water supply is imported from hundreds of miles away via the State Water
Project and the Colorado River Aqueduct1. However, NPR does have limitations compared to potable water
reuse. These include the fact that non-potable water has limited applications due to its quality; the cost of
constructing, operating, and maintaining dedicated "purple pipe" infrastructure in parallel with potable
water infrastructure; and the limited ability to maximize use given the seasonal nature of irrigation demands.
In California, Title 22 Code of Regulations related to recycled water establishes the treatment requirements
for recycled water and the approved uses based on the level of treatment. Title 22 defines four classifications
of recycled water, which are determined by the level of treatment process, virus removal achieved, total
coliform (TC) bacteria, and turbidity levels. The four classifications of non-potable recycled water that are
currently permitted by the State Water Resources Control Board (SWRCB) Division of Drinking Water
(DDW) under Title 22 §60304 are summarized in Table 1 (SWRCB DDW, 2015).
Table 2-1: California Recycled Water Classifications
Treatment Level Approved Uses
Total Coliform
(TC) Standard
(median)
Disinfected Tertiary
Recycled Water
Spray Irrigation of Food Crops
Landscape Irrigation(1)
Non-restricted Recreational Impoundment
2.2 MPN/100 mL(4)
Disinfected Secondary-2.2
Recycled Water
Surface Irrigation of Food Crops
Restricted Recreational Impoundment 2.2 MPN/100 mL
Disinfected Secondary-23
Recycled Water
Pasture for Milking Animals
Landscape Irrigation(2)
Landscape Impoundment
23 MPN/100 mL
Undisinfected Secondary
Recycled Water
Surface Irrigation of Orchards and Vineyards(3)
Fodder and Fiber Crops and Pasture for non-
Milking Animals
N/A
Footnotes:
(1) Includes unrestricted access golf courses, parks, playgrounds, school yards, and other landscaped areas with similar access.
(2) Includes restricted access golf courses, cemeteries, freeway landscapes, and landscapes with similar public access restrictions.
(3) No fruit is harvested that has come in contact with irrigation water or the ground.
(4) In addition to the TC requirements, disinfected tertiary recycled water must also meet the following criteria:
a. Filtered such that this water does not exceed: an average of 2 NTU within a 24-hour period; 5 NTU more than 5
percent of the time within a 24-hour period; and 10 NTU at any time (Title 22 §60301.320).
b. Disinfected by one of the two following methods:
• Chlorine disinfection with a minimum product of chlorine residual (C) and contact time (t), or Ct, of 450
mg-min/L with a modal contact time of at least 90 minutes, or
• An alternative disinfection process, that, when combined with the filtration process, has been demonstrated
to inactivate and/or remove 5-log virus (Title 22 §60301.230).
1 Source: SDCWA 2016, http://www.sdcwa.org/san-diego-county-water-sources, Accessed 11/8/16.
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2.2 Indirect Potable Reuse
Indirect Potable Reuse (IPR) is the incorporation of tertiary or advanced treated recycled water into the
water supply system after storage in an environmental buffer such as an aquifer or a reservoir. There are
currently several State regulations that govern the use of IPR, as described in the following sections.
2.2.1 Groundwater Augmentation
DDW has promulgated regulations for Groundwater Replenishment Reuse Projects (GRRPs) in Title 22,
which were last revised in July 2015. There are currently two types of regulated GRRPs: surface and
subsurface application. General requirements for groundwater augmentation (GWA) are listed in Table 2.
Table 2-2: Criteria for Potable Reuse via Groundwater Augmentation
Selected Parameters Criteria
Pathogenic Microorganisms
Enteric virus 12-log reduction
Giardia cyst 10-log reduction
Cryptosporidium oocyst 10-log reduction
Chemicals
Total Organic Carbon (TOC) Maximum 0.25 mg/L in 95% of samples within first 20 weeks
Maximum 0.5 mg/L in 20-week running average
1,4-Dioxane 0.5-log reduction in the advanced oxidation process (2)
Total Nitrogen (TN) 10 mg/L maximum
Notes:
(1) Log reductions are from the point of raw wastewater to the point of finished water for drinking.
(2) Requirement for 1,4-dioxane removal applies to subsurface application (i.e., injection) projects only.
Surface Application (Spreading)
For surface application, additional treatment is provided through percolation and dilution of the recycled
water with groundwater in the groundwater basin. Surface spreading projects can use tertiary recycled water
if treatment through the soil (“soil aquifer treatment”) is shown to be sufficient. Regulations establish that
surface application projects can use up to 20 percent of recycled water initially and 80 percent of other
acceptable dilution water, as long as the specific recycled water contribution of TOC in the blended water
is below the values listed in Table 2. Per the regulations, "acceptable dilution water" is a water that meets
drinking water standards. If only tertiary water is used, the recharge water should remain in the groundwater
basin for a minimum of six months to meet the retention time target based on tracer tests or conservative
hydraulic modeling.
Subsurface Application (Injection)
Subsurface application (injection) of recycled water directly into the groundwater basin requires full
advanced treatment that includes reverse osmosis (RO) and an advanced oxidation process (AOP). Under
these conditions, no dilution water is required. Additionally, a minimum of two months of subsurface travel
time is required before extraction for potable use. These two months provides "Response Retention Time"
(RRT), which provides time to monitor water quality and respond to water quality concerns.
Direct injection projects have less room for innovation on the treatment train due to the close connectivity
between the injected water and the extraction wells. Cost savings have been realized by using alternative
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AOP systems, including the City of Los Angeles' new (12 mgd) ultraviolet light (UV) AOP that uses sodium
hypochlorite (NaOCl) instead of hydrogen peroxide (H2O2) as the oxidant.
2.2.2 Surface Water Augmentation
State Bill 918 required DDW to develop and promulgate regulations for surface water augmentation
(SWA), which were adopted on March 6, 2018. SWA projects are similar to GRRPs in that they also use
an environmental buffer in between treatment and distribution; however, for SWA, the buffer is provided
by a reservoir ahead of an existing surface water treatment plant. The following discussion is based on early
drafts of the regulations (released in 2015) made available as a result of the dialogue between the Expert
Panel and DDW. Key elements of the SWA regulations include pathogen and chemical control at the
advanced water treatment facility (AWTF) and retention time and dilution requirements in the reservoir.
Figure 2-1: SWA Project Schematic Process Flow Diagram
The following are key requirements for SWA:
1. Advanced Treatment - The SWA regulations require full advanced treatment of the recycled water
prior to delivery to the surface water reservoir. An advanced treatment train for SWA must include
reverse osmosis (RO) and oxidation that achieves at least 0.5-log reduction of 1,4-dioxane.
2. Dilution Requirement - The SWA regulations stipulate dilution requirements for recycled water
discharged into the reservoir. The basis of these requirements is that any 24-hour input of recycled
water to the reservoir must be mixed such that water withdrawn for use as drinking water will never
contain more than 1% of this input (or 10% with an additional log of pathogen treatment). The
intent of this requirement is to provide a buffer against off-specification water that enters the
reservoir; pathogen concentrations will be reduced by 2 logs, either through 100:1 dilution or 10:1
dilution with 1-log treatment (see pathogenic microorganism control requirements discussion
below for log removal requirements).
To demonstrate compliance with this requirement, the regulations require hydrodynamic modeling
that verifies the ability of the reservoir to meet this requirement under all conditions, as well as
completion of a tracer study with added tracer prior to the end of the first six months of operation.
The achievable dilution of a 24-hour input can be estimated using a simplifying assumption of
complete mixing in the reservoir. Under this assumption, dilution is related to the theoretical
retention time (τ) and the duration of the input (Δt):
dilution factor = τ / ∆t
3. Retention Time - The SWA regulations continue to incorporate the concept of retention time,
albeit taking into account the differences in hydrodynamics between an aquifer and a reservoir. The
regulations currently available stipulate that a reservoir used for SWA must have a minimum
theoretical retention time (τ) of 180 days, to be measured on a monthly basis as follows:
τ = 𝑉𝑡𝑜𝑡𝑎𝑙
𝑄𝑜𝑡𝑡
≥180 𝑑𝑎𝑦𝑠
where Vtotal is the volume in the reservoir at the end of the month and Qout is the total outflow from
the reservoir during that month. The regulations include a permitting pathway for projects where
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the V/Q is at least 60 days (i.e., within the “gap” between SWA and DPR—which is expected to
include projects with V/Q of less than 60 days).
4. Pathogenic Microorganism Control - The treatment requirements in the SWA regulations look
very similar to those for a GRRP, particularly with regard to pathogenic microorganism control. If
at least a 100:1 dilution is achieved in the reservoir, then the log removals for enteric virus,
Cryptosporidium, and Giardia are the same as in the GRRP regulations. If less than 100:1 but at
least 10:1 is dilution achieved in the reservoir, then an additional 1-log of pathogen treatment is
required by an additional process. If there is less than 10:1 dilution available in the reservoir, then
the project will likely be considered immediately upstream of a drinking water treatment plant and
will be defined as DPR (see Section 0 below for more details). Table 3 illustrates the required
removal criteria for enteric virus, Cryptosporidium, and Giardia.
Table 2-3: SWA Pathogenic Microorganism Control
Dilution
Enteric Virus
Removal
Cryptosporidium
Removal Giardia Removal
Dilution ≥ 100:1 12-log 10-log 10-log
100:1 ≥ Dilution ≥ 10:1 13-log 11-log 11-log
Dilution < 10:1 Not classified as surface water augmentation
GRRPs have the benefit of receiving log removal credit from the retention time underground,
whereas SWA projects do not. Instead, SWA projects allow treatment credits from the conventional
drinking water treatment plant downstream of the reservoir. The original surface water treatment
rule (SWTR) promulgated by the U.S. Environmental Protection Agency (EPA 1989), required the
surface water treatment plant to provide treatment to remove 4-log virus and 3-log Giardia. This
rule has since been updated to include 2-log Cryptosporidium removal as well. SWA projects can
combine the treatment credit achieved prior to the reservoir and at the conventional drinking water
treatment plant to achieve the required pathogen reductions.
A primary goal in the design of the treatment train will be to design an overall system that has
enough credit to achieve the required log removals in the SWA regulations.
5. Regulated Contaminant Limits - As with the GRRP regulations, the recycled water must meet
all current regulatory limits. The inclusion of a RO system will ordinarily keep the product water
quality well below any current regulatory limits; however, it is possible that the San Diego Regional
Water Quality Control Board (RWQCB) may require strict nutrient limits for environmental
reasons, lowering the total nitrogen discharged.
Water Code section 13561 defines Direct Potable Reuse (DPR) as "the planned introduction of recycled
water either directly into a public water system, as defined in Health and Safety Code section 116275, or
into a raw water supply immediately upstream of a water treatment plant." This definition provides a
potential “gap” between SWA and DPR, as certain projects may use a reservoir that is too small to qualify
for the SWA regulations. The adopted SWA regulations address this via an alternatives clause that can
allow for a reduced minimum theoretical retention time of less than 180 days, but no less than 60 days.
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2.3 Direct Potable Reuse
DPR projects are differentiated from IPR based on the absence of an environmental buffer. SWRCB defines
DPR as the planned introduction of recycled water either directly into a public water system (Treated
Drinking Water Augmentation [TDWA]), or into a raw water supply immediately upstream of a water
treatment plant (Raw Water Augmentation [RWA]). No uniform regulations have been established within
the State of California or nationally for DPR. However, AB 574 requires SWRCB to establish a framework
for the regulation of DPR projects by June 1, 2018 and to adopt uniform water recycling criteria for RWA
by 2023. SWRCB published a Proposed Framework for Regulating DPR in California in April 2018. The
two DPR facilities globally that are currently operating (one in Windhoek, Namibia and the other in Big
Spring, Texas) have site-specific permits and treatment requirements set forth by regional regulatory
agencies.
2.3.1 Feasibility of DPR Regulations in California
Senate Bill (SB) 918 directed SWRCB to investigate the feasibility of developing uniform water recycling
criteria for DPR, convene an Expert Panel to study the technical and scientific issues, and provide a final
report to the California State Legislature by December 31, 2016. SB 322 further required that the SWRCB
convene an Advisory Group comprised of utility stakeholders to advise SWRCB and its Expert Panel on
the development of the feasibility report. SB 322 also amended the scope of the Expert Panel to include
identification of research gaps that should be filled to support the development of uniform water recycling
criteria for DPR. The SWRCB DDW released a draft report on the feasibility of DPR in California on
September 8, 2016.
Summary of SWRCB Draft Report
In general, SWRCB found that regulations for DPR projects are attainable and that a common framework
across the various forms of DPR will help avoid discontinuities in the risk assessment and management
approach. The SWRCB clearly indicated that further quantification of reliability is necessary to develop
criteria for DPR. The SWRCB stated that the process for developing criteria for DPR can be initiated as
projects move forward, with a parallel analysis of the knowledge gaps.
The SWRCB outlines recommendations that must be addressed to successfully adopt uniform water
recycling criteria for DPR that are protective of public health. These recommendations were derived in
large part from the Expert Panel report, and are briefly summarized as follows:
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The SWRCB also adopted the Expert Panel and Advisory Group recommendations for non-treatment
barriers, including the following:
•Develop uniform water recycling criteria for DPR concurrently with the six Expert Panel research recommendations to inform the development of criteria.
Concurrent Uniform Criteria Development
•To continue to improve on source control and final water quality monitoring, carry out an ongoing literature review to identify new compounds that may pose health risks from short term exposures, particularly to fetuses and children.
Targeted monitoring for source control and final water quality
•Implement a probabilistic method (Quantitative Microbial Risk Assessment, QMRA) to confirm the necessary removal values for viruses, Cryptosporidium and Giardia, based on a literature review and new pathogen data collected, and apply this method to evaluate the performance and reliability of DPR treatment trains.
Use of QMRA for DPR
•Require monitoring of pathogens in raw wastewater to develop better empirical data on
concentrations and variability.
Pathogen Monitoring in Raw Wastewater
•Investigate the feasibility of collecting raw wastewater pathogen concentration data associated with community outbreaks of disease, and implement where possible.
Outbreak Monitoring
•Identify suitable options for final treatment processes that can provide some “averaging” with respect to potential chemical peaks, particularly for chemicals that have the
potential to persist through advanced water treatment.
Control of Chemical Peaks
•Develop more comprehensive analytical methods to identify unknown contaminants,
particularly low molecular weight compounds in wastewater that may not be removed by advanced treatment and are not detectable with existing monitoring approaches.
Identification of Unknown Contaminants
•Convene technical workgroups to address the knowledge gaps regarding resiliency to assist in developing uniform water recycling criteria for DPR.
Addressing Knowledge Gaps
•SWRCB will continue to work with WE&RF on its DPR Research initiative. SWRCB will serve as an advisor to prioritize projects and serve in its Project Advisory Committees.
DPR Research Initiative
•The SWRCB will partner with other relevant agencies within CalEPA, university
research centers, and water and wastewater research foundations to develop research projects that will advance knowledge relevant to DPR.
Partnering Approach to Research
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1. Advanced training and certification of operators for potable reuse treatment facilities
2. Optimizing wastewater treatment plant performance
3. Enhancing source control/ pretreatment programs
4. Technical, managerial, and financial (TMF) capacity to ensure the success and safety of the project
The Expert Panel report, which is included as an appendix to the SWRCB report, includes the following
specific findings:
• It “is technically feasible to develop uniform water recycling criteria for DPR in California, and
that those criteria could incorporate a level of public health protection as good as or better than
what is currently provided by conventional drinking water supplies and IPR."
• Increasing the reliability of mechanical systems and treatment plant performance will address the
absence of an environmental buffer and the level of protection that it provides in IPR projects.
Several reliability features should be incorporated into DPR projects:
o Providing multiple, independent barriers
o Ensuring the independent barriers represent a diverse set of processes
o Using parallel independent treatment trains
o Providing diversion of inadequately-treated water
o Providing a final treatment step to attenuate any remaining short-term chemical peaks
o Incorporating frequent monitoring of surrogate parameters at each step to ensure treatment
processes are performing properly
o Developing and implementing rigorous response protocols, such as a formal Hazard
Analysis Critical Control Point (HACCP) system
Key Findings
The SWRCB made several statements in the draft report that could have implications to the path forward
for DPR projects in California:
1. Timing: the SWRCB plans to further address knowledge gaps related to reliability prior to
finalizing uniform water recycling criteria for DPR. This indicates that any planned DPR projects
may need to seek site-specific approval from the SWRCB in the absence of a State-wide
framework.
2. Framework for criteria: each form of DPR will have its own unique set of criteria that are possibly
captured within a common framework to avoid discontinuities in the risk assessment. Thus, how a
DPR project is defined could have implications to permitting requirements. The DDW
acknowledges at least three forms of DPR:
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a) Small Reservoir Augmentation: a project delivering recycled water to a surface water
reservoir, with the reservoir providing some benefits, but not the full complement of
benefits provided by SWA. This could include a relatively small reservoir that provides
less than 60 days of “V/Q” retention time.
Figure 2-2: Small Reservoir DPR
b) Raw Water Augmentation (RWA): a project delivering recycled water directly to a
surface water treatment plant or a surface water reservoir that does not provide benefits.
Figure 2-3: RWA
c) Treated Drinking Water Augmentation (TDWA): a project delivering finished water
directly to a public water system's distribution system. The advanced water treatment
facility would also be permitted under the Surface Water Treatment Rule (SWTR) as a
drinking water plant.
Figure 2-4: TDWA (“Flange-to-Flange” DPR)
3. Raw water pathogen monitoring, including during outbreaks and recommendation to
consider incorporating QMRA. The SWRCB approach on establishing pathogen log inactivation
/ removal requirements will directly impact treatment requirements and costs. The language in the
draft report suggests that rather than setting uniform values as with the groundwater replenishment
requirements, the log inactivation / removal requirements could be based on site-specific raw water
pathogen concentrations, or a more robust set of raw water pathogen concentrations for California
that encompasses outbreak data. Those site-specific or worst-case raw water pathogen data would
be used to calculate the required log removal / inactivation requirements to achieve a target finished
water quality, potentially derived from QMRA. Depending on the database of raw water pathogen
data, this approach could result in similar or more stringent requirements for log inactivation /
removal than those established for IPR using injection into the groundwater aquifer as an
environmental buffer.
4. Monitoring and control of ongoing projects. The Expert Panel suggests that a new formal process
be established by the SWRCB to administer periodic review of treatment performance data of
permitted potable reuse projects. This proposed process is not unlike the process for ongoing
monitoring and review of surface water treatment plant operation through surface water monthly
Wastewater
Treatment
Full Advanced
Water
Treatment
Small
Reservoir
Surface
Water
Treatment
Drinking Water
Distribution
System
Wastewater
Treatment
Full Advanced
Water
Treatment
Surface
Water
Treatment
Drinking Water
Distribution
System
Wastewater
Treatment
Advanced Water
Treatment
Drinking Water
Distribution
System
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operating reports (SWMORs), annual reports (e.g., consumer confidence reports), and California
DDW inspections. The SWRCB also indicates a plan to review the state of the science on chemicals
of emerging concern every five years.
5. Start-up and commissioning. The Expert Panel cautioned that the introduction of DPR water into
a public water system be staged to demonstrate reliability before contribution is increased. This
language, if adopted by the SWRCB, has potential implications on the approach for starting up new
DPR facilities.
6. Approach to fill knowledge gaps and incorporate new research findings. Outcomes of ongoing
research and future blue-ribbon panel discussions will influence the criteria for DPR and should be
carefully tracked by any DPR project planning to ensure that the facility design reflects any updated
requirements that are expected to be incorporated in the DPR regulations.
7. DPR projects without reverse osmosis (RO) treatment. The Expert Panel recommended that the
SWRCB consider proposals for DPR projects that do not employ RO. While RO provides a robust
barrier for protozoa, viruses, nitrate, nitrite, TDS, and multiple metals and chemical micro-
constituents, it produces a concentrate stream of up to 20% or more of the raw water production
rate that requires disposal with environmental implications. The SWRCB's approach to establishing
criteria for alternatives to RO will have significant ramifications for the feasibility of DPR projects
that may be unable to readily manage RO concentrate or have other drivers that make RO
unattractive. Figure 5 shows an example of a DPR treatment train without RO as a process, taken
from the Expert Panel report.
Figure 2-5: DPR Treatment Train Example without RO
8. Provision of a final treatment step to "average" out any chemical peaks. The Expert Panel
recommendation for research to identify suitable options for final treatment processes that can
provide some "averaging" with respect to chemical peaks, and any resulting incorporation of that
language in the criteria, will have important implications to the design, cost, and operation of DPR
projects. This point should be carefully considered:
a) If the Expert Panel is concerned with chemicals that pose a chronic health impacts,
"averaging" may or may not result in a health benefit.
Biological Nutrient
Removal + Tert.
Filtration
Ozonation Biological
Activated Carbon Ultrafiltration
UV/H2O2
Biological Aerated
FilterWater StabilizationDisinfection
Chlorine
Drinking Water
Distribution
System
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b) Large storage volumes following chlorine disinfection can result in a risk tradeoff of
increased formation of halogenated disinfection by-products (DBPs).
c) Alternate approaches to "averaging" can result in the same desired benefit. For example, if
the motivation for "averaging" is to reduce peak concentrations in organic chemical
concentrations, a granular activated carbon (GAC) or biologically-active carbon (BAC)
polishing step can further reduce concentrations of these chemicals, rather than simply
averaging. If the motivation for "averaging" is in part to provide additional time to detect
and respond to off-specification water, Salveson et al. (2016) outlines several
recommended approaches to provide that engineered buffer.
9. Consideration and incorporation of non-treatment barriers. The Expert Panel and the SWRCB
recommend incorporation of non-treatment barriers, including: optimization of wastewater
treatment plant operation (WWTP), source control, technical, managerial and financial capacity
(TMF), and operator training and certification. The SWRCB approach to incorporating these non-
treatment barriers in any uniform water recycling criteria for DPR could have implications to:
o WWTP capital improvement projects (CIP) and operational costs;
o Pre-treatment program requirements for monitoring, management, and local limits;
o Industrial discharge options and costs;
o Water utility investment in technical, managerial, and financial capacity; and
o Staffing and training costs for operation of a new DPR facility.
Generally, these non-treatment factors reflect best practices for DPR and are recommended within
the potable reuse industry. However, their potential adoption within State criteria for DPR projects
highlights the importance of planning in advance to ensure that they are addressed as part of a
comprehensive DPR project requiring State of California approval.
10. Research on low molecular weight organics. One of the SWRCB recommendations is that
research be conducted to develop more comprehensive methods to identify low molecular weight
unknown compounds for DPR, including non-targeted analysis as a screening tool. How the
SWRCB proceeds with this may impact monitoring requirements at a minimum for DPR projects,
but could also affect treatment requirements and incorporation of processes that address low
molecular weight compounds. Low molecular weight compounds are perhaps the most challenging
to remove through established treatment processes (e.g., membrane filtration, membrane
desalination, advanced oxidation, granular activated carbon adsorption, biologically active
filtration, and chemical disinfection). Requirements to mitigate these compounds could include
source control strategies as one of the more effective approaches to reduce concentrations in DPR
projects.
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3 Non-Potable Water Reuse in North San Diego County
Recycled water serves as an important local water resource to Southern California, including the North San
Diego County area. Information is provided below on the facilities that receive flows from EWPCF and/or
may be part of the portfolio of options to be developed in this Study. In addition, plans for expansion to the
facilities are also identified based upon the efforts of the North San Diego Water Reuse Coalition
(NSDWRC). This information is summarized in Table 3-1 below.
Table 3-1: Recycled Water Projections
Recycled Water (RW)
Production Facility
Planned Tertiary Treatment
Capacity (mgd)
Projected Peak Summer
Demand, Max. Month (mgd)
2015 2025 2040 2015 2025 2040
Carlsbad WRF 4.0 7.0 7.0 4.0 8.0 10.0
Gafner WRF 1.0 2.5 3.7 0.5 1.0 2.5
Meadowlark WRF 5.0 5.0 7.0 4.0 5.0 6.5
San Elijo WRF 3.0 3.5 3.5 3.0 3.5 3.5
3.1 Carlsbad Water Reclamation Facility
The Carlsbad Municipal Water District (MWD) recycled water system includes the 7.0 mgd Carlsbad Water
Reclamation Facility (CWRF) operated by EWA, 79 miles of pipeline, three booster pumping stations,
three storage tanks, three pressure regulating systems, and two supply sources with pump stations.
Secondary effluent flows from EWPCF are currently sent to CWRF where they are treated to tertiary levels
and recycled. By 2040, the projected peak summer recycled water demand for the City of Carlsbad is
expected to be 10 mgd. The City of Carlsbad’s treatment capacity ownership at EWPCF is 10.26 mgd out
of the total 40.51 mgd liquid capacity (as of the Phase V expansion).
3.2 Leucadia Wastewater District Gafner Water Reclamation Facility
Leucadia Wastewater District (LWWD) wholesales recycled water to the City of Carlsbad for use at the
Omni La Costa Resort and Spa. LWWD owns and operates the Forest R. Gafner WRF, which has a 1 mgd
capacity to treat water to tertiary levels. Secondary effluent is provided to Gafner WRF from EWPCF. In
the short-term, Gafner WRF could be expanded to provide up to an additional 1.5 mgd of recycled water,
increasing its total capacity to 2.5 mgd by 2025. By 2040, the Gafner WRF’s capacity could be increased
to 3.7 mgd for recycled water depending on demands. This expansion would allow LWWD to meet
additional recycled water demands identified through NSDWRC planning efforts. LWWD’s treatment
capacity ownership at EWPCF is 7.11 mgd out of the total 40.51 mgd liquid capacity (as of the Phase V
expansion).
3.3 Vallecitos Water District Meadowlark Water Reclamation Facility
Vallecitos Water District (VWD) provides water, wastewater, and reclamation services to San Marcos, the
community of Lake San Marcos, parts of the cities of Carlsbad, Escondido and Vista, and other
unincorporated areas in north San Diego County, but does not currently retail recycled water to any
customers. VWD owns and operates the 5 mgd Meadowlark WRF and wholesales recycled water to other
agencies (Carlsbad MWD and Olivenhain MWD). However, wastewater flows currently limit production
of recycled water to just under 4 mgd on an average daily basis. Projections show that the average daily
flow will increase to approximately 4.5 mgd in the future. To meet short-term potable reuse demands, VWD
is considering improvements to Meadowlark WRF to provide 1.0 mgd of advanced treatment capacity,
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which may be used for a groundwater replenishment reuse project in the San Marcos Basin. VWD’s
treatment capacity ownership at EWPCF is 7.67 mgd out of the total 40.51 mgd liquid capacity (as of the
Phase V expansion); however, VWD has requested to increase their ownership to 10.06 mgd in the future.
3.4 San Elijo Water Reclamation Facility
San Elijo Joint Powers Authority (JPA) owns and operates San Elijo WRF and approximately 19 miles of
recycled water distribution pipelines and two covered reservoirs. San Elijo WRF is a tertiary treatment
facility that has a design capacity of 5.25 mgd through secondary treatment and a disinfected tertiary
treatment capacity of 3.02 mgd. Secondary-treated wastewater that is not treated to tertiary levels is
discharged to the ocean through the San Elijo Ocean Outfall. The tertiary treatment train at San Elijo WRF
includes microfiltration and reverse osmosis processes. To meet increased recycled water demands, San
Elijo JPA anticipates the need to increase its tertiary treatment capacity by 0.5 mgd (from 3.0 to 3.5 mgd)
by approximately 2025.
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4 Potable Water Reuse Case Studies
A summary of the potable reuse projects in California that were operational as of late 2106 is provided in
Table 4-1. Brief descriptions of the Groundwater Replenishment System, Montebello Forebay Groundwater
Recharge Project, and the Terminal Island Advanced Water Purification Facility are provided in the
following sections.
Table 4-1: Operational Potable Reuse Projects in California (as of 2016)
Agency Project Name
Facility
Start-
up
Potable
Reuse
Type
Current Treatment
Current
Capacity
(mgd)
LACSD, WRD,
LACDPW
Montebello Forebay
Groundwater Recharge
Project
1962 Spreading
Tertiary
(biological, GMF,
disinfection)
50
Orange
County Water
District
Groundwater
Replenishment System 1978 Spreading,
Injection
Purification
(biological, MF, RO,
UV/H2O2)
100
West Basin
Municipal
Water District
West Coast Basin
Seawater Intrusion
Barrier
1992 Injection
Purification
(biological, MF, RO,
UV/H2O2)
17.5
Inland Empire
Utilities
Agency
Chino Basin 2005 Spreading
Tertiary
(biological, GMF,
disinfection)
19
Water
Replenishment
District
Alamitos Barrier 2005 Injection
Purification
(biological, MF, RO,
UV/H2O2)
10
Los Angeles
Bureau of
Sanitation
Dominguez Gap
Seawater Intrusion
Barrier (Terminal Island
AWPF)
2006 Injection
Purification
(biological, MF, RO,
disinfection)
12
Cambria
Community
Services
District
Sustainable Water
Facility at the San
Simeon Well Field and
Percolation Pond
System
2015 Injection
Purification
(biological, MF, RO,
disinfection)
0.5
TOTAL 208
In addition to these operational projects, the map shown in Figure 4-1 also includes the planned potable
reuse projects in California as of July 2018. Notably, three of the five planned SWA projects shown are
located in San Diego County.
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Figure 4-1: Existing and Planned Potable Reuse Projects in California
Source: (WateReuse California, July 2018)
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4.1 Existing Indirect Potable Water Reuse in California
4.1.1 Groundwater Replenishment System
The Orange County Water District's (OCWD) Groundwater Replenishment System (GWRS) is the world's
largest potable water reuse project, producing 100 mgd of purified water that is injected into the local
groundwater basin. Since starting up in the late 1970s, this project has injected more than 188 billion gallons
of purified water into the groundwater basin, later to be extracted for potable water use. Currently, OCWD
is pursuing a final expansion of the GWRS to a total production to 130 mgd.
Figure 4-2: GWRS RO Membranes
4.1.2 Montebello Forebay Groundwater Recharge
The Water Replenishment District (WRD) and the Los Angeles County Sanitation Districts (LACSD) are
partners in the Montebello Forebay Groundwater Recharge Project Tertiary recycled water is recharged
into the local groundwater basin via spreading. Over the last 30+ years, more than 1.45 million acre-feet of
reclaimed water has been placed into spreading basins and percolated down into the aquifer, later to be
extracted for potable water use.
Figure 4-3: Rio Hondo Spreading Grounds, located off-channel
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4.1.3 Terminal Island Advanced Water Purification Facility
The LA Sanitation (LASAN) Terminal Island Advanced Water Purification Facilities (AWPF) provides
highly-purified water to recharge the Dominguez Gap Barrier. Currently the facility is undergoing an
expansion that will increase the plant's capacity from 6 to 12 mgd and will add UV/AOP (UV plus sodium
hypochlorite) for disinfection. The project's expansion will allow Terminal Island AWPF to continue
supplying water to the Dominguez Gap Barrier, as well as to supply reclaimed water to various Los Angeles
Harbor area industrial users and replenish the evaporation losses at Machado Lake.
Figure 4-4: City of Los Angeles Terminal Island AWPF RO Train
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4.2 Planned Direct Potable Water Reuse Projects in California
Within California, multiple agencies are eager to move ahead with direct potable reuse projects. Two
notable examples described below are the San Diego Pure Water program and the VenturaWaterPure DPR
Demonstration Facility.
4.2.1 San Diego Pure Water
As part of its 2015 Point Loma WWTP National Pollutant Discharge Elimination System (NPDES) permit
approval application, the City of San Diego worked with environmental stakeholders to develop a potable
reuse strategy to reduce ocean discharges. This effort resulted in the development of a phased approach for
the San Diego Pure Water Program that is intended to ultimately produce approximately 83 mgd of purified
water by 2035. The initial phase of the Program will produce up to 30 mgd of purified water from the City's
North County Water Reclamation Plant (NCWRP) to augment Miramar Reservoir.
Based on interactions with the independent advisory panel (IAP) and the Division of Drinking Water
(DDW), the City of San Diego has developed an enhanced treatment train concept to ensure reliability of
the purified water discharged to Miramar Reservoir. In a related effort, a Prop. 84 state-funded project, led
by the WateReuse Research Foundation, has been on-going at NCWRP with a 1 mgd demonstration facility
to quantify the reliability of the following potential DPR treatment train:
Ozone → Biologically Activated Carbon → Microfiltration and Ultrafiltration → RO → UV AOP
As part of its first phase of the Pure Water Program, the City is moving forward with the design of this
treatment train for augmenting Miramar Reservoir. Additionally, the project includes conveyance and
discharge of the advanced treated water to Miramar Reservoir, as well as consideration of the integration
of this new supply into the Miramar drinking water treatment plant, a Surface Water Treatment Rule
compliant drinking water filtration plant that will then further treat this recycled water prior to distribution
to consumers.
The Miramar Reservoir is relatively small and has a retention time of approximately two months. According
to early drafts of the SWA regulations, this reduced retention time would have been within the 'gap' between
DPR and SWA. Through significant coordination between the City of San Diego and DDW (e.g., via
weekly meetings through key project development phases), a Draft Engineering Report for the North City
Pure Water Project was submitted in June 2018 with the project defined as SWA and having at least 60
days of retention time in the reservoir. This was in line with the Expert Panel's recommendation to allow
“gap” projects within the SWA regulations via an alternatives clause.
Figure 4-5: San Diego Pure Water Demonstration Facility
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4.2.2 VenturaWaterPure
The goal of the City of Ventura and Ventura Water's VenturaWaterPure demonstration facility was to
document the high quality of purified reclaimed water through extensive water quality testing, and to
understand the impact of blending this purified water with the conventional finished potable water.
Additionally, this demonstration facility provided an educational opportunity for the community.
The VenturaWaterPure demonstration facility was designed to have multiple barriers for both pathogens
and trace pollutants in excess of the treatment required for subsurface (injection) GWA and the anticipated
requirements for DPR. The ~20 gallon per minute process train took filtered secondary effluent from the
Ventura Water Reclamation Facility and treated it through pasteurization, UF, RO, and a UV light advanced
oxidation process using hydrogen peroxide (Figure 4-6). In addition, the RO system was tested with an
online control system using fluorescent tracers to demonstrate a minimum of 3-log removal credit for virus.
Moving forward, a granular activated carbon (GAC) process may be added after RO for an additional barrier
to trace pollutants, and an engineered storage buffer may be added to the treatment train after the UV AOP
to allow for appropriate system monitoring and water quality assurance.
Figure 4-6: City of Ventura DPR Demonstration Facility
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4.3 Existing Potable Reuse Projects Outside of California
Potable water reuse projects have been successfully implemented nationally using a broad range of
treatment and monitoring technology. Three examples of IPR and DPR projects across the United States
are reviewed here.
4.3.1 IPR – SWA in Gwinnett County, Georgia
Gwinnett County Georgia is responsible for the advanced treatment of wastewater prior to discharge into
Lake Lanier. The latest treatment process modifications to the F. Wayne Hill Water Resources Center were
completed in 2005, allowing the advanced treatment of secondary effluent at up to 150 mgd using
microfiltration, pre-ozone, biofiltration, and post-ozone. Water from Lake Lanier is then treated at a
conventional water treatment plant and distributed to customers throughout Gwinnett County.
Figure 4-7: Lake Lanier, Georgia
4.3.2 DPR in Big Spring, Texas
The Colorado River Municipal Water District (CRMWD) is a regional water agency in Texas, serving the
cities of Big Springs, Odessa, Snyder, and others, with a current combined population of about 500,000.
Extreme drought in Texas led the CRMWD to construct the Raw Water Production Facility (RWPF) in Big
Spring, Texas. The RWPF started operating in May 2013, with a production capacity of 2 mgd. The RWPF
uses the same advanced treatment processes as OCWD’s GRWS: MF, RO, and UV advanced oxidation.
After purification, the water from the RWPF is fed into a raw water supply line which blends with other
raw water (up to 50 percent) and is then subjected to treatment at a standard water treatment plant (media
filtration and chlorine disinfection). The City of Big Spring’s surface water treatment plant (SWTP) is the
first downstream user to withdraw from the pipeline. The cities of Snyder, Odessa, Stanton, and Midland
also operate SWTPs that take water downstream of that pipeline.
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Figure 4-8: Colorado River Municipal Water District’s Raw Water Production Facility
A two-year, third-party evaluation of the water quality produced at this facility was recently completed.
Water quality was tested across the treatment train at four major sample events, with test parameters
including enteric virus, Giardia, Cryptosporidium, bacterial indicators, a large suite of CECs
(pharmaceuticals, personal care products, consumer chemicals, flame retardants, steroid hormones,
perfluorinated alkyl substances, conventional and emerging disinfection byproducts) and many other
constituents. The study concluded that the product water met public health standards and was fit to drink
without the additional treatment that occurs at the downstream conventional water treatment plants. The
product water was found to generally be of a better quality than the conventional water supply from Moss
Creek Lake, which has served the CRMWD's customers for many decades (Figure 14).
Figure 4-9: CEC Comparison between DPR Product Water and Existing Source (Moss Creek Lake)
0
1
10
100
1,000
ng/L
AOP Feed Product Water Moss Creek Lake Detection Limits
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4.3.3 DPR High Purity Water Project Demonstration Facility, Oregon
Clean Water Services (CWS) is a water resources management utility in Washington County, Oregon. CWS
has Oregon’s largest water reuse program and is exploring further options to address water needs within
the Tualatin River Watershed. As part of their water reuse program, CWS funded, designed and constructed
a High Purity Water Project DPR Demonstration Facility to purify municipal disinfected secondary effluent
to various levels which would be sufficient for use in a variety of purposes, including semiconductor
processing, agriculture and food crops, product manufacturing, and human consumption. The end goal was
not to immediately produce a purified water for potable use, but to elevate the discussion of water in Oregon
and to allow for a future potable reuse project.
Included in the overall process design were the following advanced water treatment technologies, which,
when combined, provided robust pathogen and pollutant treatment:
Ultrafiltration → RO → UV / AOP → Granular Activated Carbon
These processes were used in series to purify disinfected secondary effluent from CWS’s Forest Grove
Facility (FGF). The testing demonstrated that the FGF effluent provides a very high-quality water absent
of trace pollutants and/or pathogens. As a result, the purified water was deemed suitable for potable use,
public consumption was confirmed, and a single use DPR permit was obtained from the Oregon Department
of Environmental Quality. As a public outreach tool, annual Sustainable Water Challenge/Pure Water Brew
competitions have been held since 2014, in which local brewers enter their beers made with the high purity
water produced by the advanced treatment system (Figure 4-10).
Figure 4-10: Potable Reuse Safety Demonstration Using Understandable Methods (Beer)
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5 Conclusions
As EWA considers opportunities for increasing the reuse of its secondary effluent, the following
considerations drawn from the discussion in this TM can facilitate the determination of timing and
feasibility of various reuse options:
• There is significant experience with successful non-potable water reuse projects in North San Diego
County, which are expected to expand over the next 10-20 years and continue providing a well-
recognized valuable resource to the community.
• Final regulations allow for confident implementation of indirect potable water reuse (IPR) projects
using groundwater recharge, supported by decades of successful project operations in California.
• Regulations for IPR surface water augmentation (SWA) projects were finalized in 2018, and earlier
drafts provided sufficient information to move forward with planning for these types of projects.
• Direct potable water reuse (DPR) has now been determined to be feasible in California by DDW.
Regulations related to RWA are expected by 2023 after further research, expert consultation, and
public engagement to ensure the regulations protect public health while increasing drinking water
supplies. No timeframe has been established for development of regulations related to TDWA.
• Nationally, there are several established and very successful IPR projects, both groundwater
recharge and SWA. Some of these projects have been in operation for over 40 years.
• The most watched potable water reuse project in the U.S. is the CRMWD facility in Big Spring
Texas, where they have been now performing DPR successfully for over three years.
• In the San Diego region, it is expected that the San Diego Pure Water project and the East San
Diego County surface water augmentation project will be one of the pioneers in advancing potable
reuse regulations and public acceptance.
Considering the context of water reuse in California and elsewhere presented in this TM, subsequent TMs
under this Study explore the feasibility of NPR, IPR, and DPR options to allow EWA flexibility to move
forward with one or more options as the regulatory landscape evolves over time.
6 References
Expert Panel on the Development of Water Recycling Criteria for Indirect Potable Reuse through Surface
Water Augmentation and the Feasibility of Developing Criteria for Direct Potable Reuse (Expert Panel)
(2015). Final Panel Meeting Report #5: Surface Water Augmentation – IPR Criteria Review.
Salveson, A., Steinle-Darling, E., Trussell, S., Pecson, B., & Macpherson, L. (2016). Guidelines for
Engineered Storage for Direct Potable Reuse. Water Intelligence Online, 15.
State Water Resources Control Board (SWRCB) (2016). "Investigation on the Feasibility of Developing
Uniform Water Recycling Criteria for Direct Potable Reuse" Public Review Draft.
State Water Resources Control Board (SWRCB), Division of Drinking Water (DDW) (2015). "(Water
Recycling Criteria. Title 22, Division 4, Chapter 3, California Code of Regulations). California State Water
Resources Control Board Division of Drinking Water.
Tchobanoglous, G., J. Cotruvo, J. Crook, E. McDonald, A. Olivieri, A. Salveson, R. S. Trussell. (2015).
Framework for Direct Potable Reuse, WateReuse, American Water Works Association, Water Environment
Federation, and National Water Research Institute.
WateReuse California. (2018). Potable Use Projects Map.
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July 2018 1
Technical Memorandum No. 2
EWA Water Reuse Feasibility Study
Subject: Portfolio of Options
Prepared for: Encina Wastewater Authority
Prepared by: Nathan Chase, P.E. | Woodard & Curran
Reviewed by: Scott Goldman, P.E., BCEE | Woodard & Curran
Date: July 2018 (Draft issued: July 2017)
Table of Contents
1 Introduction ........................................................................................................................................... 3
1.1 Feasibility Study Background ....................................................................................................... 3
1.2 Objectives ..................................................................................................................................... 3
2 Project Feasibility Requirements .......................................................................................................... 3
2.1 General Requirements ................................................................................................................... 3
2.2 EWA-Specific Requirements ........................................................................................................ 3
3 Wastewater Flow Projections................................................................................................................ 4
3.1 Phase V Flow Projections ............................................................................................................. 4
3.2 Updated EWPCF Flow Projections ............................................................................................... 5
4 Treated Effluent Available for Additional Reuse ................................................................................. 6
4.1 Member Agency Recycled Water Demand Projections ................................................................ 6
4.2 Available EWPCF Effluent for Potable Reuse ............................................................................. 6
5 Potential Types of Reuse and Receptors of Advanced Treated Water ................................................. 8
5.1 Groundwater Augmentation Opportunities ................................................................................... 8
5.2 Reservoir Augmentation Opportunities ........................................................................................ 9
5.3 Raw Water Augmentation ........................................................................................................... 10
5.4 Treated Water Augmentation ...................................................................................................... 12
6 Development of Options ..................................................................................................................... 12
7 Qualitative Evaluation of Options ....................................................................................................... 15
7.1 Scoring and Ranking Methodology ............................................................................................ 15
7.2 Feasibility Screening Criteria ...................................................................................................... 15
7.3 Results of Options Screening ...................................................................................................... 16
8 Conclusions ......................................................................................................................................... 18
9 References ........................................................................................................................................... 19
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List of Figures
Figure 3-1: EWPCF Flow Projections to 2040. ............................................................................................ 5
Figure 4-1: Projected 2040 Monthly Flows and Potential for Potable Reuse ............................................... 7
Figure 4-2: Proposed 2040 Peak Summer Flow Schematic .......................................................................... 7
Figure 5-1: Regional Map of SDCWA Aqueduct System and Emergency Storage Project ....................... 11
List of Tables
Table 3-1: EWPCF Liquid Ownership and Current Flow Contribution by Member Agency ...................... 5
Table 4-1: EWA Member Agency Recycled Water Projections to 2040 ..................................................... 6
Table 6-1: Portfolio of Options Summary .................................................................................................. 14
Table 7-1: Feasibility Screening Criteria with Weighting Factors and Scoring Levels .............................. 15
Table 7-2: Scoring and Ranking of Potable Reuse Options ........................................................................ 17
Table 8-1. Most Favorable Options for Further Analysis ........................................................................... 18
Appendices
Appendix A – EWA Member Agency Correspondence
Appendix B – SDCWA Water System Planning Schematic
\\wc\shared\Projects\RMC\IRV\0305 - Encina Wastewater Authority\59 - Water Reuse FS\B. Project Work\2. Portfolio\EWRFS_TM2_Portfolio of Options.docx
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1 Introduction
1.1 Feasibility Study Background
As required by Encina Wastewater Authority’s (EWA) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) will identify a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd).
This Study will focus on developing a portfolio of options for potential reuse projects; identify and analyze
a short list of options; develop an approach to phasing of the preferred water reuse project; identify funding
opportunities; develop a stakeholder involvement plan; and coordinate with EWA member agencies and
other stakeholders to engage with the Study development and recommendations. Ultimately, the Study will
serve to advance EWA’s mission of resource recovery and contribute to sustaining and enhancing the
region’s water environment.
1.2 Objectives
The purpose of this Technical Memorandum (TM) is to define EWA’s portfolio of potential water reuse
options, perform a qualitative evaluation of each option, and define a shortlist of options to be analyzed in
further detail under subsequent TMs in this Study. This TM is organized as follows:
• Project Feasibility Requirements
• Wastewater Flow Projections
• Treated Effluent Available for Additional Reuse
• Potential Types of Reuse Projects and Receptors of Advanced Treated Water
• Development of Options
• Qualitative Evaluation of Options
• Conclusions
2 Project Feasibility Requirements
2.1 General Requirements
In general, a water reuse project is considered feasible when it meets the following overall requirements1:
• Technical: project must be technically feasible, produce high quality water, and achieve sustainable
local supply.
• Regulatory: project must be feasible to permit, protect public health, provide multiple treatment
barriers, and use enhanced monitoring.
• Socioeconomic: project must be accepted by the public, supported by stakeholders, and funded
adequately for capital investments and ongoing operations.
2.2 EWA-Specific Requirements
In addition to generally accepted feasibility requirements, a reuse project must make sense for EWA and
fit within its core functions. As a model of excellence and innovation, EWA is committed to sound planning
1 Adapted from WateReuse DPR Framework Summary Report.
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and investment, protecting public health and the Pacific Ocean, and efficiency and fiscal responsibility.
From EWA’s perspective, for a reuse project to be feasible, it must satisfy the following specific
requirements:
1. Maximize use of available EWPCF effluent year-round: the reuse project must be large enough
to achieve economies of scale, to significantly reduce EWA’s ocean discharges, and to noticeably
advance the sustainability of water resource management in the region.
2. Project cost neutrality (or better) for EWA: the reuse project must ensure fiscal responsibility
to EWA’s Member Agencies and must generate sufficient revenue to offset any costs incurred that
extend beyond EWA’s core functions. To do this, the reuse water must be produced and delivered
at a competitive cost of water with respect to alternatives for the region.
3. Maximize benefits for EWA Member Agencies and Service Area: the reuse project must ensure
that existing and projected recycled water demands for EWA’s Member Agencies will continue to
be met, and that new reuse projects within EWA’s service area will be prioritized if possible.
4. Centralized Advanced Treatment: any potable reuse project will require advanced treatment of
effluent from the EWPCF. For the purposes of this study, it is assumed that any new advanced
treatment facilities will be located on existing EWA property because this provides the most
synergies with existing operations and staff and is consistent with the planned uses for the 28 acres
available at EWA’s South Parcel. Consideration will also be given to locating the advanced
treatment of EWPCF flows at the San Elijo JPA’s Water Reclamation Plant (SEJPA WRP) because
there has been interest expressed by that agency. Other wastewater facilities in North San Diego
County have been excluded, such as the Oceanside San Luis Rey Wastewater Treatment Plant
(SLR) and the Escondido Hale Avenue Resource Recovery Facility (HARRF), because those
facilities have sufficient wastewater and no interest was expressed by those agencies.
5. Maintain EWPCF Sewershed Intact: No consideration was given to diversion of wastewater into
or out of the existing EWA service area. For example, diversion of wastewater away from the
EWPCF and towards the SEJPA WRF was not considered. In addition, diversion of wastewater to
an upstream scalping WRP was also not considered in this study. While these options might be
viable concepts, it is expected that they could only be feasible at a small scale and not maximize
the use of the available local water resources. Therefore, only effluent conveyed from the EWPCF,
or advanced treated water from any new EWA facilities, were considered in the development of
the reuse options.
3 Wastewater Flow Projections
3.1 Phase V Flow Projections
The Phase V Expansion, completed in 2008, was the last major expansion of the EWPCF. Prior to the Phase
V Expansion, EWA spent a great deal of time working with the Member Agencies to project future
wastewater flows and loadings. The results of this effort is a Phase V design influent flow of 40.5 mgd, and
a corresponding solids loading equivalent flow of 43.3 mgd. The difference between the two capacities is
a result of the solids loading from the upstream Meadowlark WRF, which only has a liquid treatment train.
The breakdown of Phase V EWPCF liquid ownership and existing flow contributions from each Member
Agency is shown in Table 3-1.
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Table 3-1: EWPCF Liquid Ownership and Existing Flow Contribution by Member Agency
Agency Phase V Ownership 2017 Average Flows
(mgd) (percent) (mgd) (percent)
Vista 10.67 26.3% 5.88 24.5%
Carlsbad 10.26 25.3% 6.30 26.6%
Buena 3.00 7.4% 1.77 6.7%
Vallecitos 7.67 18.9% 3.51 21.8%
Leucadia 7.11 17.6% 3.82 16.4%
Encinitas 1.80 4.4% 0.97 4.0%
Total 40.51 22.25
3.2 Updated EWPCF Flow Projections
A recent update of the future flow projections to the EWPCF was performed as part of the EWPCF Process
Master Plan (EWA 2016). This update was deemed necessary because of the significant drop in wastewater
flows during the 2011-2017 drought. Population projections were obtained from the San Diego Association
of Governments (SANDAG). An updated unit wastewater generation rate and annual growth rate was
estimated based SANDAG data. This analysis resulted in a range of estimated flows by 2040 between 26
mgd and 31 mgd, which is significantly less than the Phase V design capacity (see Figure 3-1).
Figure 3-1: EWPCF Flow Projections to 2040.
Source: EWA 2016.
A projected annual average daily flow (AADF) of 31.0 mgd by 2040 will be used for this Reuse Study.
Using the higher end of the range of flows assumes that water conservation efforts during the recent drought
may decrease if drought conditions subside in the future, leading to a resumption of a flow growth trend.
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4 Treated Effluent Available for Additional Reuse
Any new reuse project being considered by EWA must be compatible with other current and planned reuse
efforts being undertaken in the region. As an early coordination step, each of the EWA Member Agencies
were contacted to provide input on projected demands. Copies of the letters that were sent to each Member
Agency and their responses are provided in Appendix A – EWA Member Agency Correspondence. It is
assumed that the EWA Member Agencies have determined the maximum amount of cost effective non-
potable reuse within the region, and that a new EWA reuse project will involve some type of potable reuse.
4.1 Member Agency Recycled Water Demand Projections
Based on the responses received, EWA’s Member Agency projections to 2040 include a total of
approximately 12.5 mgd of non-potable recycled water demand to be supplied from the EWPCF, as shown
in Table 4-1. This projection includes 10 mgd to supply the City of Carlsbad’s WRF and 2.5 mgd to supply
Leucadia Wastewater District’s Gafner WRF. It should be noted that Vallecitos Water District’s
Meadowlark WRF obtains its source flow from wastewater diversion upstream of the EWPCF, and thus is
already accounted for in the flow projections for the EWPCF and does not require additional EWPCF
effluent.
Table 4-1: EWA Member Agency Recycled Water Projections to 2040
Recycled Water
Production Facility
Planned Tertiary Treatment
Capacity (mgd)
Projected Peak Summer
Demand, Max. Month (mgd)
2015 2025 2040 2015 2025 2040
Carlsbad WRF 4.0 7.0 10.0 4.0 8.0 10.0
Gafner WRF 1.0 2.5 3.7 0.5 1.0 2.5
Meadowlark WRF 5.0 5.0 7.0 4.0 5.0 6.5
TOTAL (sourced by
EWPCF effluent) 5.0 9.5 13.7 4.5 9.0 12.5
The options developed as part of this Study will allocate flow from the EWPCF to meet the Member
Agency’s 2040 projection of 12.5 mgd of recycled water demands. The remaining flow will be considered
available flow for new potable reuse projects.
4.2 Available EWPCF Effluent for Potable Reuse
Based on the projections to 2040 for EWPCF flows and EWA Member Agency recycled water demands, it
is anticipated that the summertime minimum flow available for potable reuse will be 20.5 mgd. The
summertime minimum was selected to allow the project to operate at capacity year-round, which will
increase the potential to identify a cost effective and feasible project. Assuming typical recovery values for
a conventional full advanced treatment train (i.e., microfiltration with 90% recovery and reverse osmosis
with 85% recovery), this would result in approximately 15.7 mgd of advanced treated water year-round and
approximately 2.8mgd of brine for disposal (as shown on Figure 4-1 and Figure 4-2). Note that this also
assumes that the microfiltration backwash can be added to the nonpotable reuse supply.
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Figure 4-1: Projected 2040 Monthly Flows and Potential for Potable Reuse
Figure 4-2: Proposed 2040 Peak Summer Flow Schematic
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5 Potential Types of Reuse and Receptors of Advanced Treated
Water
This section presents the wide range of opportunities for potable reuse projects within the North San Diego
County region. These are categorized by the potable reuse regulatory framework that would be applicable
for a potential project using EWPCF effluent.
5.1 Groundwater Augmentation Opportunities
5.1.1 San Elijo and San Dieguito Basins
The San Dieguito Valley groundwater basin lies beneath Osuna Valley and San Dieguito Valley in San
Diego County. The basin is naturally recharged by percolation in the San Dieguito River, underflow from
Hodges Dam, percolation from the valley, and underflow from the La Jolla Group Sediments. The
groundwater storage capacity for the basin is estimated to be approximately 50,000 acre-feet. Salinity
concentrations range from up to 3,000 mg/L of total dissolved solids (TDS) in the upper and middle portions
of the basin, to as high as 10,000 mg/L in the lower portion of the basin. The basin primarily overlays the
Olivenhain Municipal Water District (OMWD) service area, as well as part of the SFID/SDWD service
area.
The San Elijo Valley groundwater basin underlies two valleys with Escondido Creek intermittently flowing
through the upper valley and discharging into the San Elijo Lagoon. The basin’s natural recharge source is
primarily percolation in Escondido Creek, with additional smaller recharge contributed by direct
precipitation, underflow from surrounding marine sedimentary units, and percolation of urban runoff.
Groundwater storage capacity for the basin is estimated to be 8,500 acre-feet. This is a narrow and shallow
basin, with average TDS of 1,550 mg/L. Deeper formations have higher TDS of up to 5,000 mg/L.
OMWD is studying the San Elijo/San Dieguito Valley basins for siting of a brackish groundwater desalter
facility near San Elijo Lagoon that could produce up to 1-2 mgd. For San Elijo Valley Basin in particular,
a recent study determined that the feasibility for a groundwater desalter was low due to the thin alluvium
and number of private wells located within the basin (OMWD 2015).
Therefore, for the purposes of this Reuse Study, the San Dieguito Basin will be considered as a potential
location for groundwater augmentation with up to 1 mgd of advanced treated recycled water from the
EWPCF.
5.1.2 San Marcos Basin
The San Marcos Valley groundwater basin lies beneath San Marcos Valley in northwestern San Diego
County, spanning 3.3 square miles. The basin is recharged predominantly by rainfall percolation in the
valley and ephemeral stream flow. TDS levels range between 500 and 750 mg/L, and groundwater quality
is better in the northern part of the basin than in the south (DWR 2003).
Vallecitos Water District has previously studied the San Marcos Valley Groundwater Basin for possible
development. It was estimated in a study done by Todd Engineers in 2005 that the recharge capacity of the
San Marcos Basin is about 4,600 AFY. Development of groundwater in the San Marcos area is constrained
by limited storage, relatively low well yields and poor water quality. Nonetheless, for purposes of this reuse
study the San Marcos Basin will be considered as a potential location for groundwater augmentation with
up to 1 mgd of advanced treated recycled water from the EWPCF.
5.1.3 Mission Basin
The City of Oceanside is investigating the Mission groundwater basin, which runs along the San Luis Rey
River, for groundwater augmentation opportunities using highly treated water from the San Luis Rey WRF.
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The goal is to improve groundwater quality, and thereby also improve the water produced by the Mission
Basin Groundwater Purification Facility (a brackish groundwater desalter), which currently has a capacity
of 6.2 mgd and provides 15% of the City of Oceanside’s water supply. Although this is the largest coastal
basin in the region, it is expected to be fully utilized by the City of Oceanside and therefore will be excluded
from the EWA reuse study’s portfolio of options.
5.2 Reservoir Augmentation Opportunities
5.2.1 Hodges and Olivenhain Reservoirs
Hodges Reservoir was created in 1918 with the construction of Hodges Dam on San Dieguito Creek. The
reservoir and dam are owned by the City of San Diego (since 1925). Hodges Reservoir has a storage
capacity of approximately 30,000 acre-feet, and services the San Dieguito Water District and Santa Fe
Irrigation District. A 21 cfs pipeline carries water from Hodges to the San Dieguito Reservoir, as discussed
in Section 5.2.2 below. In addition, Hodges Dam has historically discharged water from its spillway during
large storm events, which has contributed to groundwater recharge in the San Dieguito basin.
Olivenhain Reservoir is owned by the SDCWA and has a storage capacity of 24,000 acre-feet. A 600 cfs
pump station serves to lift water from Hodges to Olivenhain, with a maximum total design head (TDH) of
800 feet. Energy recovery facilities are used to capture the hydraulic energy when transferring water from
Olivenhain to Hodges. Thus, water is typically moved between the two reservoirs daily to optimize energy
usage in the region. Olivenhain Reservoir can also be filled directly from the Second Aqueduct.
The San Diego County Water Authority (SDCWA) Emergency and Carryover Storage Project consists of
a system of reservoirs, pipelines, and pump stations designed to provide water to the San Diego service area
in an event of an interruption of imported water deliveries (e.g., due to a major earthquake). The project
connects the City of San Diego’s Hodges Reservoir and SDCWA’s Olivenhain Reservoir to store up to
20,000 acre-feet of water in Hodges for emergency use.
Due to water quality concerns in Hodges Reservoir, water from Olivenhain Reservoir must meet DDW
conditions for the blended water quality at the point of connection to the Second Aqueduct raw water
pipeline no. 5, which can restrict the allowable flow from Olivenhain Reservoir. Based on input from the
SDCWA and the City of San Diego, for purposes of this Reuse Study, reservoir augmentation is only
considered for the Olivenhain Reservoir. Hodges and Olivenhain function as a single reservoir and all water
must be conveyed through the Olivenhain reservoir to be distributed to the region. The potential that Hodges
could be full for months at a time eliminated it as a potential receptor of advanced treated water. The
reservoir system is considered large enough to receive all the available advanced treated water from the
EWPCF.
5.2.2 San Dieguito Reservoir
The San Dieguito Reservoir is jointly owned by SFID and SDWD and serves as a raw water storage
reservoir and pretreatment facility for the R.E. Badger Water Filtration Plant (WFP). The reservoir storage
capacity has decreased over time due to decayed plant material build up, solids sent from the Badger WFP,
and sediments from urban and storm water runoff. The current capacity of the reservoir is approximately
800 acre-feet. Based on recent analysis (Trussell, 2015), an existing 30-inch low-pressure pipeline from
SEWRF to the San Dieguito Reservoir could be rehabilitated and used to convey up to 5 mgd or 3,472
gallons per minute (gpm).
The Badger WFP is jointly owned by SFID and SDWD. The plant can treat local water supplied from Lake
Hodges, which is conveyed through the San Dieguito Reservoir for pretreatment, or raw water directly from
the SDCWA Second Aqueduct. The plant was first constructed in 1970 and upgraded in 1993 for a total
treatment capacity of 40 mgd.
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A study performed for SFID, SDWD and SEJPA identified the potential for up to 4 mgd of reservoir
augmentation could be implemented based on the anticipated regulations (Trussell 2016). However, based
upon the expected requirements for surface water augmentation projects, it is anticipated that a maximum
of approximately 3.1 mgd could be accommodated. For purposes of this Reuse Study, the San Dieguito
Reservoir will be considered for Reservoir Augmentation up to 3.1 mgd.
5.2.3 Additional Reservoirs in the Region
Although other reservoirs in the region have been considered in past studies for potable reuse opportunities
(e.g., Lake Wohlford, Lake Dixon), these are not considered feasible for a project using EWPCF effluent.
5.3 Raw Water Augmentation
5.3.1 SDCWA Aqueduct System
SDCWA provides both raw and treated water to serve its member agencies using large-diameter pipelines
that are grouped in two north-south aqueduct alignments (see Figure 5-1 below; for additional detail, see
Appendix B – SDCWA Water System Planning Schematic):
• First Aqueduct consists of the 48-inch diameter Pipelines 1 and 2, which are operated as a single
unit. The northern portion of the First Aqueduct serves to deliver 180 cubic feet per second (cfs) of
treated water from Metropolitan Water District’s (MWD) R.A. Skinner Water Treatment Plant
(WTP). At the connection point with the Crossover Pipeline, the First Aqueduct is refilled with raw
water and provides 190 cfs to various agencies, terminating at the San Vicente Reservoir.
• Second Aqueduct consists of three high pressure (400 psi) pipelines, identified as Pipelines 3, 4,
and 5, which are operated independently. All three pipelines run from the MWD Delivery Point,
six miles south of the county boundary, to the Twin Oaks Valley WTP, and continue south to a
point where the Second Aqueduct crosses Interstate 15 in the Mira Mesa area. Their design
characteristics are summarized below:
o Pipeline 3: 72-inch diameter, 280 cfs, terminates at the Lower Otay Reservoir
o Pipeline 4: 90-inch diameter, 470 cfs, terminates at the Lower Otay Reservoir
o Pipeline 5: 96-inch diameter, 500 cfs, terminates just north of I-15
Pipelines 3, 4, and 5 operate differently between different reaches of the aqueduct, as summarized below:
• Pipeline 3 conveys treated water in the reach from the Twin Oaks Valley Diversion Structure to the
Interstate 15 (south of the Miramar Vent). North of San Marcos, 5.5 miles of Pipeline 3 have been
re-purposed to convey water from the Carlsbad Desalination Plant to the Twin Oaks Valley
Diversion Structure. South of San Marcos, Pipeline 3 continues as a gravity flow treated water
pipeline at 200 cfs until it reaches its connection with the Ramona Pipeline.
• Pipeline 4 conveys treated water from its initial MWD delivery point to the Miramar Vent; south
of the Miramar Vent, it branches off to provide treated water to South County, and also
interconnects with Pipeline 3 to provide raw water.
• Pipeline 5 is used for raw water only. It conveys 636 cfs of raw water to the R.E. Badger and David
C. McCollom WTPs.
For purposes of this Study, Pipeline 5 will be considered an option for raw water augmentation up to the
full amount of advanced treated water that is available from EWPCF. It is assumed that sufficient blend
water would be available within Pipeline 5 based on SDCWA’s current operations.
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Figure 5-1: Regional Map of SDCWA Aqueduct System and Emergency Storage Project
Source: Civil Engineering Magazine, November 2016.
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5.3.2 Twin Oaks Valley Water Treatment Plant
The Twin Oaks Valley WTP was completed in 2008 as the first treatment plant built by SDCWA. The plant
is located adjacent to SDCWA’s Second Aqueduct north of San Marcos, with a treated water capacity of
100 mgd. The Twin Oaks Valley WTP primarily treats raw imported water delivered from the State Water
Project or Colorado River. In addition, the Twin Oaks WTP is one of the locations where SDCWA can
blend and distribute the desalinated product water from the Carlsbad Desalination Plant throughout the
region.
For purposes of this reuse study, Twin Oaks Valley will not be considered an option for raw water
augmentation using advanced treated water that is available from EWPCF. The distance to the Twin Oaks
Valley WTP is further than the raw water aqueducts and offers little to no advantage over the pipeline.
5.3.3 Carlsbad Desalination Plant
Poseidon Water owns the Claude “Bud” Lewis Carlsbad Desalination Plant (CDP), a 54 mgd desalination
plant adjacent to the Encina Power Station in Carlsbad. Potable water produced at the CDP is delivered to
the SDCWA at the property boundary of the treatment facility. SDCWA has responsibility for distribution
of the potable water, which is first pumped from the desalination pump station into the desalinated water
conveyance pipeline. From there, the desalinated water can be delivered to Pipelines 3, 4, and/or the Tri-
Agency Pipeline (serving Vallecitos Water District, Vista Irrigation District, and Carlsbad Municipal Water
District, as well as the City of Oceanside).
For purposes of this reuse study, the CDP will be considered an option for raw water augmentation up to
the full amount of advanced treated water that is available from EWPCF. For raw water augmentation, this
would involve blending the advanced treated water from the EWPCF with the ocean water prior to the
desalination treatment step.
5.4 Treated Water Augmentation
5.4.1 SDCWA Desalinated Water Pipeline
The Carlsbad desalinated water conveyance pipeline is considered an east-west branch of the Second
Aqueduct. It is 10 miles long and has a 54-inch diameter. Since the CDP started operations in late 2015, an
average of approximately 50 mgd has been supplied to the SDCWA and its Member Agencies. Additional
pipeline capacity is available up to a total of approximately 83 mgd.
At the location where the desalinated water pipeline ties into the Second Aqueduct, the minimum HGL in
Pipelines 3 and 4 is approximately 979 ft (equal to the invert elevation of the San Marcos Vents).
For purposes of this reuse study, the SDCWA Desalinated Water pipeline will be considered an option for
treated water augmentation using advanced treated water that is available from EWPCF.
5.4.2 SDCWA Second Aqueduct Pipelines 3-4
For purposes of this Reuse Study, the Second Aqueduct treated water pipelines in the vicinity of the EWPCF
(Pipelines 3 and 4) will not be considered an option for treated water augmentation because the distance
from the EWPCF to Pipeline 3 is further than that to the Desalination Pipeline and is not expected to offer
any significant advantage.
6 Development of Options
Based on the various potable reuse opportunities described in the previous section, the following nine
options were identified as EWA’s Portfolio of Options for this Reuse Study. Note that all options include
the baseline assumption of reserving 12.5 mgd for nonpotable reuse by EWA Member Agencies. Brine
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losses are also accounted for, depending on whether the reverse osmosis treatment step includes seawater
(assumed 60% recovery and 40% brine) or not (assumed 85% recovery and 15% brine).
A. Carlsbad Desalination Plant (CDP) Influent
• 11.1 mgd of potable reuse through raw water augmentation of the CDP source water
B. CDP Product Water
• 15.7 mgd potable reuse through treated water augmentation of the CDP finished water
C. Olivenhain Reservoir
• 15.7 mgd potable reuse through reservoir augmentation of the Olivenhain Reservoir
D. San Dieguito Reservoir and Olivenhain Reservoir
• 15.7 mgd potable reuse through the following:
o Groundwater augmentation of the San Dieguito Valley groundwater basin (up to 2 mgd)
o Reservoir augmentation of the San Dieguito Reservoir (up to 3.1 mgd)
o Reservoir augmentation of the Olivenhain Reservoir (9.7 mgd to 15.7 mgd)
E. San Dieguito Reservoir and CDP Influent
• 12.6 mgd potable reuse through the following:
o Groundwater augmentation of the San Dieguito Valley groundwater basin (up to 2 mgd)
o Reservoir augmentation of the San Dieguito Reservoir (up to 3.1 mgd)
o Raw water augmentation of the CDP source water (7.5 mgd to 12.6 mgd)
F. San Dieguito Reservoir and CDP Product Water
• 15.7 mgd potable reuse through the following:
o Groundwater augmentation of the San Dieguito Valley groundwater basin (up to 2 mgd)
o Reservoir augmentation of the San Dieguito Reservoir (up to 3.1 mgd)
o Treated water augmentation of the CDP finished water (9.7 to 15.7 mgd)
G. San Dieguito Reservoir and Second Aqueduct
• 15.7 mgd potable reuse through the following:
o Groundwater augmentation of the San Dieguito Valley groundwater basin (up to 2 mgd)
o Reservoir augmentation of the San Dieguito Reservoir (up to 3.1 mgd)
o Raw water augmentation of the Second Aqueduct, Pipeline No. 5 (9.7 to 13.7 mgd)
H. Second Aqueduct and San Marcos Basin
• 15.7 mgd potable reuse through the following:
o Groundwater augmentation of the San Marcos groundwater basin (up to 2 mgd)
o Raw water augmentation of the Second Aqueduct, Pipeline No. 5 (13.7 to 15.7 mgd)
I. Twin Oaks WTP Influent and San Marcos Basin
• 15.7 mgd potable reuse through the following:
o Groundwater augmentation of the San Marcos groundwater basin (up to 2 mgd)
o Raw water augmentation of the Twin Oaks WTP source water (13.7 to 15.7 mgd)
Table 6-1 summarizes the portfolio of options and the associated 2040 peak summer production.
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Table 6-1: Portfolio of Options Summary
Footnotes
1. Assumed available secondary effluent flow from EWPCF: 31.0 mgd
2. Assumed secondary effluent sent to AWPF as source water: 20.5 mgd
3. Assumed recovery from MF process: 90%
4. Assumed recovery from AWT RO process: 85%
5. Assumed recovery from seawater desalination process: 60%
6. Assume that all potable reuse options require MF and RO (at AWT or at desalination plant), and assume that MF backwash can be recovered for NPR.
NPR
Recycled
Water
Ground-
water
Large
Res.
Small
Res.
Source
Water
Treated
Water SE Brine
A Carlsbad Desalination Plant (CDP) Influent 12.5 - - - 11.1 - 0 7.4 11.1 23.6
B CDP Product Water 12.5 - - - - 15.7 0 2.8 15.7 28.2
C Olivenhain Reservoir 12.5 - 15.7 - - - 0 2.8 15.7 28.2
D San Dieguito Reservoir + Olivenhain Reservoir 12.5 2.0 10.6 3.1 - - 0 2.8 15.7 28.2
E San Dieguito Reservoir + CDP Influent 12.5 2.0 - 3.1 7.5 - 0 5.9 12.6 25.1
F San Dieguito Reservoir + CDP Product Water 12.5 2.0 - 3.1 - 10.6 0 2.8 15.7 28.2
G San Dieguito Reservoir + 2nd Aqueduct (Raw)12.5 2.0 - 3.1 10.6 - 0 2.8 15.7 28.2
H Second Aqueduct (Raw) + San Marcos Basin 12.5 2.0 - - 13.7 - 0 2.8 15.7 28.2
I Twin Oaks WTP Influent + San Marcos Basin 12.5 2.0 - - 13.7 - 0 2.8 15.7 28.2
Option Description DPR
Total
Potable
Reuse
(mgd)
Option
ID
Total
Reuse
(mgd)
IPR
Projected 2040 Peak Production (mgd)
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7 Qualitative Evaluation of Options
7.1 Scoring and Ranking Methodology
A set of criteria was developed to allow for an initial screening of each option in EWA’s Portfolio of
Options prior to embarking on a more detailed evaluation of the top preferred options, which will include
capital and operating cost analyses. For each criterion, a weighting factor was assigned and scoring levels
were selected based on the expected range and relative impact on project feasibility. The weighting and
scoring methodology is summarized as follows:
1. Assign a Weighting Factor to each Criterion (on a scale of 1-10), where a higher weight means
higher impact on project feasibility.
2. Define Scoring Levels within each Criterion (on a scale of 0-4), where a higher score means the
project is more feasible.
3. Select appropriate scoring for each option across all criteria.
4. Multiply scores by their associated weighting factors to obtain Option total score.
5. Rank Options by total score.
For options with multiple potable reuse types (e.g., Option E contains both DPR and IPR), points are
allocated to each project based on the criteria and are weighted by flow.
7.2 Feasibility Screening Criteria
The five feasibility screening criteria used are shown in Table 7-1 below, along with key considerations
and associated weighting and scoring.
Table 7-1: Feasibility Screening Criteria with Weighting Factors and Scoring Levels
Screening Criteria Weight Score Description of Scoring Levels
Regulatory Certainty and Permitting Effort
Considerations:
-Status of regulations in California and
expected future requirements.
-Ease of approval and precedents to follow.
6
4 IPR (groundwater or surface water)
3 DPR - Source Water (for SWTP)
2 N/A
1 DPR - Source Water (for desalination)
0 DPR - Treated Water (flange-to-flange)
Treatment and Engineered Storage
Considerations:
-Knowledge of advanced treatment and
engineered storage requirements.
-Operational complexity and potential impacts
to EWPCF.
5
4 FAT for IPR (groundwater or surface water)
3 FAT for DPR (source water augmentation)
2 N/A
1 FAT for DPR (treated water augmentation)
0 FAT for DPR (for desalination)
Operations
Considerations:
-Regional demand for raw/treated water
(considering seasonality).
-Integration with reservoir operations and
groundwater management.
-Brine management and disposal for
desalination.
5
4 No seasonal limitations
3 Seasonal limitations (e.g., demand for treated water)
2 Wet-weather limitations (e.g., reservoir freeboard)
1 Integration with desalination facilities & increased
brine disposal
0 Groundwater recharge facilities/operations
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Screening Criteria Weight Score Description of Scoring Levels
Conveyance Infrastructure
Considerations:
-Pipeline length, alignment constraints,
pumping facilities, pumping requirements.
10
4 <5 miles
3 5-15 miles | <500 ft ΔHGL
2 5-15 miles | >500 ft ΔHGL
1 >15 miles | <500 ft ΔHGL
0 >15 miles | >500 ft ΔHGL
Stakeholders and Institutional Challenges
Considerations:
-Benefits to EWA member agencies.
-Institutional challenges related to quantity and
type of stakeholders.
-Public acceptance of regional IPR/DPR option.
3
4 EWA Member Agencies only
3 EWA + 1 stakeholder group
2 EWA + 2 stakeholder groups
1 EWA + 3 stakeholder groups
0 EWA + 4 stakeholder groups
7.3 Results of Options Screening
Based upon the methodology described above, each of the nine options within EWA’s Portfolio of Options
was scored. This led to the ranking of options by score, as shown in Table 7-2.
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Table 7-2: Scoring and Ranking of Potable Reuse Options
Footnote
1. For options with multiple potable reuse types, points are allocated to each project based on the criteria and are weighted by flow.
CDP
Influent
CDP
Product
Water
Olivenhain
Reservoir
San
Dieguito
Res. +
Olivenhain
Res.
San
Dieguito
Res. + CDP
Influent
San
Dieguito
Res. + CDP
Product
Water
San
Dieguito
Res. + 2nd
Aqueduct
(Raw)
Second
Aqueduct
(Raw) + San
Marcos
Twin Oaks
WTP
Influent +
San Marcos
Screening Criteria Weight Score Description of Scoring Levels A B C D E F G H I
4 IPR (groundwater or surface water)
3 DPR - Source Water (for SWTP)
2 N/A
1 DPR - Source Water (for desalination)
0 DPR - Treated Water (flange-to-flange)
4 FAT for IPR (groundwater or surface water)
3 FAT for DPR (source water augmentation)
2 N/A
1 FAT for DPR (treated water augmentation)
0 FAT for DPR (for desalination)
4 No seasonal limitations
3 Seasonal limitations (e.g., demand for treated water)
2 Wet-weather limitations (e.g., reservoir freeboard)
1 Integration with desalination facilities & increased brine disposal
0 Groundwater recharge facilities/operations
4 <5 miles
3 5-15 miles | <500 ft ΔHGL
2 5-15 miles | >500 ft ΔHGL
1 >15 miles | <500 ft ΔHGL
0 >15 miles | >500 ft ΔHGL
4 EWA Member Agencies only
3 EWA + 1 stakeholder group
2 EWA + 2 stakeholder groups
1 EWA + 3 stakeholder groups
0 EWA + 4 stakeholder groups
57 69 60 67 68 74 87 81 60
9 4 8 6 5 3 1 2 7
6
Operations 5
3
2.13
Stakeholders and
Institutional
Challenges
Regulatory
Certainty and
Permitting Effort
1
Conveyance
Infrastructure 10
4
5
Treatment and
Engineered
Storage
2
2
3
4 1.6 2.0 3.1
2.8 3.5
1 2
1.6
3.3
3.5
2.6
2
1
1
4 0
4
0
Total Weighted Score
Rank
4
0
2
3.1
4 2.2 3.1
1.0 3.6 3.7 2.0
3.1
2.6
1.3 3.3
Portfolio of Options Scoring
0.4
3
1
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July 2018 18
8 Conclusions
Based on the results from the screening evaluation, the following are the three most favorable options that
will be carried into TM3 for further analysis to determine feasibility and identify the preferred project:
1. Option F: San Dieguito Reservoir and CDP Product Water
2. Option G: San Dieguito Reservoir and Second Aqueduct (Raw Water Pipeline 5)
3. Option H: Second Aqueduct (Raw Water Pipeline 5) and San Marcos Basin
Table 8-1 summarizes key aspects of each of these options, including the projected flows considered for
each of the potable reuse receptors selected for this Reuse Study (as described in Section 5 above).
Table 8-1. Most Favorable Options for Further Analysis
Potable Reuse
Receptor
Key
Stakeholders
Form of
Potable Reuse Option F Option G Option H
San Dieguito
Groundwater Basin
Olivenhain
MWD
Groundwater
Augmentation 2 mgd 2 mgd -
San Marcos
Groundwater Basin Vallecitos WD Groundwater
Augmentation - - 2 mgd
San Dieguito
Reservoir
SEJPA/ SFID/
SDWD
Surface Water
Augmentation 3.1 mgd 3.1 mgd -
Olivenhain and
Hodges Reservoirs
SDCWA, City
of San Diego
Surface Water
Augmentation - - -
Second Aqueduct
(Pipeline 5) SDCWA Raw Water
Augmentation - 10.6 mgd 13.7 mgd
Carlsbad Desalination
Plant Finished Water SDCWA Treated Water
Augmentation 9.7 mgd - -
Twin Oaks Valley
WTP SDCWA Raw Water
Augmentation - - -
Carlsbad Desalination
Plant Influent
Poseidon,
SDCWA
Raw Water
Augmentation - - -
Potential Phase 1 Potable Reuse
TOTAL POTABLE REUSE
5.1 mgd
15.7 mgd
5.1 mgd
15.7 mgd
N/A
15.7 mgd
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July 2018 19
9 References
DWR, 2003. Bulletin 118: California’s Groundwater. October 2003.
EWA, 2016. Process Master Plan for the EWPCF. Prepared for Encina Wastewater Authority. Prepared
by Carollo Engineers. November 2016.
OMWD, 2015. San Elijo Valley Groundwater Project. Prepared for Olivenhain Municipal Water District.
Prepared by Stoney-Miller Consultants, Inc. February 2015.
SDCWA, 2014. Final 2013 Regional Water Facilities Optimization and Master Plan Update. Prepared for
San Diego County Water Authority. Prepared by CH2MHill/Black & Veatch. March 2014.
Trussell, 2016. Santa Fe Irrigation District, San Dieguito Water District, and San Elijo Joint Powers
Authority Potable Reuse Feasibility Study. Trussell Technologies, Inc. in association with RMC Water
and Environment, March 2016.
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TM2: Portfolio of Options
Appendix A – EWA Member Agency Correspondence
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Attached is a request for confirmation of water reuse projections for the City of Vista and the Buena
Sanitation District. As we move forward with this water reuse feasibility study we want to make sure we
capture all potential water reuse for each of EWA’s member agencies and key stakeholders to ensure
compatibility and alignment. Thanks in advance for your help!
Hard copy to follow.
Best,
Mike
Michael F. Steinlicht
General Manager
Encina Wastewater Authority
From: Brian Smith [mailto:BSmith@vidwater.org]
Sent: Thursday, November 3, 2016 7:08 AM
To: 'mikes@encinajpa.com'
Cc: 'ealex@ci.vista.ca.us'; Scott Goldman; Don Smith; Randy Whitmann
Subject: FW: Confirmation of Water Reuse Projections
Mike,
I am Brian Smith, Director of Engineering at the Vista Irrigation District. I am responding to an email you
sent to Don Smith at our office.
We do not have any immediate plans for any reuse or recycled water projects. All potential recycled
projects for our District are included in the North San Diego Water Reuse Coalition’s Facilities Plan.
If you have any questions or need additional information please feel free to contact Randy Whitman or
myself.
Sincerely,
Brian Smith
Director of Engineering
Vista Irrigation District
1391 Engineer St.
Vista, CA 92081
(760) 597-3113
bsmith@vidwater.org
From: Mike Steinlicht [mailto:mikes@encinajpa.com]
Sent: Monday, October 31, 2016 8:16 AM
To: Don Smith
Cc: Scott Goldman; Nathan Chase; 'Elmer Alex (ealex@ci.vista.ca.us)'
Subject: Confirmation of Water Reuse Projections
Good Morning Don,
Sept. 27, 2022 Item #10 Page 89 of 279
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From: Paul Bushee <PBushee@lwwd.org>
Sent: Monday, October 31, 2016 9:37 AM
To: Mike Steinlicht
Cc: Scott Goldman; Nathan Chase
Subject: RE: Confirmation of Water Reuse Projections
Mike:
Thanks for forwarding the information. All the flow numbers look accurate for LWD. I don’t this would
impact EWA’s study, but the only discrepancy I could see was that we would have to build a pump
station and pipeline to OMWD or Carlsbad if we increase our capacity to 2.5 mgd in 2025.
Thanks,
Paul
Paul J. Bushee
General Manager
Leucadia Wastewater District
1960 La Costa Avenue
Carlsbad, CA 92009
Ph: (760) 753-0155
Fax: (760) 753-3094
Email: pbushee@lwwd.org
Web: www.lwwd.org
From: Mike Steinlicht [mailto:mikes@encinajpa.com]
Sent: Friday, October 28, 2016 11:01 AM
To: Paul Bushee <PBushee@lwwd.org>
Cc: Scott Goldman <sgoldman@rmcwater.com>; Nathan Chase <nchase@rmcwater.com>
Subject: Confirmation of Water Reuse Projections
Good Morning Paul,
Attached is a request for confirmation of water reuse projections for the Leucadia Wastewater
District. As we move forward with this water reuse feasibility study we want to make sure we capture
all potential water reuse for each of EWA’s member agencies to ensure compatibility and
alignment. Thanks in advance for your help!
Hard copy to follow.
Best,
Mike
Sept. 27, 2022 Item #10 Page 93 of 279
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Sept. 27, 2022Item #10 Page 96 of 279
From: Terry Smith <Terry.Smith@carlsbadca.gov>
Sent: Tuesday, November 22, 2016 12:48 PM
To: Mike Steinlicht
Cc: Scott Goldman; Nathan Chase; Wendy Chambers
Subject: RE: Confirmation of Water Reuse Projections
Mike,
I have reviewed the attached letter and agree with the projections you have shown for the City of
Carlsbad. I have no additional comments.
Thanks,
Terry L. Smith, PE
Engineering Manager / District Engineer
Public Works – Utilities Engineering
City of Carlsbad
5950 El Camino Real
Carlsbad, CA 92008
www.carlsbadca.gov
Direct Line 760.603.7354
Terry.Smith@carlsbadca.gov
From: Mike Steinlicht [mailto:mikes@encinajpa.com]
Sent: Friday, October 28, 2016 11:01 AM
To: Terry Smith <Terry.Smith@carlsbadca.gov>; Wendy Chambers <Wendy.Chambers@carlsbadca.gov>
Cc: Scott Goldman <sgoldman@rmcwater.com>; Nathan Chase <nchase@rmcwater.com>
Subject: Confirmation of Water Reuse Projections
Good Morning Terry, Wendy,
Attached is a request for confirmation of water reuse projections for the City of Carlsbad. As we move
forward with this water reuse feasibility study we want to make sure we capture all potential water
reuse for each of EWA’s member agencies to ensure compatibility and alignment. Thanks in advance for
your help!
Sept. 27, 2022 Item #10 Page 97 of 279
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EWA Water Reuse Feasibility Study
TM2: Portfolio of Options
Appendix B – SDCWA Water System Planning Schematic
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CAPITAL IMPROVEMENT
PROGRAM
WATER SYSTEM PLANNING SCHEMATIC
AQUEDUCTS, FLOW CONTROL FACILITIES
AND GRADIENT CONTROL STRUCTURES
STATUS: AS OF DECEMBER 2016
NOTES
SYMBOLS
ABBREVIATIONS
LEGEND
LAKE MORENA
50,200 ACRE-FEET
EL. 3039.4
LOVELANDRESERVOIR
25,400 ACRE-FEET
EL. 1355.0
LOWER OTAY
RESERVOIR49,500 ACRE-FEETEL. 484.7
LAKE MURRAY
4,820 ACRE-FEET
EL. 536.5
EL CAPITAN RESERVOIR113,000 ACRE-FEET
EL. 750.00
LAKE CUYAMACA8,190 ACRE-FEET
EL. 4635.6
LAKE JENNINGS9,790 ACRE-FEETEL. 700.00
STARVATION
MOUNTAINRESERVOIR
RMWD
30 ACRE-FEET
LAKE RAMONA12,000 ACRE-FEET
EL. 1341.00
LAKE POWAY
3,320 ACRE-FEET
EL. 938.00
SWEETWATER
RESERVOIR27,700 ACRE-FEETEL. 237.00
SUTHERLANDRESERVOIR
29,700 ACRE-FEET
EL. 2057.00
LAKE DIXON2,610 ACRE-FEET
EL. 1043.50
LAKE WOLHFORD
6,940 ACRE-FEET
EL. 1480.21
ESCONDIDO
CANAL 60 CFS
SAN LUISREY RIVER
HENSHAWRESERVOIR
53,400 ACRE-FEET
EL. 2690.00
TURNERRESERVOIR1,730 ACRE-FEET
EL. 1071.00
OLIVENHAIN RESERVOIR24,700 ACRE-FEETSPILLWAY EL. 1080.50
LAKE HODGES
30,250 ACRE-FEETEL. 315.00
SAN VICENTE RESERVOIR249,350 ACRE FEET
EL. 766.00
LAKE MIRAMAR
7,180 ACRE-FEET
EL. 714.00
RED MOUNTAINRESERVOIR
1,335 ACRE-FEETEL. 1140.00
SAN DIEGUITO
RESERVOIR
883 ACRE-FEETEL. 250.00
BARRETT LAKE37,900 ACRE-FEETEL. 1607.0
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Attachment 3 - TM3: Preferred Project Identification
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July 2018 1
Technical Memorandum No. 3
EWA Water Reuse Feasibility Study
Subject: Preferred Project Identification
Prepared For: Encina Wastewater Authority
Prepared by: Nathan Chase, P.E.; Kraig Erickson, P.E. | Woodard & Curran
Samantha Bear; Brett Faulkner, P.E. | Trussell Technologies
Andrea F. Corral, Ph.D. | Carollo Engineers
Michael Welch, Ph.D., P.E.
Reviewed by: Sunny Huang, P.E. and Scott Goldman, P.E., BCEE | Woodard & Curran
Shane Trussell, Ph.D., P.E., BCEE | Trussell Technologies
Andrew Salveson, P.E. | Carollo Engineers
Date: July 2018 (Draft: January 2018)
Table of Contents
1 Introduction ........................................................................................................................................... 5
Feasibility Study Background ....................................................................................................... 5
Objectives ..................................................................................................................................... 5
2 Wastewater Treatment Plant Improvements ......................................................................................... 7
EWPCF Treatment Upgrades ........................................................................................................ 7
Preliminary Layout of Improvements ......................................................................................... 13
Conceptual Costs for EWPCF Improvements ............................................................................. 15
3 Advanced Water Treatment Concepts ................................................................................................ 17
Overview ..................................................................................................................................... 17
Treatment Technologies .............................................................................................................. 17
Proposed Treatment Trains ......................................................................................................... 21
Unit Process Monitoring ............................................................................................................. 23
Facility Planning and Conceptual Layouts ................................................................................. 26
Conceptual Costs for Advanced Treatment ................................................................................ 51
4 Conveyance Concepts ......................................................................................................................... 53
Introduction ................................................................................................................................. 53
Option F – North ......................................................................................................................... 55
Option G – South ........................................................................................................................ 58
Option H - East ........................................................................................................................... 62
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Conceptual Costs for Conveyance .............................................................................................. 65
5 Purified Water Receptor Integration Concepts ................................................................................... 67
Groundwater Augmentation ........................................................................................................ 67
Surface Water Augmentation ...................................................................................................... 68
Raw Water and Treated Drinking Water Augmentation ............................................................. 69
6 Permitting Considerations and Brine Disposal ................................................................................... 73
Permitting Overview ................................................................................................................... 73
Groundwater Augmentation ........................................................................................................ 77
Surface Water Augmentation ...................................................................................................... 78
Raw Water Augmentation ........................................................................................................... 86
Brine Disposal ............................................................................................................................. 87
7 Conceptual Cost Analysis ................................................................................................................... 89
Cost Opinion Methodology ......................................................................................................... 89
Costs by Option ........................................................................................................................... 91
8 Conclusions ......................................................................................................................................... 95
References ................................................................................................................................................... 96
Appendix A – Conceptual Cost Analysis Tables ...................................................................................... 101
List of Figures
Figure 2-1: Projected EWPCF Diurnal Flow Curve and Flow Equalization Volume .................................. 8
Figure 2-2: Preliminary site layout for new facilities at EWPCF ............................................................... 14
Figure 3-1: Advanced Treatment Train Options. ........................................................................................ 22
Figure 3-2: Representative Layout of the FAT AWTF on EWA’s South Parcel. ...................................... 34
Figure 3-3: Representative Layout of the O₃/BAF + FAT AWTF on EWA’s South Parcel (Far View). .. 46
Figure 3-4: Representative Layout of the O₃/BAF + FAT + WTP on EWA’s South Parcel (Far View). .. 49
Figure 3-5: Representative Layout of the O₃/BAF + FAT AWTF Expansion (25 mgd) on EWA’s South
Parcel. ................................................................................................................................................. 51
Figure 4-1: Pumping Requirements Summary ............................................................................................ 54
Figure 4-2: Option F - Carlsbad Desalination Plant Augmentation Alignment .......................................... 56
Figure 4-3: Option F - Carlsbad Desalination Plant Augmentation HGL ................................................... 57
Figure 4-4: Option G Alignment Analysis .................................................................................................. 59
Figure 4-5: Option G - San Dieguito Reservoir, Groundwater Basin & SDCWA Second Aqueduct
Augmentation HGLs .......................................................................................................................... 60
Figure 4-6: Option H Alignment. ................................................................................................................ 63
Figure 4-7: Option H - San Marcos Groundwater Basin & SDCWA Aqueduct #2 Augmentation HGL .. 64
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Figure 7-1: Capital Cost Summary for Options F, G, and H. ..................................................................... 91
Figure 7-2: Cost of Water Summary for Options F, G, and H. ................................................................... 92
List of Tables
Table 2-1: Average Influent and Primary Effluent Strength for 2011 - 2012 and 2016 ............................... 9
Table 2-2: Modeling Results Summary ...................................................................................................... 10
Table 2-3: Aeration Basin Retrofit .............................................................................................................. 12
Table 2-4: Dimensions of Proposed Facilities ............................................................................................ 14
Table 2-5: Preliminary Estimate of Increase in O&M Cost with NDN ...................................................... 16
Table 3-1: Potable Reuse Pathogen Reduction Requirements (from source water to potable water). ........ 23
Table 3-2: Expected Performance of Treatment Train “a” for Groundwater Augmentation. ..................... 23
Table 3-3: Expected Performance of Treatment Train “a” for Surface Water Augmentation. ................... 24
Table 3-4: Expected Performance of Treatment Train “b” for Raw Water Augmentation. ....................... 24
Table 3-5: Expected Performance of Treatment Train “c” for Treated Drinking Water Augmentation. ... 25
Table 3-6: CCPs for an AWTF. .................................................................................................................. 26
Table 3-7: UF System Design Parameters .................................................................................................. 26
Table 3-8: RO System Design Parameters .................................................................................................. 30
Table 3-9: UV/AOP Design Parameters ..................................................................................................... 32
Table 3-10: FAT AWTF Footprint. ............................................................................................................ 34
Table 3-11. Ozone Design Parameters. ....................................................................................................... 35
Table 3-12: BAC Design Parameters .......................................................................................................... 37
Table 3-13: UF Design Parameters ............................................................................................................. 38
Table 3-14: RO Design Parameters. ........................................................................................................... 42
Table 3-15: UV/AOP Design Parameters ................................................................................................... 43
Table 3-16: Footprint of FAT + O3/BAF AWTF ........................................................................................ 45
Table 3-17. Design Criteria for ESB-Cl2 + UF System .............................................................................. 47
Table 3-18: O₃/BAF + FAT + WTP for Treated Drinking Water Augmentation Footprint ....................... 47
Table 3-19. Footprint of FAT + O3/BAF AWTF at 25 mgd ....................................................................... 50
Table 4-1: Pipeline Velocity and Headloss – Option F ............................................................................... 55
Table 4-2: Pumping Requirements – Option F ........................................................................................... 55
Table 4-3: Pipeline Velocity and Headloss – Option G .............................................................................. 58
Table 4-4: Pumping Requirements – Option G .......................................................................................... 58
Table 4-5: Pipeline Velocity and Headloss – Option H .............................................................................. 62
Table 4-6: Pumping Requirements – Option H .......................................................................................... 62
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Table 4-7: Conveyance & Receptor Integration Costs by Option ............................................................. 65
Table 6-1: Anticipated RWQCB and DDW Permits for TM3 Reuse Options. .......................................... 76
Table 6-2: Basin Plan Groundwater Quality Objectives. ............................................................................ 78
Table 6-3: Basin Plan Surface Water Quality Objectives for San Dieguito Reservoir ............................... 80
Table 6-4: California Toxic Rule Standards for the Protection of Aquatic Habitat .................................... 82
Table 6-5: California Toxics Rule Standards for the Protection of Human Health .................................... 83
Table 6-6: Recommended Criteria for Chlorine for the Protection of Freshwater Aquatic Life ................ 86
Table 7-1: Cost Summary for Option F. ..................................................................................................... 92
Table 7-2: Cost Summary for Option G. ..................................................................................................... 93
Table 7-3: Cost Summary for Option H. ..................................................................................................... 93
Table 8-1: Summary of Key Considerations for EWA’s Potable Reuse Options. ...................................... 95
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1 Introduction
Feasibility Study Background
As required by Encina Wastewater Authority’s (EWA) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) will identify a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average annual daily flow of
approximately 31 million gallons per day (mgd).
The Study will focus on developing a portfolio of options for potential reuse projects; analyze a shortlist of
options (focus of this technical memorandum (TM)); develop an approach to phasing of the preferred water
reuse project; identify funding opportunities; develop a stakeholder involvement plan; and coordinate with
EWA member agencies and other potential stakeholders. Ultimately, the Study will serve to advance
EWA’s mission of resource recovery and contribute to sustaining and enhancing the region’s water
resources.
1.1.1 Preferred Options for Analysis
Through prior work on this Study, three preferred options have been identified for further analysis. Each
option includes improvements to the EWPCF and construction of a new Advanced Water Treatment
Facility (AWTF) to produce approximately 16 mgd of advanced treated water (or purified water) for potable
reuse. Additional details on each option are presented in this TM. The options are listed below, along with
the associated designation that will be used throughout this TM:
• Option F: 15.8 mgd of potable reuse through the following:
o Groundwater augmentation in the San Dieguito Valley groundwater basin (up to 2 mgd)
o Surface water augmentation in the San Dieguito Reservoir (up to 3.1 mgd)
o Treated drinking water augmentation introduced at the Carlsbad Desalination Plant
finished water pump station (ranging from 10.7 to 15.8 mgd)
• Option G: 16.0 mgd of potable reuse through the following:
o Groundwater augmentation in the San Dieguito Valley groundwater basin (up to 2 mgd)
o Surface water augmentation in the San Dieguito Reservoir (up to 3.1 mgd)
o Raw water augmentation in the Second Aqueduct, Pipeline No. 5 (ranging from 10.9 to 14
mgd)
• Option H: 16.0 mgd of potable reuse through the following:
o Groundwater augmentation in the San Marcos groundwater basin (up to 2 mgd)
o Raw water augmentation in the Second Aqueduct, Pipeline No. 5 (ranging from14 to 16
mgd)
Objectives
This TM includes conceptual analysis leading to a preliminary opinion of probable construction costs and
annual operational costs for each of the three preferred options at the projected 2040 flow levels (as
described in TM2). The analysis includes estimation of the unit cost of water produced (i.e., dollars per
acre-foot) to allow for comparison of existing and planned water resources expected to be available in the
region. The TM is organized as summarized below:
• Wastewater Treatment Plant Improvements: With a goal of providing improved source water
to a future AWTF, this section examines raw wastewater source control and improvements to the
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existing EWPCF secondary treatment process. Key outcomes include expected AWTF source
water quality and quantity.
• Purified Water Receptor Integration Concepts: For the surface water augmentation option, a
concept will be presented for diffusing the purified water into the reservoir and meeting the
anticipated regulatory requirements for dilution and retention time. For the groundwater
augmentation option, a concept will be presented for injection wells and extraction wells to meet
anticipated retention time requirements. For the treated drinking water augmentation option, a
concept will be presented for engineered storage and blending facilities to combine the purified
water with the desalination plant effluent.
• Advanced Water Treatment Concepts: To meet the requirements for potable reuse in California,
an AWTF will need to be constructed to deliver purified water to the specific receptor(s) in each
option. This section will present potential treatment trains tailored to each form of potable reuse
contemplated in the top options, as well as conceptual facility layouts for the AWTF options.
• Conveyance Concepts: Various pipeline alignment routes were considered for conveying purified
water from the AWTF to the proposed receptor(s). This section will present conceptual pipeline
alignments and pump station requirements for each option.
• Permitting Considerations and Brine Disposal: Based on the proposed modifications to the
EWPCF, the proposed AWTF, and the proposed forms of potable reuse, this section outlines the
associated considerations for permitting based on available information. Furthermore, permitting
requirements are outlined for disposal of RO concentrate (brine) generated at the proposed AWTF
via the Encina Ocean Outfall.
• Conceptual Cost Analysis: For each option, a feasibility-level Opinion of Probable Construction
Costs is provided. In turn, operational cost rates are added to each option to develop a cost of water
that can be compared across options, as well as to other water sources in the region.
• Conclusions: Based on the analysis in this TM and feedback from stakeholders, a recommendation
is provided to carry forward in the Study regarding project phasing analysis and funding
opportunity identification.
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2 Wastewater Treatment Plant Improvements
EWPCF Treatment Upgrades
No changes to the EWPCF treatment are expected to be required by current regulations to provide secondary
effluent to source non-potable reuse projects with EWA’s Member Agencies. However, current best
practice suggests that the source water for an AWTF should include biological nutrient removal (e.g.,
nitrification-denitrification [NDN]) and tertiary filtration. These modifications may also be required by
future potable reuse regulations. The following aspects of the EWPCF treatment upgrades and how they
pertain to potable reuse will be addressed in this section:
• Source control and industrial pretreatment
• Primary effluent flow equalization
• Conversion of secondary process to NDN
• Tertiary filters
• Management of sludge dewatering sidestreams
2.1.1 Source Control and Industrial Pretreatment
Effective source control and industrial pretreatment management programs are important for maintaining
consistent feed water quality for potable reuse. Source control and industrial pretreatment will help
minimize concentrations of chemicals of concern and illegal dumping events that can cause wastewater
treatment upsets.
EWA maintains a robust source control program in which they permit and monitor all industrial users in
the sewershed. The most recent data from their source control program is from 2015, at which time EWA
had 59 permitted industrial users, four of which were considered significant. As of the end of 2015, EWA
had no incidents of “upset, interference or pass-through” attributed to industrial users and industrial users
were contributing only 0.84% of the average daily influent flow (Encina Wastewater Authority 2017). All
regular sampling at both the ocean outfall and in receiving waters showed that EWA’s effluent quality met
or exceeded compliance standards.
In addition to the regulation of industrial users, EWA also implements a range of best management practices
(BMPs) aimed at reducing the level of pollutants entering the system. The BMP program involves working
with non-significant industrial users to identify specific pollution prevention strategies and follow-up
sampling and inspection to ensure the effectiveness of the program. Since its inception in 1999, the BMP
program has reduced the level of pollutants entering the treatment plant and has resulted in a decrease of
non-significant industrial user permits, including a decrease from 304 to 35 by the end of the second year
of the program (Encina Wastewater Authority 2017). Increased wastewater flows to EWA’s service area
are expected to result from increased residential development and should have little to no effect on the level
of industrial sources in the sewershed. If new industrial users enter the sewershed, EWA is well-equipped
to ensure that proper industrial source control and pretreatment is implemented to safeguard the influent
flows to the treatment plants.
2.1.2 Primary Effluent Flow Equalization
Primary effluent flow equalization stabilizes the organic and nitrogen load to the biological treatment
process, making the biological treatment, as well as each subsequent treatment step, easier to operate and
manage. The constant flow allows the processes to become more stable and reliable. It also allows for more
appropriate sizing of subsequent treatment processes, including membrane processes at the AWTF,
preventing over-design due to sizing for peak flows.
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Currently, EWPCF utilizes Aeration Basin No. 4 for primary flow equalization; however, this required
modifications to the basin and addition of manual controls. Converting the EWPCF to an NDN facility will
require additional aeration basin volume; thus, Basin No. 4 is likely to be needed for its original purpose in
the future.
A flow equalization simulation was performed to estimate the volume required to equalize an average daily
flow of 31 mgd assuming a typical diurnal flow pattern (Figure 2-1). Based on the simulation,
approximately 4.5 MG of equalization volume is required. A 20% safety factor was assumed resulting in a
total volume of 5.4 MG. Based on this analysis, two new 2.7 MG circular tanks are assumed to provide
primary flow equalization.
Figure 2-1: Projected EWPCF Diurnal Flow Curve and Flow Equalization Volume
2.1.3 Conversion of Secondary Treatment to NDN
Currently, EWPCF operates in a non-nitrifying mode which has the primary goals of reducing the
biochemical oxygen demand (BOD), total suspended solids (TSS) and turbidity of the secondary effluent
for ocean discharge. However, as mentioned, biological nutrient removal such as nitrification-
denitrification (NDN) is recommended for waters used as source waters for an AWTF. Running the EWPCF
as an NDN facility, specifically using the Modified Ludzack-Ettinger Process (MLE), will lead to more
consistent and better water quality with respect to BOD, TSS, turbidity, TOC and contaminants of emerging
concern (CECs). It will also reduce the downstream capital costs of filtration at the AWTF and reduce
fouling of the membranes. Typically, MLE requires greater aeration basin capacity than non-nitrifying
facilities. However, EWPCF currently uses only two of four aeration basins and can potentially
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accommodate MLE in the existing aeration basins so recent water quality data and biological modeling was
utilized to evaluate MLE at EWPCF.
The strength of the influent wastewater to the EWPCF has increased in recent years due to drought and
water conservation efforts. Table 2-1 presents and compares average influent and primary effluent strength
from 2011-2012 and 2016.
Table 2-1: Average Influent and Primary Effluent Strength for 2011 - 2012 and 2016
Parameter Units 2011-2012 2016 Percent
Change
Influent Flow mgd 23.2 21.0 -11%
Influent TSS mg/L 299 380 21%
Influent BOD mg/L 288 406 29%
Primary Effluent TSS mg/L 71 57 -25%
Primary Effluent BOD mg/L 159 203 22%
TSS Removal % 76 85 11%
BOD Removal % 44 50 12%
As shown in Table 2-1, the average influent TSS and BOD have increased by 21% and 29%, respectively,
since the sampling in 2011-2012. The primary effluent BOD also increased similarly (by 22%), but the
primary effluent TSS decreased. Though TSS removal was already quite high during the first sampling
(76% removal), it increased to 85% removal in 2016 leading to a decrease of 25% in primary effluent TSS.
Therefore, although influent TSS increased 21% from 2011-2012 to 2016, primary effluent TSS decreased
by 25% over this same interval. This could be explained by chemical enhancement of the primary
sedimentation, or perhaps by increases in chemical dosing or hydraulic residence time.
Overall, increases in influent TSS and BOD are dampened by primary sedimentation and do not affect
secondary processes as much as influent concentrations would suggest. Influent ammonia is not measured
but would follow the same trends as TSS and BOD, though ammonia would not be removed by primary
sedimentation. While increased ammonia concentrations do not impact conventional treatment, they are a
significant factor in NDN. Limited data is available on nitrogen in influent or primary effluent flows, so
additional sampling and profiling of the influent and primary effluent should be performed to further
develop the conversion to NDN.
Modeling of the EWPCF was conducted using GPS-X, a dynamic wastewater treatment simulator. The
model was calibrated using 2016 operational data as it is most representative of recent wastewater strength.
Table 2-2 presents the average historical conditions (January - December 2016) and the calibrated model
results. Once the model was calibrated to closely simulate the average conditions, it was used to simulate
NDN conditions at 2040 design flows, peak flows, and peak concentrations and sludge volume index (SVI)
assuming primary flow equalization and steady state conditions.
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Table 2-2: Modeling Results Summary
Parameters a Units
Existing
Average
Conditions
(2016)
Calibrated
Model
Results
NDN Modeling Results Typical Design Values
Current
Flow
Projected
2040
Flow
Peak
Flow c
Peak
Conc. &
SVI c, d
Conventional NDN
Flow mgd 21.0 21.0 21.0 31.0 40.3 31.0 --
Primary Clarifiers
Primary Clarifiers in Operation No. 6 6 6 9 10 9 --
Primary Overflow Rate gpd/sf 1094 1094 1094 1076 1259 1076 800 – 1000
Primary Detention Time hours 1.5 1.5 1.5 1.5 1.3 1.5 1.5 – 2.5
Primary Effluent TSS mg/L 57 57 57 57 57 70 --
Primary Effluent BOD mg/L 203 203 203 203 203 226 --
Primary Effluent TKN mg/L 46 46 46 46 46 50 --
Aeration Basins (Bioreactors)
Aeration Basins Online No. 2 2 3 3 4 4 --
Active Bioreactor Volume MG 4.68 4.68 7.02 7.02 9.36 9.36 --
Anaerobic/Anoxic Volume % 17 17 33 33 33 33 20 - 40
Bioreactor Detention Time hours 5.3 5.3 8.0 5.4 5.6 7.2 2.5 – 5.0 5.0 – 12
SRT days 1.88 1.88 8.0 8.0 8.0 8.0 <2.5 >8
Mixed Liquor Recycle Flow mgd 0 0 100 120 120 120 0 2Q – 4Q
RAS Flow g %Q 37 37 75 75 75 100 50 – 100
MLSS mg/L 1413 1415 2960 4313 4140 3940 1000 –
2500
2500 -
5000
Alpha factor e -- -- 0.6 0.4-0.6 0.4-0.6 0.4-0.6 0.4-0.6 0.4 – 0.6
SOTE f % -- 16 16 16 16 16 30
Dissolved Oxygen (Zones 3&6) mg/L 1.4/1.8 1.4/1.8 1.4/1.8 1.4/1.8 1.4/1.8 1.4/1.8 2
OUR (1st Aerobic Zone) mgO2/(L.h) NA 39 61 91 87 74 <100
Total Airflow scfm 10213 8465 29600 43300 55900 47000 -- Sept. 27, 2022Item #10 Page 119 of 279
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Table 2-2: Modeling Results Summary (Continued)
Secondary Clarifiers
Secondary Clarifiers in Service No. 5 5 5 7 8 8 --
SVI mL/g 150 150 150 150 150 180 --
WAS Rate mgd 0.74 0.74 0.39 0.38 0.51 0.66 --
WAS Concentration mg/L 4992 4764 6736 9903 9690 7700 --
2 Overflow Rate gpd/sf 485 485 476 505 575 440 400 – 700
2 Solids Loading Rate lb/(sf.d) 7.8 7.8 21.0 32.2 35.5 29.4 <35
2 BOD mg/L -- 5.7 5.0 6.0 6.0 5.0 --
2 TSS mg/L 7.56 9.00 9.00 12.00 12.00 10.00 --
2 Ammonia mg/L 33.7 34.0 0.2 0.2 0.2 0.2 >30 <1
2 Nitrite + Nitrate mg/L 0 0 15.0 15.0 14.3 14.3 0 <10
2 TKN mg/L -- 35.4 1.5 1.7 1.7 1.5 >30 <5
Footnotes:
a. SRT = solids retention time, RAS = return activated sludge, MLSS = mixed liquor suspended solids, OUR = oxygen uptake rate, WAS = waste activated sludge
b. Peak flow is assuming a peaking factor of 1.3
c. Peak conditions assume 4th aeration basin is in service and 8th clarifier is equipped and operational
d. Peak concentrations/SVI assume 90th percentile primary effluent BOD, TSS and TKN concentrations and SVI from 2016
e. Alpha factor based on low concentration MLSS and assumed to be lower for higher MLSS concentration; tapered through the aeration basin for NDN scenarios
f. SOTE calibrated to target approximate total aeration airflow assuming some of the existing airflow used for channel mixing
g. Higher RAS rate required for peak concentration/SVI condition to keep secondary clarifier blankets low
Parameters a Units
Existing
Average
Conditions
(2016)
Calibrated
Model
Results
NDN Modeling Results Typical Design Values
Current
Flow
Projected
2040
Flow
Peak
Flow c
Peak
Conc. &
SVI c, d
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The NDN model results for the 2040 projected flows show that NDN with the MLE process is possible
with the existing tanks/footprint at EWPCF; however, there is limited redundancy as three of four aeration
basins and seven of eight secondary clarifiers are in use at that condition. To ensure that current tankage
could handle peak storm events or other challenging circumstances (e.g., peak concentrations and reduced
sludge settleability), additional scenarios were modeled. The NDN model results at peak flows show that
existing tankage can treat up to 40.3 mgd, though all four aeration basins and all eight secondary clarifiers
would be in use. This is also the case for the peak concentration and SVI condition, for which the 90th
percentile primary effluent BOD, TSS, TKN and SVI values from 2016 were used as model inputs. There
is a significant increase in aeration demand and associated energy requirements for all NDN scenarios,
which is described in more detail in Section 2.3 below. The solids loading rate to the secondary clarifiers
appears to be the most limiting factor for all NDN conditions, and due to the lack of redundancy at 2040
peak conditions, two additional secondary clarifiers are recommended.
The biological modeling results for NDN at the projected 2040 flow are compared to the current operating
conditions of the City of San Diego’s North City Water Reclamation Plant (WRP) in Table 2-3. North City
WRP is designed to treat and reclaim up to 30 mgd of wastewater, though it currently receives only 15.4
mgd of influent flow. Recycled water produced at the North City WRP supplements the water supply of the
northern region of the City of San Diego, used primarily for industrial and agricultural purposes. The North
City WRP is an NDN facility that has been running successfully since 1996 and is similar in many ways to
the proposed EWPCF at 2040 design flows utilizing MLE.
Table 2-3: Aeration Basin Retrofit
Parameter Encina WPCF (2040) North City WRP a
Influent Flow 31.0 mgd 15.4 mgd
Aeration Basins
Duty/Total Number of Units 3/4 3/7
Sludge Retention Time (SRT) 8 days 10 days
Mixed Liquor Suspended Solids (MLSS) 4,313 mg/L 4,500 mg/L
Hydraulic Retention Time (HRT) 5.4 hours 5.1 hours
Secondary Clarifiers
Duty/Total Number of Units 7/8 8/14
Overflow Rate 505 gpd/sf 538 gpd/sf
Solids Loading Rate 32.2 lbs/sf-d 33.6 lbs/sf-d
Footnotes:
a) Based on operational data from July 1, 2016 through February 22, 2017.
Table 2-3 shows clear similarities between the estimated operational parameters for the EWPCF running
as an MLE facility and those employed at the North City WRP. EWPCF is closer to its full treatment
capacity than the North City WRP, but the similarity in operations suggests that the designs for the EWPCF
with MLE at 2040 flows are reasonable and yield results similar to the well-functioning North City WRP.
It is important to note that there are other treatment options available for achieving nutrient removal, such
as the use of a membrane bioreactor (MBR) in the secondary treatment process or using the secondary
effluent as source water for an MBR. Retrofitting the EWPCF with an MBR system would be a major
capital investment and would also carry high operating expenditures, including additional energy for air
scouring, chemicals for membrane cleans, and routine membrane replacements every 5-7 years. An MBR
treating a non-nitrified secondary effluent will also require a supplemental carbon source, such as methanol,
for denitrification. Based on the increased associated cost, MBR was not assessed in this Reuse Study.
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2.1.4 Tertiary Filters
Filtration is recommended to reduce the particulate matter in the secondary effluent prior to the AWTF.
Lower particulate levels will help improve the effectiveness of downstream membrane treatment processes
and reduce the maintenance requirements for the online meters. The filters will also provide a significant
buffer to any process upsets in the upstream wastewater treatment plant and redundancy of treatment
processes, which is ideal for potable reuse schemes.
Six granular media filters, each with a surface area of 440 ft2, are assumed to filter the 19 mgd of secondary
effluent to be treated by the AWTF. A waste wash water equalization basin is also required to equalize the
granular media filter and membrane filtration backwash flows. The filtrate from the tertiary filters will feed
the AWTF and does not need to adhere to Title 22 filtration requirements, so these filters can exceed 5
gpm/ft2. The predicted flow rate through all six filters is 5 gpm/ft2, increasing to 7.50 gpm/ft2 with two
filters offline.
2.1.5 Management of Sludge Dewatering Sidestreams
The dewatering of digested sludge results in liquid sidestreams that contain high concentrations of (1)
nutrients (ammonia and phosphorus), (2) polymers and organic components that are known precursors of
NDMA (a carcinogenic disinfection byproduct known to breach RO systems), and (3) recalcitrant organics
that behave as strong membrane foulants. Currently, EWPCF treats sludge dewatering sidestreams in the
plant with the rest of their water. It is critical to manage and dilute these sidestreams effectively to ensure
reliable nitrification, minimize NDMA formation, provide consistent treatment, and protect the downstream
membranes.
The best option for the management of sludge dewatering streams at EWPCF is to have separate treatment
for the sidestreams (e.g., a membrane bioreactor), and discharge the effluent into the ocean at the Encina
Ocean Outfall. This option will need to be assessed further to ensure that EWPCF can still meet their ocean-
discharge permits with the inclusion of these sidestreams. With this configuration, the treated effluent from
the sidestreams is not recycled through the treatment plant, which is ideal for both maintaining consistent
conditions for the biological processes and for improving effluent quality.
Alternatively, the sidestreams can be returned to primary flow equalization basins. By returning the sludge
dewatering sidestreams to primary flow equalization basins, these concentrated liquid streams are diluted
and slowly brought back into the biological treatment process when the BOD and ammonia load are lowest.
Preliminary Layout of Improvements
The modifications to the EWPCF and the proposed AWTF could be sited in the area south of the treatment
plant designated for expansion (except for the additional secondary clarifiers, which could fit in the current
EWPCF footprint) (Figure 2-2). Refer to Table 2-4 for the dimensions of the proposed facilities.
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Figure 2-2: Preliminary site layout for new facilities at EWPCF
Table 2-4: Dimensions of Proposed Facilities
Description Dimensions (ft)
Primary Flow EQ Tanks (2) 140 (dia.)
Tertiary Filters (6) 20 x 22 x 7 (L x W x D)
Waste Wash Water Basin 40 x 40 x 25 (L x W x D)
Tertiary Filter Perimeter 200 x 100 (L x W)
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Conceptual Costs for EWPCF Improvements
2.3.1 Capital Costs
Preliminary cost estimates were performed for the following EWPCF treatment improvements:
• Primary effluent flow equalization
• Conversion of the secondary process to MLE
• Tertiary filters
Estimates for sidestream treatment of the centrifuge centrate are not included in this preliminary cost
estimate associated with the EWPCF but should be further evaluated.
Primary effluent flow equalization assumes two concrete storage tanks, piping, a pump, flow meter, and
control valve. The costs of excavation and installation are included in the estimate as well.
Conversion of the secondary process to MLE will require the following modifications:
• Internal mixed liquor recycle (IMLR)
o Pumps
o Piping
• Anoxic Zones
o Baffling
o Mixing
o Scum and Foam Removal
• Aeration
o Larger blowers
o Larger air piping
o Additional fine bubble diffusers
• Clarification
o Two additional secondary clarifiers
The preliminary cost estimate (see Appendix A) assumes that NDN will take place in the existing aeration
basins with the retrofits listed above. Larger air piping, new blowers, and enhanced mixing make up the
bulk of the estimated additional capital associated with the aeration basin retrofit for MLE. It is assumed
that the existing blower building is adequate for accommodating the new blowers. If the existing aeration
piping is large enough for the anticipated airflow rates for nitrification, then the additional capital associated
with MLE could be considerably less than what is shown in Appendix A. Installation costs for this
equipment are listed separately.
Two additional circular secondary clarifiers are assumed with the same dimensions as the existing
secondary clarifiers. This cost estimate includes the cost of two new secondary clarifier structures and the
equipment for three clarifiers (i.e., to also equip the existing Secondary Clarifier No. 8 that is currently
unequipped). The costs of equipment, excavation and installation for the new clarifiers are included in the
estimate for the structures, while the equipment cost for the unequipped existing clarifier is listed as its own
line item. Installation for the unequipped secondary clarifier equipment is listed separately, in combination
with the installation of the aeration basin retrofit.
Six granular media filters are assumed with surface areas of 440 ft2, as well as a waste wash water
equalization tank with a capacity of 264,000 gal. The waste wash water tank was sized to hold three
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backwash volumes (estimated as 200 gal/sf filter surface area); this is a conservative sizing approach that
should also be sufficient to accommodate backwash water from membrane processes at the AWTF as well.
The cost estimates for the tertiary filters include excavation, piping and installation.
2.3.2 O&M Costs
The operations and maintenance (O&M) costs associated with NDN are also higher than non-nitrified
treatment. The cost increases over “status quo” EWPCF operating conditions are presented in Table 2-5
(based upon a rate of $0.15 per kWh), and are also included in Appendix A.
Table 2-5: Preliminary Estimate of Increase in O&M Cost with NDN
O&M Item Difference in Cost
Power
Aeration Blowers $2,013,000
IMLR Pumps $122,000
Anoxic Zone Mixers $47,000
Subtotal Power Costs $2,182,000
Equipment
Equipment Rehabilitation and Replacement $71,500
Estimated Annual O&M Increase $2,254,000
The O&M cost estimates assume that EWPCF is running at the design flow of 31 mgd. The difference in
O&M costs scale with flow should EWPCF not operate at the design condition. The principal driver for the
increase in O&M costs is the power demand associated with the increased aeration demand for nitrification.
It was assumed that no additional labor would be required over EWA’s baseline operations and that there
would be no increase in chemical costs as additional coagulant/polymer is not expected to be necessary.
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3 Advanced Water Treatment Concepts
Overview
In implementing potable reuse at the EWPCF, protection of public health requires adequate treatment to
remove pathogens and chemicals, a system of multiple barriers for reliability and redundancy, systematic
monitoring to ensure compliance, proper operation and maintenance, careful source control, and qualified
operator training. Combining treatment processes into a series of multiple barriers provides effective
pathogen and chemical pollutant reduction.
While the pathogen and chemical pollutant removal goals are the same for all types of potable reuse, the
actual combination of treatment processes can vary, depending on the end use. The major concerns of using
treated wastewater as a feed source for purification are the presence of pathogens and trace-level
constituents in secondary effluent (Rose et at., 2004, Olivieri et al., 2007, and Trussell et al., 2015).
Additional processes beyond secondary or tertiary treatment, defined as Advanced Water Treatment, are
used to produce advanced treated water (ATW) (Tchobanoglous et al., 2015). ATW must protect human
health, as well as surface water quality and groundwater quality, depending upon the use of the water. To
serve as a new water source, ATW must meet federal, state, and local regulations. A description of the
regulatory requirements and a review of water reuse projects in California and Nationally is provided in
this Study’s TM1: “Background of Potable Reuse in California".
From a risk reduction standpoint, minimization of both chronic and acute risk to consumers is the goal of
advanced treatment. From a public health perspective, potable water reuse depends on the combined
performance of various processes to remove pathogens and pollutants. These processes can only produce
water reliably if the overall treatment train is robust, redundant, and resilient (known as the “4 Rs”, Pecson
et al., 2015).
Each treatment process operates within a performance range, often normally or close to normally
distributed. This means that, for a small percentage of time, the performance of that process may be below
or above the expected value. From a treatment train perspective, should the low level of performance
(equating to lesser water quality) for one key process occur at the same time as the low level of performance
for another key process, there may be an increased risk to public health. This risk is minimized through
coupling reliability and redundancy. To make processes redundant, treatment processes are designed with
multiple barriers to provide effective pathogen and chemical pollutant reduction. While the pathogen
removal and chemical pollutant goal is the same for all types of potable reuse, the types and combinations
of treatment processes can vary based on the source water, end use, and other project-specific factors.
Treatment Technologies
Potable reuse treatment technologies have been documented in both demonstration and full-scale
applications through years of research and performance monitoring. This section summarizes accepted
treatment technologies that would be appropriate for producing ATW from EWPCF effluent.
3.2.1 Ozonation with Biologically Active Filtration
Ozonation (O3) with biologically active filtration (BAF) is a treatment combination used to break down
organic matter and trace pollutants into smaller molecules through chemical oxidation by ozone, so that the
biofilm developed in the biofilter can more readily biodegrade the oxidized organic matter. O3/BAF can be
installed ahead of microfiltration (MF) or ultrafiltration (UF) membranes, enhancing their operation. There
are three primary benefits of O3/BAF treatment:
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• reduction of TOC, both the bulk TOC and trace pollutants,
• reduction of pathogens, and
• removal of nutrients (e.g., ammonia removal through nitrification).
Results from two recent O₃/BAF demonstration projects for potable water reuse are summarized in this
section.
Pilot at Reno-Stead Water Reclamation Plant, Las Vegas, NV
An O₃/BAF demonstration project was completed as part of WRRF Project 11-02, and documented by
Trussell et al. (2015). The O3/BAF pilot plant used an O3 system from MiPro, advanced oxidation pilot
system from Xylem, and the BAF from Leopold Biofiltration. The O3/BAF was studied on a very high
quality secondary effluent, with and without microfiltration as pretreatment. Feed TOC was approximately
5 mg/L. TOC removal percentages were higher for MF filtered water (29-40 %, average 34 %) compared
to secondary effluent (26-33 %, average 30%). Substantial destruction and degradation of trace pollutants
(e.g., hormones and pharmaceuticals) was seen as part of this study.
Pilot at Santa Clara Valley Water District
An O₃/BAF demonstration project was completed at the Santa Clara Valley Water District (SCVWD)
(2015) using the same O3/BAF pilot plant as in Trussell et al. (2015). Two water qualities were used with
the O3/BAF setup (tertiary recycled water and secondary effluent) at O₃/TOC values of <1, and with BAF
empty bed contact times (EBCTs) of 20 to 30 minutes, based on Trussell et al. (2015). The goal of testing
the different operational scenarios was to maximize TOC reduction, destroy or reduce trace organic
constituents, and destroy pathogens, all while minimizing the construction cost of a future O3/BAF system.
Influent water quality plays an important role in O3 demand and O3 dosing costs. A stable influent water
quality lessens operational effort with a streamlined dosing system for both O3 and BAF. Overall, the TOC
removal for this study's O3/BAF pilot was approximately 20% when treating blended tertiary recycled
water, and 25 % when treating secondary effluent. The effluent TOC from the O3/BAF pilot ranged from 2
to 7 mg/L. Reduced performance on the tertiary recycled water was potentially due to the variability in feed
water quality, particularly due to the changing chlorine concentration and type (free or combined). Periodic
breakthrough of chlorine to the BAF could hinder the biological activity within the BAF. O₃/BAF showed
good reduction of ammonia through BAF (from ~1 mg/L to below detection [0.1 mg/L]), but nitrate levels,
as expected, remained high (~11 to 15 mg/L as nitrate-N). The BAF would need to be run in an entirely
different mode to provide denitrification.
Disinfection byproduct formation, particularly bromate, chlorate, and NDMA, is also a concern due to the
use of O₃, and thus was measured through the O3/BAF process at SCVWD (2015). O3 was shown to form
bromate, for which BAF was an effective removal technology. Higher O3/TOC ratios resulted in higher
bromate formation, as expected. In all tested cases, the O3/BAF finished water bromate concentration was
less than the MCL. Chlorate levels were low in the feed to the O3/BAF, with no measurable increase by
ozonation or decrease through BAF. The O3/BAF finished water chlorate concentration for all tests was
less than the notification level of 800 µg/L (NL). Consistent with other work, ozonation increases NDMA
formation, and BAF reduces NDMA concentrations. The key to meeting NDMA targets (such as 10 ng/L)
is to minimize NDMA levels upstream of ozonation (e.g., by separating sludge dewatering centrate
sidestream flows as described in Section 2.1.5 above).
Overall Performance for Pathogen Reduction: No log removal credit is obtained by BAF, though the
U.S. Environmental Protection Agency’s (USEPA) Long Term 2 Enhanced Surface Water Treatment Rule
could be used to obtain pathogen credit based upon filtered effluent turbidity values (USEPA, 2006).
However, log removal credit can be achieved by ozonation. Assuming a temperature of 15 ºC or higher,
Giardia is reduced by 3 log at a CT of 0.95 mg/min/L. At the same temperature, 4-log reduction of virus
occurs at a CT of 0.6 mg/min/L. A 5-log virus disinfection approval for O₃ disinfection is based upon a
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minimum CT of 1.0 mg/min/L. Trussell et al. (2015) documented similar virus kill. Both projects
consistently demonstrated 7+ log reduction of seeded MS2. Such log reduction of MS2 is conservatively
equivalent to 5-log reduction of poliovirus (Tchobanoglous et al., 2015).
3.2.2 Membrane Filtration - Microfiltration/ Ultrafiltration
Microfiltration (MF) and Ultrafiltration (UF) are both types of physical filtration processes. Membranes
used for MF applications have a pore size that ranges from 0.1 to 10 µm, while UF membrane pore sizes
are smaller, in the range of 0.001 to 0.1 µm. MF/UF is a robust technology that has proved to be effective
to remove Giardia oocysts and Cryptosporidium cysts, algae, and some bacterial species. However, MF is
not an effective barrier to viruses. On the other hand, UF have proven to be effective in removing viruses.
MF/UF processes have not been shown to remove a significant amount of chemical pollutants. A primary
function of the MF/UF system in a potable reuse treatment train is to provide adequate pretreatment for
sustainable operation of the RO process.
Recent DPR demonstration testing with Clean Water Services (CWS) (Oregon) indicates that a well-
functioning UF membrane (0.01 µm nominal pore size in this case) can attain 4.7-log reduction of seeded
virus (CWS, 2014) without chemical use (such as alum or polymer) ahead of the membrane. Equivalent or
greater reduction of protozoa can be assumed based upon this data, and is directly supported by NSF (2012).
Furthermore, MF or UF membrane integrity testing (MIT) confirms system performance and demonstrates
how MIT data can be used to track and ensure continued membrane performance (CWS, 2014).
Overall Performance for Pathogen Reduction: Both MF and UF membranes can be relied upon for 4+
log reduction of protozoa. System performance monitoring (to provide regulators confidence in the removal
credit) is accomplished by precise and accurate filtrate turbidity monitoring coupled with daily pressure
hold tests and MIT. Innovative methods to track MF or UF performance includes the use of bench-scale
particle counting and the use of adenosine triphosphate (ATP) to daily verify bacteria removal. ATP
provides a near real-time microbial monitoring tool that could allow better diagnosis and mitigation of
threats as compared to the more conventional MIT and turbidity monitoring.
3.2.3 Reverse Osmosis (RO)
The RO process in a potable reuse treatment train provides for removal of salt (measured as TDS and
electrical conductivity (EC)), organics (measured as total organic carbon (TOC)), and pathogens. RO
removes ~95 percent of incoming salt. Depending on the feed water quality, RO permeate can have a total
dissolved solids (TDS) concentration lower than 50 mg/L. Along with salt and TOC removal, RO removes
trace level pollutants as hormones, pharmaceuticals, and personal care products.
Studies have found virus removal by RO to be from 3 to >6-log (Reardon et al., 2005,
NRMMC/EPHC/NHMRC 2008, CWS 2014). Equal or greater removal is expected for protozoa based upon
size differences (protozoa being much larger than virus). However, the log removal value for RO pathogen
rejection is not governed by the ability of an intact membrane to reject pathogens; it is governed by the
ability to monitor process integrity (Reardon et al., 2005 and Schäfer et al., 2005). The monitoring tools
currently used, EC meters and TOC meters, can measure 99 percent or less removal of both parameters
through the RO process. Recently, the DDW granted 1.5-log reduction credit for all pathogens for RO
(WRD, 2013), based upon a requirement to continuously monitor TOC reduction across RO. The Orange
County Water District currently attains 2-log pathogen credit using online TOC meters.
Alternative technologies, such as online fluorescent dye monitoring, have been shown to have higher
accuracy in assessing membrane efficiency (Steinle-Darling et al., 2016, Kitis et al., 2003, Henderson et
al., 2009, Pype et al., 2013). The proprietary Trasar® fluorescent dye (Nalco) is stable over a range of
temperature and is not impacted by pH in the range of 4 to 10. At 600 g/mol, this compound is larger than
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the openings in the RO membrane, but smaller than the size of any target pathogen, making the Trasar
technology a potentially valuable tool for RO system performance monitoring.
The Trasar technology's efficiency to detect any flaw in a RO membrane was tested as part of the Ventura
Water Pure demonstration testing. The test included monitoring the removal of seeded virus MS2, EC, and
Trasar for different RO operational conditions, including "normal" operation, a cut O-ring condition, and
two chlorine oxidized RO membranes. The performance was tracked across both the first stage of RO and
for the entire RO. Results from this research demonstrate the ability to conservatively monitor 3 to >4-log
removal of virus using Trasar, compared to ~1.5-log removal of other monitoring surrogates (Steinle-
Darling et al., 2016).
Overall Performance for Pathogen Reduction: RO provides a robust removal for all pathogens and
substantial removal of trace level chemical pollutants. For the purposes of this Study, we are assuming 1.5-
log reduction for all pathogens, with an increase to 3.0-log reduction if the Trasar technology is used.
California DDW has stated that they are willing to approve the Trasar technology once a utility applies for
credit.
3.2.4 Advanced Oxidation Process (AOP)
In the event of pathogens passing through RO, the AOP process provides additional disinfection and
removal of trace organics. An ultraviolet irradiation (UV) dose of 235 mJ/cm2 will result in 6+ log
reductions of all target pathogens (USEPA 2006; Hijnen et al., 2006, Rochelle et al., 2005), including
Cryptosporidium, Giardia, and adenovirus. Potable water reuse UV AOP systems will commonly operate
at UV doses greater than 900 mJ/cm2; thus, higher reductions are theoretically possible, but DDW allows
only a maximum of 6-log reduction credits per any one treatment technology (CDPH, 2014).
Adding an oxidant before a high UV dose results in the generation of hydroxyl radicals during treatment,
providing an advanced oxidation process (AOP). The UV AOP provides destruction of a range of pollutants
that may pass through RO. Either Hydrogen peroxide (H2O2) or sodium hypochlorite (NaOCl) can be used
as an oxidant for this application. H2O2 is a more common oxidant than NaOCl for UV AOP applications.
Both the NaOCl and H2O2 UV AOPs are controlled by oxidant dose and UV dose (UV intensity, UV
transmittance, or power). However, the NaOCL UV process is also controlled by the influent pH to the UV
reactor and is sensitive to ammonia residual through the RO process, which has a high NaOCl demand,
thereby requiring a higher oxidant dose. Free chlorine concentration and pH should be closely monitored
to ensure the UV AOP design dose is met.
DDW requires the UV AOP to provide at least 0.5-log reduction of 1,4-dioxane, a conservative surrogate
for destruction of trace pollutants (CDPH, 2014). Additionally, NDMA, with a DDW notification level
(NL) of 10 ng/L, can pass through RO at low concentrations (typically 20 to 100 ng/L), requiring destruction
by UV photolysis (Sharpless and Linden, 2003). Therefore, it is common to set the UV dose at 900 mJ/cm2
or higher. This high UV dose photolyzes NDMA as well as many other smaller chemicals that may have
passed through the RO train. NDMA is particularly photolabile.
Overall Performance for Pathogen Reduction: UV/AOP reliably provides at least 6-log disinfection of
both protozoa and virus. The same system will reduce NDMA to <10 ng/L and destroy at least 0.5-log of
1,4-dioxane, thus also reducing other trace level pollutants. Online dose monitoring systems, using real
time inputs of UV, UV intensity, flow, and oxidant dosing, is recommended for continuous confidence in
UV AOP performance.
3.2.5 High-Flux Water Treatment Plant
To meet the anticipated regulations for direct potable reuse (following the Quirk Bill), in particular for
“treated drinking water augmentation”, a separate water treatment plant consisting of engineered storage
buffer (ESB), chlorination, and a high-flux UF system will be used to treat the purified water produced by
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the AWTF. The UF system will be able to achieve high fluxes (~120 gfd) due to the high quality of the
water.
For this case, the ESB has been designed to have a residence time of two (2) hours. This time will provide
response time to identify treatment and monitoring system failures and implement appropriate corrective
actions. Should the hold time of two hours pass without an “override” by the responsible operator (i.e.,
indicating successful resolution of any problems and return to required treatment quality), the “off-spec”
water would be diverted to waste, followed by continued diversion until all issues are remedied.
Proposed Treatment Trains
The proposed treatment trains for this Study’s Options combine the available technologies for advanced
water treatment of pathogens and pollutants in accordance with current California state regulations for
potable water reuse through groundwater injection and surface water augmentation. The proposed treatment
trains (Figure 3-1 below) include RO for reduction of salts as well as the removal of pollutants and
pathogens. The brine from the RO process will be disposed via the Encina Ocean Outfall. Backwash water
for the MF/UF will be directed to the Carlsbad Water Reclamation Facility (CWRF) to augment non-potable
reuse supplies.
a. Full Advanced Treatment (FAT) AWTF: this widely accepted treatment train includes
membrane filtration (MF/UF), reverse osmosis (RO), and an ultraviolet light/advanced oxidation
step (UV/NaOCl AOP). NaOCl as an oxidant for AOP presents benefits such as increased
disinfection due to the presence of free chlorine, lower chemical cost, and operator familiarity. An
additional benefit of the UV/NaOCl AOP is a more efficient generation of hydroxyl radicals at a
low pH (<6), because RO permeate is typically in this pH range and can be readily controlled within
this range. This treatment train is tailored to groundwater and surface water (reservoir)
augmentation projects.
b. FAT with O3/BAF AWTF: this treatment train adds ozonation (O₃) with biologically active
filtration (BAF) as pretreatment before MF/UF. These additional treatment steps provide further
pathogen removal and enhanced water quality, improving the performance of downstream
technologies. This treatment train is anticipated to be appropriate for raw water augmentation
projects, based on currently available information (DDW regulations are pending).
c. FAT with O₃/BAF AWTF plus WTP: in addition to the FAT with O3/BAF advanced treatment
train, an additional barrier and treatment would be provided by a tailored Water Treatment Plant
(WTP) consisting of an Engineered Storage Buffer (ESB) with chlorination (Cl2) and a high-flux
UF system. This treatment train is anticipated to be appropriate for integration with the potable
water system, based on currently available information (DDW regulations are pending).
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Figure 3-1: Advanced Treatment Train Options.
Raw Water
Pipeline or WTP
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Unit Process Monitoring
The performance of each treatment process is measured by log reduction of pathogens and removal of
chemical compounds. Because a system of multiple barriers is added up to meet the total log reduction
criteria established by regulations, it is important to understand the log reductions that occur across each
process. The log reduction credit (LRC) of each process is subject to the ability to accurately monitor system
performance, either online or periodically. In California, the potable reuse goals (from source to drinking
water) to meet regulatory criteria are defined in Table 3-1, better known as the 12/10/10 rule.
Table 3-1: Potable Reuse Pathogen Reduction Requirements (from source water to potable water).
Applicable Potable Reuse Form Virus Giardia Crypto.
Groundwater Augmentation
Surface Water Augmentation (standard: Dilution 100:1) 12 10 10
Surface Water Augmentation (reduced dilution: 100:1 Dilution 10:1) 13 11 11
Raw Water and Treated Drinking Water Augmentation* 14+ 12+ 12+
Footnotes:
* It is expected that the State will increase several LRC for raw water augmentation and treated drinking water augmentation
projects. This increase does not imply an increase in health protection, but rather risk minimization to mitigate the potential of
process failure without an environmental buffer.
3.4.1 Expected Performance of Proposed Treatment Trains
The anticipated total performance of a proposed treatment train will depend upon the coupled treatment
processes, which in turn depends upon the planned type of potable water reuse. Tables 3-2 through 3-5
summarize the treatment performance for the proposed treatment trains described in Section 3.3 above.
Table 3-2: Expected Performance of Treatment Train “a” for Groundwater Augmentation.
Parameter Primary/Secondary
Treatment UF1 RO2 UV/AOP3 Underground
Travel Time4
Total
Credits Goal
Virus (log) 1.9 0 1.5 6 2.6 12.0 12
Giardia cysts
(log) 0.8 4 1.5 6 0 12.3 10
Crypto. oocysts
(log) 1.2 4 1.5 6 0 12.7 10
1,4-dioxane X 0.5-log
by AOP
NDMA X X <10
ng/L
Turbidity X <0.2
NTU
TOC X <0.5
mg/L
Drinking Water
MCLs X X X Varies
Footnotes:
1. Although UF can achieve greater than 2 LRC for virus, no regulatory credit is expected to be granted.
2. Online TOC monitoring can conservatively obtain 1.5 LRC.
3. Assumes NaOCl as oxidant can achieve comparable results to H2O2 as oxidant for 6 LRC.
4. DDW regulations set a minimum time of 2 months. Virus removal can be correlated with time at 1-log removal per
month. For this example, 2.6 months is needed to obtain the full credit. Alternatively, Trasar® technology could be
used for the RO process to demonstrate 3 LRC instead of 1.5 LRC with online TOC monitoring.
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Table 3-3: Expected Performance of Treatment Train “a” for Surface Water Augmentation.
Parameter Primary/Secondary
Treatment UF RO1 UV/AOP2 WTP Total
Credits Goal3
Virus (log) 1.9 0 1.5 6 4 13.4 13
Giardia cysts (log) 0.8 4 1.5 6 3 15.3 11
Crypto. oocysts (log) 1.2 4 1.5 6 3 15.7 11
1,4-dioxane X X 0.5-log
by AOP
NDMA X X <10
ng/L
Turbidity X X <0.2
NTU
TOC X X <0.5
mg/L
Drinking Water MCLs X X X X Varies
Footnotes:
1. Online TOC monitoring can conservatively obtain 1.5 LRC.
2. Assumes NaOCl as oxidant can achieve comparable results to H2O2 as oxidant for 6 LRC.
3. Assumes reduced dilution credit requirements.
Table 3-4: Expected Performance of Treatment Train “b” for Raw Water Augmentation.
Parameter
Primary/
Secondary
Treatment
O₃ BAF UF RO1 UV/AOP2 WTP Total
Credits Goal
Virus (log) 1.9 5 0 0 3.0 6 4 19.9 14+
Giardia
cysts (log) 0.8 3 0 4 3.0 6 3 19.8 12+
Crypto.
oocysts
(log)
1.2 0 0 4 3.0 6 3 17.2 12+
1,4-
dioxane X X 0.5-log by
AOP
NDMA X X X <10 ng/L
Turbidity X X X <0.2 NTU
TOC X X X X <0.5 mg/L
Drinking
Water
MCLs
X X X X X X Varies
Footnotes:
1. Use of Trasar® technology for 3 LRC.
2. Assumes NaOCl as oxidant can achieve comparable results to H2O2 as oxidant for 6 LRC.
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Table 3-5: Expected Performance of Treatment Train “c” for Treated Drinking Water
Augmentation.
Parameter
Primary/
Secondary
Treatment
O₃ BAF UF RO1 UV/AOP2 ESB/
Cl2 UF Total
Credits Goal
Virus (log) 1.9 5 0 0 3.0 6 6 1 22.9 14+
Giardia
cysts (log) 0.8 3 0 4 3.0 6 3 4 23.8 12+
Crypto.
oocysts
(log)
1.2 0 0 4 3.0 6 0 4 18.2 12+
1,4-
dioxane X X 0.5-log by
AOP
NDMA X X X <10 ng/L
Turbidity X X X <0.2 NTU
TOC X X X X <0.5 mg/L
Drinking
Water
MCLs
X X X X X
X Varies
Footnotes:
1. Use of Trasar® technology for 3 LRC.
2. Assumes NaOCl as oxidant can achieve comparable results to H2O2 as oxidant for 6 LRC.
3.4.2 Critical Control Points
Operation, maintenance, and monitoring of each the processes used in advanced water treatment is of
critical importance to ensure that the finished water is protective of public health. End-of-pipe compliance
monitoring and performance-based monitoring are used to ensure that the AWTF continuously and reliably
meets the regularity criteria. The benefit of a performance-based monitoring approach is to identify and
implement Critical Control Points (CCPs) where hazards to human health risks can be reduced, prevented,
or eliminated (Mosher et al., 2016).
NWRI defines a CCP as "a point in advanced water treatment where control can be applied to an individual
unit process to reduce, prevent, or eliminate process failure and where monitoring is conducted to confirm
that the control point is functioning correctly. The goal is to reduce the risk from pathogen and chemical
constituents." (Tchobanoglous, 2015).
The CCP is intended to effectively monitor process performance, and hence relies upon the consistency of
the monitoring system. Monitoring system failures can be gradual (sensor drift), slight (sensor bias), result
in a loss in sensitivity, false positives, and false negatives, and even result in outright failure. Table 3-5
shows examples of CCPs for an AWTF and the corresponding monitoring requirements (Tchobanoglous,
et al., 2015).
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Table 3-6: CCPs for an AWTF.
CCP Monitoring Tool
O3 / BAF Online ozone dose, empty bed contact time (EBCT); control dose based on the
ozone-to-TOC ratio and ozone CT.
MF / UF Daily pressure decay testing (PDT). Values in accordance with membrane supplier
recommendations and validation to demonstrate membrane integrity
RO
Online EC or online TOC or online fluorescence. Log reduction of EC or TOC or
fluorescence across the RO process to demonstrate a minimum level of pathogen
removal.
UV-AOP Intensity sensors. Following USEPA 2006 or other methods, online intensity
monitoring demonstrates disinfection dose delivery.
Footnote: Adapted from Tchobanoglous et al., 2015 and Mosher et al., 2016
Facility Planning and Conceptual Layouts
The purification systems described here are intended to receive effluent from the EWPCF’s proposed
tertiary filters. It is assumed that the existing Secondary Effluent Equalization Pumps (SEEPs) capacity
could be used to pump EWPCF effluent to the potential future AWT site, and thus there would be no added
cost or engineering required for this effort. The UF and RO recoveries are estimated at 93% and 85%1,
respectively. The UV/AOP process uses sodium hypochlorite (NaOCl) as oxidant. The process is designed
for an available EWPCF effluent flow of 20.5 mgd.
The conceptual facility layouts are intended to accommodate the additional staff required to operate the
facility (including administration offices, maintenance shops, and vehicle access and parking), as well as
accommodating public tour groups (including additional parking area and a large meeting room).
Furthermore, the conceptual layouts have been configured to avoid conflicts with other planned uses for
the South Parcel, including future Interstate 5 expansion, widening and re-alignment of Avenida Encinas,
and additional secondary flow equalization facilities.
3.5.1 AWTF for Groundwater and Surface Water Augmentation
The preliminary design parameters used for the conceptual design of the AWTF for potable reuse via
groundwater augmentation and surface water augmentation are shown in Table 3-7 through Table 3-9.
Table 3-7: UF System Design Parameters
System Component Design Value Unit
UF Feed Tank
Number of tanks 1
Volume for operational equalization, minimum 130,000 gal
Total residence time, minimum 11.5 min
Total water volume 163,000 gal
UF Feed Pump
Pump type Vertical Turbine
Number of duty pumps 4
1 These estimated recoveries can be refined in the future with additional analysis of EWPCF water quality and
specific treatment equipment.
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System Component Design Value Unit
Number of standby pumps 1
Capacity per pump 5.1 mgd
Drive type VFD
Automatic Strainer
Manufacturer/model Amiad Omega, SP Kinney: AF, Eaton 2596, Fluid
Engineering Model 723, or equal
Type Auto-backwash strainer
Design flow 20.5 mgd
Clean head loss, minimum <1 psi
Duty units 4
Standby units 1
Excess capacity required 25 %
Capacity per strainer 6.41 mgd
Screen pore size, minimum 3 m
Strainer recovery 99.93 %
Automatic strainer backwash residuals estimates
Backwash average waste flow 3,000 - 33,000 gpd
Backwash duration per unit, per cycle 25 - 120 sec
Backwash volume per unity, per backwash cycle 148 - 800 gal
Backwash flow rate per unit, instantaneous 180 - 740 gpm
UF
Manufacturer Toray
Model Number HFU-2020N
Membrane nominal pore size 0.01 µm
Membrane area 775 ft2
System rated capacity (filtrate flow) 19.1 mgd
Feed flow 20.5 mgd
UF Recovery (assumed) 93 %
Number of total racks 10
Number of membrane modules per rack, installed 86
Number of membrane modules per rack, total
available 96
Design flux, maximum instantaneous (N-2) 38.4 gfd
Backwash water supply UF filtrate
Backwash type Reverse flow with air scour
Backwash interval 24 min
Design NaOCl Maintenance Cleaning (MC)
frequency 2x/week
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System Component Design Value Unit
Design Citric Acid (C6H8O7) (MC) frequency 1/month
Design Cleaning In Place (CIP) frequency 1/month
Direct Integrity Testing (DIT) method Daily PDTs
Indirect integrity testing method
Continuous filtrate turbidity
monitoring
UF Backwash Pumps
Pump type Horizontal Centrifugal
Number of duty pumps 1
Number of standby pumps 1
Flow rate, each pump 2,800 gpm
Total Dynamic Head (TDH) 100 ft
UF Backwash Flow Rates
Cycle length between backwashes (duration of
permeate production) 24 min
Total backwash cycle duration 3.17 min
Backwash flux 54.8 gfd
Backwash flow rate per module 29.5 gpm
Modules per rack, total 96
Backwash flow rate, per rack (maximum
instantaneous) 2,830 gpm
UF Backwash Residuals Estimates
Backwash cycles per day (system) 424
Backwash waste volume per cycle per rack 8,884 gal
Daily average residuals 1.4 mgd
UF Air Scour Blowers
Blower Type
Positive-displacement lobe,
or hybrid rotary lobe
Number of sets 2
Number of blowers on duty 1
Number of blowers on standby 1
Blower capacity, each 665 cfm
Blower pressure 15 psi
Blower motor power, each 60 hp
UF CIP/MC Cleaning procedures
Typical duration, each rack, each clean 27-90 min
Design Frequency
NaOCl: 2x/week
C6H8O7: 1/month
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System Component Design Value Unit
Make-up water UF filtrate
Solution temperature, typical 100 ˚F
CIP/MC System
CIP/MC systems, total 2
CIP fill pumps on duty 1
CIP fill pumps on standby 1
CIP fill pump flow rate, each 500 gpm
CIP fill pump TDH
38 ft
CIP fill pump motor power, each 7.5 hp
MC fill pumps on duty 1
MC fill pumps on standby 1
MC fill pump flow rate, each 500 gpm
MC fill pump TDH 20 ft
MC fill pump motor power, each 5 hp
CIP tanks per system 2
CIP tank volume, each 6,000 gal
CIP pumps on duty 1
CIP pumps on standby 1
CIP pump flow rate, each 1,235 gpm
CIP pump TDH 97 ft
CIP pump motor power, each 50 hp
Neutralization System
Neutralization systems 2
Neutralization tanks per system 1
Neutralization tank volume, each 15,000 gal
Pumps on duty 1
Pumps on stand-by 1
Neutralization/drain pump TDH 43 ft
Neutralization/drain pump flow rate, each pump 500 gpm
Neutralization/drain pump motor power, each
pump 10 hp
Time to drain neutralization tank 30 min
UF CIP/MC Residuals Estimates
Average CIP waste flow 6,300 gpd
CIP duration, total 4 to 6 hr
CIP chemical solutions, per CIP
1. Chlorine
2. C6H8O7
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System Component Design Value Unit
CIP waste volume per CIP chemical solution 11,100 gal
CIP waste volume per CIP total 22,200 gal
Average MC waste flow 35,500 gpd
MC duration, total Up to 90 min
MC waste volume per MC, total 11,100 gal
CIP/MC waste flow from neutralization tanks to
drain, total 1,000 gpm
Average MC waste flow 35,500 gpd
UF compressed air system (for pneumatic valves and the integrity testing system)
Compressors duty 1
Compressors standby 1
Compressor type Rotary screw compressor
Compressor size, each 15 kW
Air receivers duty 1
Air receivers standby 1
Air receiver pressure rating 200 psi
Air receiver operating pressure 100-150 psi
Table 3-8: RO System Design Parameters
System Component Design Value Unit
RO Feed Tank
Number of tanks 1
Available volume for operational equalization 8,000 gal
Residence time, minimum 15 min
Volume required for minimum residence time 198,600 gal
Cartridge Filters
On duty 3
On standby 1
Flow per vessel 4,413 gpm
Vessel configuration Horizontal
Vessel pressure rating 150 psi
Cartridges per vessel 32
Cartridge rating 5 um
Cartridge material Polypropylene
Cartridge diameter 6 in
Cartridge length 40 in
RO System Flow Stream pH and Chemical Doses
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System Component Design Value Unit
pH Ranges
UF filtrate 6.7 - 7.7
RO feed (dosed) 6.2 - 6.7
RO permeate (typical) 4.8 - 5.7
RO concentrate 7.0 - 7.5
Chemical Dosing
Antiscalant 1.0 - 5.0 mg/L
H2SO4 10 - 100 mg/L
RO Trains
RO Feed 19.1 mgd
RO Permeate 16.2 mgd
Duty 7
Standby 1
RO feed pump flow 1890 gpm
RO feed pressure 100-225 psi
RO recovery (assumed) 85%
RO Stages 3
1st Stage Pressure Vessels 46 Pressure Vessels
Elements Per Vessel 6
2nd Stage Pressure Vessels 23 Pressure Vessels
Elements Per Vessel 6
3rd Stage Pressure Vessels 11 Pressure Vessels
Elements Per Vessel 6
Elements per train 480
Total Elements 3,360
Membrane Hydranautics ESPA2-LD
RO CIP System
CIP tanks on duty 1
CIP tanks on standby 1
CIP tank volume 7,000 gal
CIP tank diameter 12 ft
CIP tank total height 10 ft
Heaters per CIP tank 2
CIP heat power 200 kW
Target CIP solution temperature 45 °C
CIP solution heating time 2 hr
Target CIP solution pH 2 or 11.5
Recirculation rate: Stage 1 1,060 gpm (two halves)
Recirculation rate: Stage 2 1,060 gpm
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System Component Design Value Unit
CIP pumps on duty 1
CIP pumps on standby 0
CIP pump flow rate 1,060 gpm
CIP pump pressure 60 psi
Table 3-9: UV/AOP Design Parameters
System Component Design Value Unit
UV/AOP TrojanUV
Reactors on duty 3
Reactors on standby 1
Oxidant type HOCl
Flow, design 15.7 mgd
Flow capacity per duty train 5.2 mgd
Minimum electrical energy delivered (EED) 0.2 kWh/kgal
Design EED 0.2 kWh/kgal
Minimum UV dose 920 mJ/cm2
Maximum operating pressure 30 psi
Head loss at full flow 4 in
Minimum UVT 96 %
Oxidant Dosing
Oxidant Dosing Free chlorine (HOCl)
Oxidant dose, design 2 mg/L as Cl2
Oxidant dosing system, minimum 2 mg/L as Cl2
Oxidant dosing system, maximum 5 mg/L as Cl2
Chemical Addition NaOCl
Strength of solution 12.5 %
Product Water Tank HRT Volume (gal)
HRT at Full
Capacity (min)
CO2 injection box 40,000 3.6
Lime injection box: 2 boxes on line 22,000 2.0
Lime injection ox: 1 box off line 11,000 1.0
Pump wet well 35,000 3.1
CO2 Storage
Storage time: worst-case conditions 4 days
Tanks 2
CO2 transfer efficiency 95 %
CO2 dose: max 90 mg/L
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System Component Design Value Unit
CO2 feed rate: max (actual) 26,886 lb/d
Net capacity: max conditions, per tank 24 metric ton
Lime Silo
Diameter 12 ft
Height 30 ft
Storage capacity per tank 3,393 ft3
Design total storage capacity 6,786 ft3
FAT AWTF Footprint
The total footprint of the proposed AWTF is approximately 226,300 ft2 (5.2 acres). The total area is based
on the footprint provided by the equipment manufacturers and includes the area for the administration
building, electrical room, electrical building, roadway, and parking (Table 3-10). Figure 3-2 shows the
tentative location of the AWTF on EWA’s South Parcel.
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Table 3-10: FAT AWTF Footprint.
Figure 3-2: Representative Layout of the FAT AWTF on EWA’s South Parcel.
Process Footprint (ft2)2
UF Trains 16,000
RO Trains 18,000
CIP System 2,000
UV System 3,600
Electrical Rooms 5,000
Electrical Building 9,000
Chemical Feed System /Storage 11,300
CO2 Dosing System 2,000
Lime Dosing System 3,000
Product Water Tank 14,700
Pump Station 8,100
Administration Building1 14,000
Parking 40,600
Roadway 79,000
Total Footprint 226,300
Footnotes:
1. The administration building area includes offices, conference rooms, exhibit space, maintenance shops/
storage, control room, water quality laboratory, lunchroom, restrooms, showers, and miscellaneous storage
space.
2. Rounded to the nearest 100.
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3.5.2 AWTF for Raw Water Augmentation
The assumed preliminary design parameters used for the conceptual design of the AWTF including O₃/BAF
+ FAT are shown in Table 3-11. The O₃/BAF provides favorable conditions to design the UF with a higher
flux. For the UV/AOP process, the design uses sodium hypochlorite (NaOCl).
Table 3-11. Ozone Design Parameters.
System Component Design Value Unit
Liquid Oxygen (LOX) System
LOX Tanks 2
Tank volume (each) 10,000 gal
Vaporizers 3
Vaporizer capacity (each) 27,500 scfh
Number of Gaseous Oxygen (GOX) Particulate Filters 1
Number of Stand-by GOX Particulate Filters 1
Minimum GOX Filter Capacity 400 scfm
Ozone Generators
Ozone dose, design 14 mg/L
Ozone dose, minimum 5 mg/L
Flow, design 20.5 mgd
Number of duty ozone generators 2
Number of standby ozone generators 1
Minimum generator capacity (each) 1,200 lb/d
O₃ Gas Concentration range at design dose 7 - 12 %
Oxygen supply LOX System
Power Requirements 4.5 kWh/lb O₃
Maximum feed gas dew point -65 °C
Cooling Water System
Open-Loop cooling water pumps, duty 2
Open-Loop cooling water pumps, Standby 1
Closed-Loop Cooling Water Pumps, Duty 2
Closed-Loop Cooling Water Pumps, Standby 1
Number of duty heat exchangers 1
Number of standby heat exchangers 1
Source of open-loop cooling water UF filtrate
Open-loop flow per pump 250 gpm
Motor horsepower per open-loop pump 20 hp
Source of closed-loop makeup water Stabilized RO
product water
Max temperature of open-loop supply 86 F
Max temperature rise across open loop 7.5 F
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System Component Design Value Unit
Minimum heat transfer efficiency 90 %
Pressure differential between loops 5 psi
Ozone Side Stream Injection System
Injection Type Side stream
Number of duty skids 4
Number of standby skids 2
Number of injectors per skid 1
Number of pumps per skid 1
Pump capacity 1,200 gpm
Pump Pressure 80 psi
Number of injection nozzles per flash reactor 6
Minimum 3 transfer efficiency 90%
Ozone Contactors
Type of ozone contactor Serpentine, vertically stacked
Number of ozone contactors 2
Flow, design 20.5 mgd
Flow, design (per contactor) 10.25 mgd
Design HRT 9.65 min
T12/HRT 0.79
Effective HRT (T10) 7.6 min
Design CT (@ 20°C) 3.8 mg-min/L
Sodium Bisulfite Quenching System
Injection Point Ozone Contactors
Design HRT for quenching ozone residual in ozone
contactors 1.2 min
Concentration 25 % by weight
Maximum dose, design 3 mg/L
Ozone Off-Gas Destruct System
Number of duty destruct units 2
Number of standby destruct units 1
Type of destruct units Thermal Catalytic
Maximum ozone concentration in destruct 0.1 ppm
Minimum pressure at basin headspace -4 inches
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Table 3-12: BAC Design Parameters
System Component Design Value Unit
Number of duty filters 5
Number of standby filters 1
Media depth 10 ft
Feed flow, design 20.5 mgd
Filtrate flow, design 20.2 mgd
Filtrate flow, design (per filter) 4.0 mgd
Water Recovery 98.5%
Filter surface area (per filter) 750 ft2
Backwash frequency per filter 2 per week
Backwash water supply source UF feed tank
Backwash flux 10 - 25 gpm/ft2
Backwash flow rate 12.4 - 24.8 mgd
Backwash time 10 min
Backwash volume per filter 173,000 gal
EBCT 14 min
Air scour rate 4 cfm/ft2
Air scour flow rate 3,000 scfm
Air scour duration 6 min
Hydraulic pause duration 5 min
Filter Media Bed Design Criteria
Media Product 8 x 16 mesh granulated activated carbon
Media Type Virgin bituminous coal-based GAC
Effective size 1.3 to 1.5 mm
Uniformity coefficient, maximum 1.4
Media bed length-to-diameter ratio 2,177
Predicted clean bed head loss 1.8 to 2.1 ft
BAC System Backwash Equipment
Number of backwash pumps, duty 2
Number of backwash pumps, standby 1
Backwash pump flow, each 9,375 gpm
Backwash pump pressure 37 psi
Backwash pump power 125 hp
Backwash pump type Horizontal split case
Number of air scour blowers, duty 1
Number of air scour blowers, standby 1
Air scour blower flow, each 3,000 scfm
Air scour blower backpressure 9.1 psi
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System Component Design Value Unit
Air scour blower power 200 hp
Air scour blower type Positive displacement
Table 3-13: UF Design Parameters
System Component Design Value Unit
UF Feed Tank
Number of tanks 1 Available volume for operational
equalization, minimum 130,000 gal
Total residence time, minimum 11.5 min
Total water volume (including
submergence) 163,000 gal
UF Feed Pump
Pump type Vertical Turbine
Number of duty pumps 4
Number of standby pumps 1
Capacity per pump 5.0 mgd
Drive type VFD
Automatic Strainer
Manufacturer/model
Amiad Omega, SP Kinney: AF, Eaton 2596, Fluid Engineering
Model 723, or equal
Type Auto-backwash strainer
Design flow 20.2 mgd
Clean head loss, minimum <1 psi
Duty units 4
Standby units 1
Excess capacity required 25 %
Capacity per strainer 6.31 mgd
Screen pore size, minimum 3 m
Strainer recovery 99.93 %
Automatic strainer backwash residuals estimates
Backwash average waste flow 3,000 - 33,000 gpd
Backwash duration per unit, per cycle 25-120 sec
Backwash volume per unity, per backwash
cycle 148-800 gal
Backwash flow rate per unit, instantaneous 180 - 740 gpm
UF
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System Component Design Value Unit
Manufacturer Toray
Model Number HFU-2020N
Membrane nominal pore size 0.01 m
Membrane area 775 ft2
System rated capacity (filtrate flow) 18.8 mgd
Feed flow 20.2 mgd
Assumed Recovery 93 %
Number of total racks 8 Number of membrane modules per rack,
installed 86 Number of membrane modules per rack,
total available 96
Design flux, instantaneous (N-2) 50.5 gfd
Backwash water supply UF filtrate
Backwash type Reverse flow with air scour
Backwash interval 24 min
Design NaOCl EFM frequency 2x/week
Design C6H8O7 EFM frequency 1/month
Design CIP frequency 1/month
DIT method Daily PDTs
Indirect integrity testing method Continuous filtrate turbidity monitoring
UF Backwash Pumps
Pump type Horizontal Centrifugal
Number of duty pumps 1
Number of standby pumps 1
Flow rate, each pump 2,800 gpm
TDH 100 ft
UF Backwash Flow Rates Toray Cycle length between backwashes
(duration of permeate production) 24 min
Total backwash cycle duration 3.2 min
Backwash flux 54.8 gfd
Backwash flow rate per module 29.5 gpm
Modules per rack, total 95 Backwash flow rate, per rack (maximum
instantaneous) 2,800 gpm
UF Backwash Residuals Estimates
Backwash cycles per day 424
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System Component Design Value Unit
Backwash waste volume per cycle per
rack 8,884 gal
Average backwash waste flow 1.4 mgd
UF Air Scour Blowers
Blower Type Positive-displacement lobe, or hybrid rotary lobe
Number of sets 2
Number of blowers on duty 1
Number of blowers on standby 1
Blower capacity, each 665 cfm
Blower pressure 15 psi
Blower motor power, each 60 hp
UF CIP/EFM Cleaning procedures MC
Typical duration, each rack, each clean 27-90 min
Design Frequency NaOCl: 2x/week, C6H8O7: 1/month
Make-up water UF filtrate
Solution temperature, typical 100°F
CIP/EFM System
CIP/EFM systems, total 2
CIP fill pumps on duty 1
CIP fill pumps on standby 1
CIP fill pump flow rate, each 500 gpm
CIP fill pump TDH 38 ft
CIP fill pump motor power, each 7.5 hp
EFM fill pumps on duty 1
EFM fill pumps on standby 1
EFM fill pump flow rate, each 500 gpm
EFM fill pump TDH 20 ft
EFM fill pump motor power, each 5 hp
CIP tanks per system 2
CIP tank volume, each 6,000 gal
CIP pumps on duty 1
CIP pumps on standby 1
CIP pump flow rate, each 1,235 gpm
CIP pump TDH 97 ft
CIP pump motor power, each 50 hp
Neutralization System
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System Component Design Value Unit
Neutralization systems 2
Neutralization tanks per system 1
Neutralization tank volume, each 15,000 gal
Pumps on duty 1
Pumps on standby 1
Neutralization/drain pump TDH 43 ft
Neutralization/drain pump flow rate, each
pump 500 gpm
Neutralization/drain pump motor power,
each pump 10 hp
Time to drain neutralization tank 30 min
UF CIP/EFM Residuals Estimates
Average CIP waste flow 6,300 gpd
CIP duration, total 4 to 6 hr
CIP chemical solutions, per CIP 1. Chlorine 2. Citric Acid (C6H8O7)
CIP waste volume per CIP chemical
solution 11,100 gal
CIP waste volume per CIP total 22,200 gal
Average MC waste flow 35,500 gpd
MC duration, total Up to 90 min
MC waste volume per clean, total 11,100 gal
CIP/MC waste flow from neutralization
tanks to drain, total 1,000 gpm
UF compressed air system
Compressors duty 1
Compressors standby 1
Compressor type Rotary screw compressor
Compressor size, each 15 kW
Air receivers duty 1
Air receivers standby 1
Air receiver pressure rating 200 psi
Air receiver operating pressure 100 - 150 psi
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Table 3-14: RO Design Parameters.
System Component Design Value Unit
RO Feed Tank
Number of tanks 1 Available volume for operational
equalization, minimum 8,000 gal
Residence time, minimum 15 min
Available volume required for
minimum residence time 220,000 gal
Total water volume (including
submergence) 235,000 gal
Total residence time 18.4 min
Cartridge Filters Main
On duty 3
On standby 1
Flow per vessel 4,246 gpm
Vessel configuration Horizontal
Vessel pressure rating 150 psi
Cartridges per vessel 32
Cartridge rating 5 m
Cartridge material Polypropylene
Cartridge diameter 6 in
Cartridge length 40 in
RO System Flow Stream pH and
Chemical Doses
pH Ranges
UF filtrate 6.7 - 7.7
RO feed (dosed) 6.2 - 6.7
RO permeate (typical) 4.8 - 5.7
RO concentrate 7.0 - 7.5
Chemical Dosing
Antiscalant 1.0 - 5.0 mg/L
H2SO4 10 - 100 mg/L
RO Trains
RO Feed 18.3 mgd
RO Permeate 15.6 mgd
On duty 7
On standby 1
RO feed pump flow 1,820 gpm
RO feed pressure 100 - 225 psi
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System Component Design Value Unit
RO recovery 85%
RO CIP System
CIP tanks on duty 1
CIP tanks on standby 1
CIP tank volume 7,000 gal
CIP tank diameter 12 ft
CIP tank total height 10 ft
Heaters per CIP tank 2
CIP heat power 200 kW
Target CIP solution temperature 45 °C
CIP solution heating time 2 hr
Target CIP solution pH 2 or 11.5
Recirculation rate: Stage 1 3,600 gpm
Recirculation rate: Stage 2 1,800 gpm
CIP pumps on duty 2
CIP pumps on standby 1
CIP pump flow rate 900 gpm
CIP pump pressure 60 psi
Table 3-15: UV/AOP Design Parameters
System Component Design Value Unit
Reactors on duty 3
Reactors on standby 1
Oxidant type HOCl
Flow, design 15.6 mgd
Flow capacity per duty train 5.20 mgd
Minimum EED 0.2 kWh/kgal
Design EED 0.22 kWh/kgal
Minimum UV dose 850 mJ/cm2
Maximum operating pressure 30 psi
Head loss at full flow 4 in
Minimum UVT 96 %
Oxidant Dosing
Oxidant Dosing Free chlorine (HOCl)
Oxidant dose, design 2 mg/L as Cl2
Oxidant dosing system, minimum 2 mg/L as Cl2
Oxidant dosing system, maximum 5 mg/L as Cl2
Chemical Addition NaOCl
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System Component Design Value Unit
Strength of solution 6.9 %
Product Water Tank HRT Volume (gal) HRT at Full
Capacity (min)
CO2 injection box 40,000 3.7
Lime injection box: 2 boxes on line 22,000 2.0
Lime injection ox: 1 box off line 11,000 1.0
Pump wet well 35,000 3.2
CO2 Storage
Storage time: worst-case conditions 4 days
Tanks 2
CO2 transfer efficiency 95 %
CO2 dose: max 90 mg/L
CO2 feed rate: max (actual) 26,886 lb/d
Net capacity: max conditions, per
tank 24 metric ton
Lime Silo
Diameter 12 ft
Height 30 ft
Storage capacity per tank 3,393 ft3
Design total storage capacity 6,786 ft3
FAT+O3/BAF AWTF Footprint
The assumed AWTF for this option will require a total area of approximately 286,100 ft2 (6.6 acres). Table
3-16 summarizes the individual footprint for the equipment requirement for each process and administration
and electrical building, roadway, and parking. Figure 3-3 shows the tentative location of the AWTF on
EWA’s South Parcel.
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Table 3-16: Footprint of FAT + O3/BAF AWTF
Process Footprint (ft2)
LOX System 2,000
Ozone System 6,400
BAC Filters 15,000
UF Trains 16,000
RO Trains 18,000
CIP System 2,000
UV System 3,600
Electrical Rooms 5,000
Electrical Building 9,000
Product Water Tank 14,700
CO2 Dosing System 2,000
Lime Dosing System 3,000
Chemical Storage 11,300
Pump Station 12,100
Admin. / Maint. Building1 14,000
Parking 27,000
Roadway/ 125,000
Total 286,100
Footnotes:
1. The administration building area includes offices, conference rooms, exhibit space, maintenance shops and
storage, control room, water quality laboratory, lunch room, restrooms, showers, and of miscellaneous storage
space.
2. Rounded to the nearest 100.
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Figure 3-3: Representative Layout of the O₃/BAF + FAT AWTF on EWA’s South Parcel (Far View).
3.5.3 WTP for Treated Drinking Water Augmentation
The purified water from the O₃/BAF + FAT treatment facility would be sent to an ESB + Cl2. The assumed
residence time is thirty minutes before being treated by UF system. Due to the highly-treated feed water
quality, the UF would be able to operate at a higher flux (120 gfd). Table 3-17 provides a summary of the
design criteria for the ESB and the UF system.
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Table 3-17. Design Criteria for ESB-Cl2 + UF System
System Component Design Value Unit
Oxidant Dose
Oxidant dose, design 2 mg/L as Cl2
Oxidant dosing system, minimum 2 mg/L as Cl2
Oxidant dosing system, maximum 6 mg/L as Cl2
Effluent Chlorine Residual 3 mg/L as Cl2
Chemical Addition NaOCl
Strength of solution 12.5 %
Engineered Storage Buffer
Retention Time 2 hours
Volume per tank 173,708 ft3
Tank Water Height 40 ft
Diameter of tank 74 ft
Number of tanks 3 (fill, hold, draw)
Length of ESB area 253 ft
Width of ESB area 94 ft
Ammonia Dosing System
Ratio NH3-N:Cl2 1:5
Dose 1 mg/L
Loading 130 lb/day
Aqua Ammonia Concentration 19 %
UF
Membrane area / module 775 ft2
System rated capacity (filtrate flow) 15.44 mgd
Feed flow 15.59 mgd
Assumed Recovery 99 %
Number of racks 6
Number of membrane modules per rack, installed 28
Number of membrane modules per rack, total available 37
Design flux, instantaneous 120 gfd
FAT+O3/BAF AWTF plus WTP Footprint
The assumed AWTF for this option will require a total area of approximately 324,400 ft2 (7.4 acres). Table
3-18 summarizes the individual footprint for the equipment requirement for each process and administration
and electrical building, roadway, and parking. Figure 3-4 shows the tentative location of the AWTF on
EWA’s South Parcel.
Table 3-18: O₃/BAF + FAT + WTP for Treated Drinking Water Augmentation Footprint
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Process Footprint (ft2)
LOX System 2,000
Ozone System 6,400
BAC Filters 15,000
UF Trains 16,000
RO Trains 18,000
CIP System 2,000
UV System 3,600
Engineered Storage Buffer 15,600
High-Flux UF 800
Electrical Rooms 5,000
Electrical Building 9,000
CO2 Dosing System 2,000
Lime Dosing System 3,000
Chemical Storage 11,300
Product Water Tank 14,700
Pump Station 14,000
Admin. / Maint. Building1 14,000
Parking 27,000
Roadway 145,000
Total 324,400
Footnotes:
1. The administration building area includes offices, conference rooms, exhibit space, maintenance shops and
storage, control room, water quality laboratory, lunch room, restrooms, showers, and of miscellaneous storage
space.
2. Rounded to the nearest 100.
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Figure 3-4: Representative Layout of the O₃/BAF + FAT + WTP on EWA’s South Parcel (Far View).
3.5.4 Future AWTF Expansion Footprint
A future expansion of the FAT+O3/BAF AWTF from 16 mgd to 25 mgd was evaluated for space planning
purposes. This option will require a total area of approximately 389,600 ft2 (8.9 acres). Table 3-19
summarizes the individual footprint for the equipment requirement for each process and administration and
electrical building, roadway, and parking. Figure 3-5 shows the tentative location of the AWTF on EWA’s
South Parcel.
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Table 3-19. Footprint of FAT + O3/BAF AWTF at 25 mgd
Process Footprint (ft2)
LOX System 3,100
Ozone System 7,200
BAC Filters 17,000
UF Trains 19,000
RO Trains 28,200
CIP System 3,600
UV System 5,600
Electrical Rooms 5,000
Product Water Tank 22,900
CO2 Dosing System 2,000
Lime Dosing System 3,000
Chemical Feed System/Storage 11,300
Electrical Building 9,000
Pump Station 21,000
Admin./ Maint. Building1 23,000
Parking 68,200
Roadway 140,500
Total 389,600
Footnotes:
1. The administration building area includes offices, conference rooms, exhibit space, maintenance shops and
storage, control room, water quality laboratory, lunch room, restrooms, showers, and of miscellaneous storage
space.
2. Rounded to the nearest 100.
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Figure 3-5: Representative Layout of the O₃/BAF + FAT AWTF Expansion (25 mgd) on EWA’s
South Parcel.
Conceptual Costs for Advanced Treatment
3.6.1 Capital Costs
Based on the conceptual design assumptions listed above, a Class 4 Budget Estimate was performed. This
conceptual cost estimate includes all the components of the advanced water treatment plant (i.e., UF, RO,
AOP, and additional equipment including pumps, administrative building, brine disposal, engineering,
taxes, shipping, and site work. This estimate does not include the estimated costs and any footprint needed
for finished water conveyance or integration with the potable reuse receptor, which is discussed in Sections
4 and 5 below. The cost estimate also does not include potential brine treatment; however, it does include
a pressurized brine pipeline from the AWTF to the Encina Ocean Outfall (connection assumed to be made
immediately upstream of the final secondary effluent sampling station).
The AWTF cost estimates are provided in Appendix A and are summarized as follows:
• FAT AWTF: capital cost of $164,000,000.
• FAT with O₃/BAF: capital cost of $235,000,000.
• FAT with O₃/BAF and WTP: capital cost of $284,000,000.
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3.6.2 O&M Costs
Operation and maintenance (O&M) costs include power cost (at $0.15 per kWh), chemical costs, and
replacements of consumables (membranes, filter media, UV lamps and ballasts, RO cartridge filters, and
RO membrane elements). Maintenance costs are included for each of the systems in the treatment train,
product water conditioning, chemical system and electrical equipment. Annual labor costs were based on
four full-time employees (FTEs) operating the facility working 2080 hours per employee per year for the
FAT AWTF, six FTEs for the FAT with O₃/BAF AWTF, and seven FTEs for the FAT with O₃/BAF and
WTP AWTF.
The O&M costs are provided in Appendix A and are summarized as follows:
• FAT AWTF: O&M cost of $7,000,000.
• FAT with O₃/BAF: O&M cost of $8,600,000.
• FAT with O₃/BAF and WTP: O&M cost of $9,900,000.
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4 Conveyance Concepts
Introduction
The purpose of this section is to develop the concepts for conveyance within the three proposed options to
be further evaluated as part of this report:
• Option F - Carlsbad Desalination Plant product water pump station (North)
• Option G - San Dieguito Reservoir, Groundwater Basin and SDCWA Second Aqueduct
Augmentation (South)
• Option H - San Marcos Groundwater Basin and SDCWA Second Aqueduct Augmentation (East)
For each option, a preliminary hydraulic evaluation was conducted to determine approximate pipe size,
pressure requirements, pumping requirements, and a preliminary opinion of construction costs. A summary
of each Option’s hydraulics is provided in Figure 4-1.
4.1.1 Pipeline Alignment Assumptions
Conveyance alignments were selected with input from stakeholders and are based on the shortest right-of-
way corridors from the proposed Encina Advanced Water Treatment Facility (AWTF) to the San Diego
County Water Authority (SDCWA) aqueduct and did not consider utilities and other constructability
constraints nor environmental impacts. Pipeline routes within existing easements, such as overhead
electrical transmission easements, were not considered. A detailed alignment evaluation should be
conducted if the project moves forward as part of a preliminary design phase.
4.1.2 Hydraulic Requirement Assumptions
Due to changes in elevation and the high pressure requirements, multiple pump stations are assumed for
this analysis to avoid pressures greater than 400 psi throughout miles of pipeline. It is assumed that for each
SDCWA turnout, a smaller booster station can be constructed to adequately meet the pressure requirements.
A spreadsheet model and calculations were used to select pipe diameter, determine pumping requirements,
and pressure requirements. Flow velocity and pumping horsepower requirements were calculated for each
option and its segments.
• Nominal pipe diameter is used as the interior pipe diameter in the hydraulic calculations. Variance
in internal diameter based on pipe material were not considered.
• Elevation of the proposed conveyance pump station at the AWTF is estimated to be 55 feet above
mean sea level (MSL). Elevation and requirements of intermediate booster stations and discharge
elevations are noted below by Option.
• Headloss calculations are based on Hazen-Williams equation with a friction factor (C-value) of 130
for new pipe.
• Pumping efficiency is estimated to be 80%.
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Figure 4-1: Pumping Requirements Summary
Option F Carlsbad Desalination Plant Effluent Augmentation
EWA AWT - Pump Station Segment 1 Desal Plant Wet Well Desal Plant Pump Station
Flow:15.8 mgd Length:2.5 miles Flow:15.8 mgd Flow:15.8 mgd
Pump Sta:1,000 hp Pipe Size:30 inch Elevation:70 feet Pump Sta:8,000 hp
Pressure:61 psi Velocity:5.0 ft/s Pressure:40 psi Pressure:40 psi
Option G San Dieguito Reservoir + Groundwater Basin and SDCWA Aqueduct Augmentation
EWA AWT - Pump Station Segment 2 - future phase Booster Pump to SDCWA Segment 4 - future phase Turnout at Badger WTP
Flow:15.96 mgd Length:6.3 miles Flow:15.96 mgd Length:2.1 miles Flow:15.96 mgd
Pump Sta:1,200 hp Pipe Size:20 inch Pump Sta:4,800 hp Pipe Size:30 inch Elevation:460 feet
Pressure:73 psi Velocity:4.2 ft/s Pressure:314 psi Velocity:5.0 ft/s Pressure:209 psi
Segment 1 Segment 3 - exist pipe SD Reservoir Turnout
Length:8.3 miles Length:5.2 miles Flow:10 mgd
Pipe Size:30 inch Pipe Size:24 inch Elevation:240 feet
Velocity:5.0 ft/s Velocity:4.9 ft/s Pressure:46 psi
SEJPA WRF - Pump Station Segment 5 SD GWR Turnout
Flow:15.96 mgd Length:2.3 miles Flow:2 mgd
Pump Sta:3,200 hp Pipe Size:12 inch High Point:250 feet
Pressure:184 psi Velocity:3.9 ft/s Pressure:46 psi
Option H San Marcos Groundwater Basin and SDCWA Aqueduct Augmentation
EWA AWT - Pump Station Segment 1 Segment 2 San Marcos GWR Turnout
Flow:15.96 mgd Length:7.5 miles Length:2.7 miles Flow:2 mgd
Pump Sta:5,600 hp Pipe Size:30 inch Pipe Size:12 inch Elevation:580 feet
Pressure:345 psi Velocity:5.0 ft/s Velocity:3.9 ft/s Pressure:40 psi
SDCWA Turnout Booster Pump to SDCWA
Flow:13.96 mgd Flow:13.96 mgd
Elevation:570 feet Pump Sta:2,000 hp
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Option F – North
Option F will provide a maximum flow of 15.8 mgd from the proposed AWTF to the Carlsbad Desalination
Plant clearwell immediately upstream of the existing booster station for treated drinking water
augmentation. Pressure required at the clearwell air-gap is assumed to be 40 psi. The existing Desalination
Plant Pump Station will boost pressure to 533 psi to meet SDCWA requirements. The elevation of the
Desalination Plant is approximately 70 feet above MSL.
The clearwell at the Desalination Plant may be undersized and may be unable to accept additional flow.
Therefore, Option F includes additional costs for clearwell construction/expansion to allow for blending
and addition of baffling to provide mixing of the AWTF effluent with the desalinated product water.
Phasing Options:
• Option F1: full 15.8 mgd to a new clearwell at the Carlsbad Desalination Plant for integration with
the desalinated product water and distribution to the SDCWA potable water system via the
desalinated water pipeline. Project will include a new clearwell sized to provide 30 minutes of
storage capacity along with a new pump station to booster pressure to 533 psi to match existing
system pressure.
• Option F2: first phase of 5.1 mgd conveyed to the south for surface water augmentation at the San
Dieguito Reservoir (3.1 mgd) and groundwater augmentation in the San Dieguito Basin (2 mgd).
As a second phase, the remaining 10.7 mgd would be integrated with the desalinated product water
for treated drinking water augmentation as in Option F1 above. The pump station at the desalination
plant could be scaled down to match the 10.7 mgd flow, or could be kept at 15.8 mgd as in Option
F1 to allow flexibility of operations in determining which receptor to send the AWTF product water
to.
For the purposes of this section, Option F is assumed to consist only of Option F1, as the first phase of
Option F2 is discussed under Section 4.3 below. See Table 4-1 for this Option’s hydraulics summary. See
Table 4-2 for this Option’s pumping requirements.
Table 4-1: Pipeline Velocity and Headloss – Option F
Pipe Segment Flow Length Pipe
Diameter
Flow
Velocity
Pipe
Headloss
Option F – Carlsbad Desalination Plant Augmentation
1-Backbone to Desal Plant turnout 15.8 mgd 2.6 miles 30 in. 4.98 ft/s 34 ft
Table 4-2: Pumping Requirements – Option F
Option HGL Static
Head
TDH Hydraulic
Horsepower 1
Est. Total Station
Horsepower 2
Option F – Carlsbad Desalination Plant Augmentation
Pump at EWA AWTF 196 ft 15 ft 141 ft 500 hp 1,000 hp
Pump at Desal Plant
Wet Well 1300 ft 15 ft 1245 ft 4,000 hp 8,000 hp
Footnotes:
1) Hydraulic horsepower is the minimum actual motor horsepower for a single pump required to move the water
rounded up to the nearest 100 hp to meet the pumping requirements.
2) Total station horsepower is total motor horsepower and will depend on the number of pumps installed. A reasonable
estimate of total station horsepower considering standard motor sizes and standby pumps is twice the hydraulic
horsepower. For cost estimating purposes, two (2) duty pumps are assumed and one (1) standby pump.
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Length of pipeline from the proposed AWTF to the connection point to the Desalination Plant clearwell is
estimated to be 2.5 miles. This will provide approximately 45 minutes of travel time from the AWTF to the
Desalination Plant clearwell. Alignment crosses the I-5 Freeway via trenchless construction, then follows
Paseo del Norte to Cannon Road before crossing back across the I-5 Freeway via trenchless construction to
Avenida Encinas into the Desalination Plant property.
See Figure 4-2 for Option F proposed alignment. See Figure 4-3 for Option F proposed HGL.
Figure 4-2: Option F - Carlsbad Desalination Plant Augmentation Alignment
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Figure 4-3: Option F - Carlsbad Desalination Plant Augmentation HGL
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Option G – South
Option G will provide a maximum flow of 15.96 mgd from EWA AWTF to San Elijo Joint Power Authority
(SEJPA). A new pump station will be constructed at SEJPA to convey flows: 3.1 mgd will be discharged
to San Dieguito Reservoir for surface water augmentation, 2 mgd to San Dieguito Groundwater Basin for
groundwater injection, and 10.86 mgd to SDCWA Second Aqueduct for raw water augmentation.
An additional Pump Station will boost pressure from San Dieguito Reservoir turnout to the SDCWA turnout
to 208 psi to meet SDCWA requirements. Elevation of the SDCWA Second Aqueduct at the connection
location is approximately 670 feet above MSL. Elevation of the proposed discharge facility at San Dieguito
Reservoir is approximately 250 feet above MSL. Elevation of the proposed discharge facility at GWR is
approximately 100 feet above MSL.
Phasing Options:
• Option G1: First phase of 5.1 mgd conveyed to the south for surface water augmentation at the San
Dieguito Reservoir (3.1 mgd) and groundwater augmentation in the San Dieguito Basin (2 mgd).
• Option G2: Second phase of up to 15.96 mgd to the Second Aqueduct for raw water augmentation.
This would then form part of the supply for the Badger WFP, so surface water augmentation at the
San Dieguito Reservoir would no longer be required as in the first phase. Note that groundwater
augmentation in the San Dieguito Basin would continue at approximately 2 mgd; however, since
the water would be conveyed via the same pipeline, it would need to be at a quality suitable for raw
water augmentation.
See Table 4-3 for pipeline Option G hydraulics summary. See Table 4-4 for Option G Pumping
Requirements.
Table 4-3: Pipeline Velocity and Headloss – Option G
Pipe Segment Flow Length Pipe
Diameter 1
Flow
Velocity
Pipe
Headloss
Option G – San Dieguito Reservoir, Groundwater Basin & SDCWA Augmentation
1-Backbone to SEJPA WRF 15.96 mgd 8.3 mi. 30 in. 5.0 ft/s 110 ft
2-New Pipe to SD Reservoir 5.96 mgd 6.3 mi. 20 in. 4.2/ft/s 97 ft
3-Existing pipe to SD Reservoir 10.0 mgd 5.2 mi. 24 in. 4.9 ft/s 100 ft
4-Backbone to Badger WTP 15.96 mgd 2.1mi. 30 in. 5.0 ft/s 33 ft
5-Lateral to GWR at Via de la Valle 2.0 mgd 2.3 mi. 12 in. 3.9 ft/s 57 ft
Table 4-4: Pumping Requirements – Option G
Option HGL Static
Head
TDH Hydraulic
Horsepower 1
Est. Total Station
Horsepower 2
Option G – San Dieguito Reservoir, Groundwater Basin & SDCWA Augmentation
Pump at EWA AWTF 223 ft -35 ft 168 ft 600 hp 1,200 hp
Pump at SEJPA WRF 444 ft 220 ft 424 ft 1,600 hp 3,200 hp
Pump at SD Reservoir 928 ft 210 ft 679 ft 2,400 hp 4,800 hp
Footnotes:
1) Hydraulic horsepower is the minimum actual motor horsepower for a single pump required to move the water
rounded up to the nearest 100 hp to meet the pumping requirements.
2) Total station horsepower is total motor horsepower and will depend on the number of pumps installed. A reasonable
estimate of total station horsepower considering standard motor sizes and standby pumps is twice the hydraulic
horsepower. For cost estimating purposes, two (2) duty pumps are assumed and one (1) standby pump.
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Segment 1 Pipeline alignment is 8.3 miles traveling south from EWA AWTF along Avenida Encinas to
San Batiquitos Lagoon which will be crossed via trenchless methods to La Costa Avenue. Alignment will
continue south along Vulcan Avenue, San Elijo Avenue, and Manchester Avenue to SEJPA WRF.
Segment 2 Pipeline alignment is 6.3 miles traveling east from SEJPA WRF along Manchester Avenue to
Encinitas Boulevard to El Mirlo to Via de Fortuna to El Montevideo ending at San Dieguito Reservoir.
Segment 3 Pipeline alignment is 5.2 miles utilizing the existing abandoned 30-inch San Dieguito Water
District pipeline from SEJPA WRF ending at San Dieguito Reservoir. Segment 4 Pipeline alignment is 2.1
miles traveling east from San Dieguito Reservoir along El Camino del Norte to Aliso Canyon Road ending
at Badger WTP.
Segment 4 Pipeline alignment is 2.3 miles traveling south from San Dieguito Reservoir along El
Montevideo to Paseo Delicias to Via de la Valle ending at proposed injection wells in the San Dieguito
Groundwater Basin.
See Figure 4-4 for Option G proposed alignment. See Figure 4-5 for Option G proposed HGL.
Figure 4-4: Option G Alignment Analysis
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Figure 4-5: Option G - San Dieguito Reservoir, Groundwater Basin & SDCWA Second Aqueduct Augmentation HGLs
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Option H - East
Option H will provide a maximum flow of 15.96 mgd from the AWTF to SDCWA Second Aqueduct for
raw water augmentation. There is potential for up to 2 mgd to be diverted via a branch off the main proposed
pipeline to the San Marcos Groundwater Basin for groundwater injection. Thus, all water produced at the
proposed AWTF would need to be at a quality suitable for raw water augmentation.
An additional Pump Station will boost pressure at SDCWA turnout to 208 psi to meet SDCWA
requirements. Elevation of the discharge at SDCWA is approximately 570 feet above MSL. Elevation of
the discharge at GWR turnout is approximately 580 feet above MSL.
See Table 4-5 for pipeline Option H hydraulics summary. See Table 4-6 for Option H Pumping
Requirements.
Table 4-5: Pipeline Velocity and Headloss – Option H
Pipe Segment Flow Length Pipe
Diameter 1
Flow
Velocity
Pipe
Headloss
Option H – San Marcos Groundwater Basin & SDCWA Augmentation
1-Backbone to SDCWA 15.96 mgd 7.5 mi. 30 in. 5.0 ft/s 101 ft
2-Existing Pipe to GWR 2.0 mgd 2.7 mi. 12 in. 3.9/ft/s 78 ft
Table 4-6: Pumping Requirements – Option H
Option HGL Static
Head
TDH Hydraulic
Horsepower 1
Est. Total Station
Horsepower 2
Option H – San Marcos Groundwater Basin & SDCWA Augmentation
Pump at EWA AWTF 848 ft 515 ft 796 ft 2,800 hp 5,600 hp
Pump at Turnout 883 ft 10 ft 493 ft 1,000 hp 2,000 hp
Footnotes:
1) Hydraulic horsepower is the minimum actual motor horsepower for a single pump required to move the water
rounded up to the nearest 100 hp to meet the pumping requirements.
2) Total station horsepower is total motor horsepower and will depend on the number of pumps installed. A reasonable
estimate of total station horsepower considering standard motor sizes and standby pumps is twice the hydraulic
horsepower. For cost estimating purposes, two (2) duty pumps are assumed and one (1) standby pump.
Length of pipeline from EWA AWTF to the connection point to the SDCWA turnout is estimated to be 7.5
miles. Alignment crosses the I-5 Freeway via trenchless construction, then follows Paseo del Norte to
Palomar Airport Road to San Marcos Boulevard ending at Rancho Santa Fe Road with a new SDCWA
turnout with booster station.
Segment 2 Pipeline alignment is 2.7 miles utilizing existing abandoned 12-inch Vallecitos Water District
pipeline along San Marcos Boulevard to Twin Oaks Valley Road ending at new proposed injection wells
in the San Marcos Groundwater Basin.
See Figure 4-6 for Option H proposed alignment. See Figure 4-7 for Option H proposed HGL.
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Figure 4-6: Option H Alignment.
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Figure 4-7: Option H - San Marcos Groundwater Basin & SDCWA Aqueduct #2 Augmentation HGL
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Conceptual Costs for Conveyance
An opinion of probable construction cost was developed based on the concept presented in this TM. The
cost estimate is a Class IV estimate. Table 4-7 provides a summary of the preliminary capital and O&M
cost estimates for the conveyance system for each Option at the full product water flows. Detailed
conveyance construction cost estimates are provided Appendix A.
Table 4-7: Conveyance & Receptor Integration Costs by Option
Option
Capital Cost
O&M
Costs Conveyance
(Pipe + Pump)
Receptor
Integration
F - Carlsbad Desalination Plant Effluent
Augmentation $39,000,000 $104,000,000 $17,100,000
G - San Dieguito Reservoir + Groundwater Basin
and SDCWA Augmentation $254,000,000 $33,000,000 $18,800,000
H - San Marcos Groundwater Basin and SDCWA
Augmentation $159,000,000 $21,000,000 $15,200,000
4.5.1 Capital Costs
Each potable water reuse option will require receptor integration according to the form of potable reuse:
Treated Drinking Water Augmentation (TDWA), Groundwater Augmentation (GWA), and Surface Water
Augmentation (SWA). The following summarizes the key capital cost assumptions for receptor integration
for each project concept in addition to conveyance pipelines and pumping:
• Option F – Carlsbad Desalination Plant Effluent:
o Project includes construction of a 350,000-gallon clearwell at the Desalination Plant to
allow for blending and addition of baffling to provide mixing of the AWTF effluent with
the desalinated product water. Assumes 30 minutes of clearwell storage. Includes 8,000 hp
pump station to match desalination plant effluent pressure requirements.
• Option G – San Dieguito Reservoir + Groundwater Basin and SDCWA Augmentation:
o For surface water augmentation, project includes turnout with dechlorination to Reservoir;
costs for surface water treatment are not included.
o For groundwater augmentation, project includes construction of two groundwater injection
wells, two extraction wells, and expansion costs for pre-treatment and RO treatment.
Expansion costs for brine disposal and product water conveyance are assumed to be
included in the planned groundwater desalination plant.
o For raw water augmentation, project includes pumping to meet turnout requirements;
treatment costs are not included.
• Option H – San Marcos Groundwater Basin and SDCWA Augmentation:
o For groundwater augmentation, project includes construction of two groundwater injection
wells and two groundwater extraction wells with wellhead treatment. Assumes RO
treatment is not required as TDS levels in basin are less than 750 ppm.
o For raw water augmentation, project includes pumping to meet turnout requirements;
treatment costs at downstream water plants are not included.
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4.5.2 O&M Costs
O&M costs assumes $0.15/kWh for pumping costs and 1% of pipeline construction costs for conveyance
infrastructure maintenance. Pumping power is based on total motor horsepower for the pump station.
• Option F – Carlsbad Desalination Plant Effluent:
o Project includes 1,000 hp pump station at the AWTF, and a new 8,000 hp pump station at
the desalination plant.
o Project includes 2.5 miles of piping to be maintained.
• Option G – San Dieguito Reservoir + Groundwater Basin and SDCWA Augmentation:
o Project includes 800 hp pump station at the AWTF, 3,200 hp pump station at SEJPA, and
a 4,800 hp pump station at the Badger WTP.
o Expansion of the groundwater desalination facility from 1 to 3 mgd, 2 injection wells, and
2 additional extraction wells.
o Project includes 29.1 miles of piping to be maintained.
• Option H – San Marcos Groundwater Basin and SDCWA Augmentation:
o Project includes 5,600 hp pump station at the AWTF and a 2,000 hp pump station at the
SDCWA turnout.
o 2 groundwater injection wells and 2 extraction wells.
o Project includes 10.3 miles of piping to be maintained.
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5 Purified Water Receptor Integration Concepts
Groundwater Augmentation
5.1.1 San Dieguito Basin Recharge (Option G) and San Marcos Basin
Recharge (Option H)
Reliability in potable reuse can be achieved in a number of ways. At one extreme, strategies can rely heavily
on the prevention of failures, namely, through the provision of redundancy in treatment. Alternatively,
reliability can be achieved by creating systems that are capable of consistently responding to failures, i.e.,
halting the distribution of off-spec water before it reaches consumers. In both cases, public health is
maintained by protecting consumers from contaminants. Most potable reuse systems utilize a combination
of these two strategies—failure prevention and failure response. Groundwater recharge, for example,
requires both (1) treatment and (2) the retention and passage of water through the environment. The
retention in the aquifer provides some additional treatment—e.g., 1-log of virus reduction credit per month
in the ground (see TM 1)—but also a significant period of time during which a project sponsor could detect
and respond to any upstream treatment excursion or failure. The degree to which these two components are
used—treatment and retention time—can be balanced in different ways. For this reason, the degree of
treatment is integral in determining the requirements for the aquifer.
Analyzing the groundwater recharge portions of Options G and H, the FAT treatment train provides
sufficient treatment to meet the 10-log protozoa requirements, but alone cannot fully achieve the 12-log
requirement for viruses (refer to Table 3-2). Accordingly, the groundwater recharge system will need to
rely on additional treatment in the aquifer to complete the 12-log requirement. This treatment train provides
the opportunity to engage in both groundwater spreading and injection. While spreading is allowable from
the standpoint of regulations, it is likely infeasible due to the large footprint necessary for spreading basins
and the density of development in the areas of the San Dieguito and the San Marcos Basins. For the
groundwater augmentation option, it is assumed that groundwater injection will be pursued. Furthermore,
because the treatment train alone cannot achieve the pathogen reduction credits, it is assumed that the water
will have a minimum 6-month residence time in the groundwater basin. This assumption allows the project
to comply with the 12-log virus requirement and is in line with the retention times provided by the majority
of the existing, permitted groundwater recharge projects. Hydraulic modeling is necessary to ensure that a
6-month residence time is reasonable for the 2 mgd intended for injection in both the San Dieguito and San
Marcos Basins.
Assuming there will be no phasing of the AWTF treatment train, the FAT treatment train will not be
sufficient as all three remaining options include either raw or treated drinking water augmentation and these
DPR elements will require more stringent treatment than the FAT treatment train provides. For this
scenario, we will assume the FAT treatment train with O₃/BAF addition will be implemented for the
purposes of analysis. Most of the same requirements discussed above will still apply, however the residence
time in the aquifer will no longer be needed for the purposes of achieving sufficient virus LRC. Referring
to Table 3-4, LRC of 15.9, 16.8, and 14.2 are expected for virus, Cryptosporidium, and Giardia,
respectively, for the FAT treatment train with O₃/BAF addition, irrespective of retention time in the aquifer
(excluding the addition of a WTP after the AWTF). To permit this portion of the project as an IPR project,
a 2-month residence time in the aquifer will still be necessary. Again, hydraulic modeling is necessary to
determine if a 2-month residence time is reasonable for the 2 mgd intended for injection.
Assuming that the water will be injected into the aquifer, the following facilities/equipment are necessary:
• Pipeline from AWTF to groundwater basin (as described in Section 4 - Conveyance Concepts)
• Pump stations
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• Injection wells and associated buildings
• Extraction wells
• Treatment facilities, which are expected to include RO treatment, as necessary, and disinfection
• Monitoring wells
Surface Water Augmentation
5.2.1 San Dieguito Reservoir Discharge and Blending (Options F + G)
To assess surface water augmentation (SWA) projects, the most important components of the draft
regulations pertain to (1) the retention time of the advanced treated water in the reservoir and (2) the dilution
and mixing therein. The retention time in the reservoir is calculated as the theoretical hydraulic residence
time on a monthly basis as follows:
𝑉𝑑𝑛𝑑
𝑄≥6 𝑚𝑚𝑚𝑠ℎ𝑠
Where:
𝑉𝑑𝑛𝑑= volume in the reservoir at the end of the month
Q = total outflow (withdrawals + overflow)
Assuming a 6-month V/Q, the San Dieguito Reservoir can only accommodate ~1 mgd of flow from the
AWTF2. However, while 6 months is the current minimum theoretical residence time in the reservoir for
SWA projects in draft regulations, it is likely that projects with residence times as low as 2 months will be
permitted, given additional treatment and redundancy. If 2-month residence time is used as the lower
bookend, the reservoir can accommodate ~3.1 mgd of advanced treated water1. This analysis assumes that
the advanced treated water is the only input to the reservoir, which is not currently the case.
In addition, the SWA project must meet dilution and mixing requirements. Currently, there are two
pathways to meet the mixing and dilution requirements based on the degree of treatment provided: 100:1
dilution in the reservoir and LRC of 12/10/10 for virus, Giardia, and Cryptosporidium, or 10:1 dilution and
provision of an additional 1-log removal of all three regulated pathogens (thus, final LRC of 13/11/11). For
this analysis, we will assume that a minimum dilution of 10:1 will be achieved, thus requiring the additional
1-log removal credit. Reservoir characterization, modeling, and tracer tests will be essential to determine
the extent of mixing and dilution in the reservoir. Numerous data inputs will be necessary for the modeling
team, including meteorological, water quality, and flow data. The most recent bathymetry evaluation was
completed 7 years ago and demonstrated the presence of significant solids build-up within the reservoir
(Anderson 2010). Updated bathymetry may be necessary given the high solids deposition rate (0.5 inches
per year). This would also be necessary following any future dredging and removal of solids from the
reservoir. The modeling results will provide important information to understand the mixing and dilution
in the reservoir, and the need for any engineered solutions to improve these characteristics. Tracer studies
to validate the model will also be necessary, per the draft requirements.
The log removal credits for a 2-month residence time project with 10:1 dilution will be at least 13/11/11, if
not significantly higher. LRC gained at the drinking water treatment plant downstream of the reservoir
count toward this 13/11/11 goal. Assuming the drinking water treatment plant provides the typical 4/3/2
log reductions, the AWTF would only be required to achieve LRC of 9/8/9 for an overall LRC of 13/11/11.
2 Capacity calculated using the following storage volume equation derived in (Anderson, 2010): Volume (acre-ft) = -
54.2 + 10.807*H – 0.7045*H2 + 0.01498*H3
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It is important to note that the only current project pursuing a 2-month retention time (the City of San
Diego’s Miramar Lake SWA project) is providing AWTF LRC of >20/>20/16, i.e., values in great excess
of 13/11/11.
For these reasons, it is likely that FAT treatment alone will not be sufficient for a 2-month project, even if
the project provides more than 9-logs (9.4-logs) of removal for virus (refer to Table 3-2). The proposed
train for a 2-month SWA project is therefore assumed to be equivalent to the one used by the City of San
Diego, namely, FAT treatment train with O₃/BAF pre-treatment. Referring to Table 3-4, LRC of 15.9, 16.8,
and 14.2 are expected for virus, Cryptosporidium, and Giardia, respectively, for the FAT treatment train
with O₃/BAF addition (without an additional WTP after the AWTF). This treatment train provides a high
degree of redundancy beyond 13/11/11.
As mentioned above, additional reservoir characterization is necessary to determine whether these V/Q and
dilution values are feasible in the San Dieguito Reservoir. The operation of the reservoir will also need to
be modified in a variety of ways to maximize its potable reuse capacity and to comply with regulations.
One significant assumption made in the V/Q calculations was that the only influent to the reservoir will be
advanced treated water; all other existing inflows, including flows from Lake Hodges, filter backwash water
from the Badger Water Filtration Plant, storm water runoff, and urban runoff, will need to be redirected. In
addition, it is likely that the reservoir will need to be specifically engineered to meet the dilution requirement
of 10:1. Engineering solutions likely to be relevant in the San Dieguito reservoir include optimizing
placement of the influent site relative to the extraction site, as well the implementation of equipment that
increases mixing in the reservoir to maximize dilution. The reservoir is currently operated using a diffused
aeration system, which facilitates a well-mixed, oxic state in the bulk water. Additional equipment
necessary for the implementation of a SWA project in San Dieguito reservoir could include the following:
• Diffusers
• Additional aeration equipment
• Floating baffles
Raw Water and Treated Drinking Water Augmentation
There are select examples of blending purified water with raw or finished water (e.g., Big Spring TX DPR
blending with raw surface water, CDP blending of purified water with other finished water). A recent
project funded by Water Research Foundation (WRF 4536) provides recommendations and guidance for
the appropriate use of blending as part of a DPR project, including evaluations of treatment, impact of
different water qualities, and corrosion control issues, impact on engineered storage, blending location, and
blending percentages (WRRF-13-15). There are key issues that should be addressed including (i) aesthetics;
(ii) regulated and emerging contaminants; (iii) microbiology; (iv) corrosion; and (v) location of blending
(WRRF- 13-15).
Aesthetics
Aesthetics challenges arises when blending water from multiple sources. Blending water from multiple
sources might cause changes in taste, odor color, turbidity, formation of scum, lack of lathering with soap
if hardness changes, etc. (Peet et al., 2001). Taste issues may be particularly important in RO-treated
recycled waters that lack hardness, alkalinity, and minerals. Bench or pilot-scale testing must be used to
evaluate the effects of blending because most of these parameters cannot be evaluated by the law of
mixtures or chemical theory. Maintaining the aesthetic quality of the water is a key issue when blending
water, because some consumers will relate the aesthetics of the water to its safety. With that said, stabilized
purified water (after chemical addition of minerals and pH adjustment) is consistently served to tour visitors
at the Orange County Water District, with high marks for flavor. The Big Spring TX DPR facility has been
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blending ~50% purified water (similar treatment to OCWD) with other surface waters, followed by a water
treatment plant, and has not experienced aesthetic challenges.
Regulated and Emerging Contaminants
Recycled water may contain more chemicals than conventional water supplies, depending upon the level
of recycled water treatment and the origin of existing raw water supplies. Of critical importance are those
pollutants that may present health risks, including regulated inorganic, radiologic, industrial, and pesticide
contaminants (Tchobanoglous et al., 2011). NWRI (2013) lists a number of chemicals of potential health
concerns that may be present in wastewater, including non-regulated contaminants, such as
pharmaceuticals, hormones, and consumer chemicals. Trussell et al. (2013) has determined the level of both
pathogen reduction and pollutant reduction needed for safe implementation of both IPR and DPR treatment,
and the use of UF/RO/UV AOP was proven to provide more than sufficient treatment. Other health and
risk evaluations have shown that such levels of purification provide a water quality that is equal or greater
in quality compared to conventional water supplies in the United States (NRC, 2012).
Disinfection byproducts remain an important item of water quality focus. NDMA and tri-halomethanes are
formed and destroyed in the purification process and can be properly managed to maintain concentrations
below regulated values. At the point of blending, the formation of these and other DBPs should be examined
through bench-scale studies to best understand the impact of disinfectant residuals, blending concentrations,
and TOC impacts (WRRF - 13-15).
Microbiology
Microorganisms that may remain in treated recycled water represent a threat to water quality. NRC (2006)
identified the high risks associated with regrowth in premise plumbing and the Centers for Disease Control
has acknowledged that opportunistic pathogens (OPs), such as Legionella, Pseudomonas, and
Mycobacterium, proliferating in building plumbing systems are now the primary source of waterborne
disease outbreaks (and a majority of associated deaths) in the U.S. (CDC, 2011; Brunkard et al., 2011).
Concerns are also emerging regarding the potential to spread antibiotic resistance genes (ARGs) via
microbial re-growth in water reuse systems, a topic that is of concern to policy makers in the U.S. and
world-wide (Fahrenfeld et al., 2013; Pruden, 2013; Wellington et al., 2013). Addressing knowledge gaps
related to opportunistic pathogens and antibiotic resistance will help to advance water reuse system design,
including water treatment and distribution, in order to minimize potential risks of emerging microbiological
constituents of concern. Regrowth of OPs, bacteria with ARGs, microbes influencing corrosion (MIC) and
indicator organisms such as heterotrophic plate counts (HPCs) is a function of many parameters including
disinfectant residual, type of disinfectant, temperature, nutrient concentrations, turbidity, pH, and alkalinity.
As it pertains to this evaluation, WRF 4536 is documenting the relative improvement in blended water
quality as a result of the use of purified water for blending (Salveson et al., in progress). Results clearly
document that higher percentages of purified water reduce the levels of microorganisms in the blended
water within the simulated distribution systems; a clear improvement in water quality.
Corrosion
Increased corrosiveness or aggressiveness of water following blending is another concerning issue. This
corrosion can be directly linked to corrosive water quality (e.g., RO permeate), or can be the result of
microbiologically induced corrosion. Microbial activity during stagnation has been linked to rapid loss of
disinfectant (Zhang and Edwards, 2009; Nguyen et al., 2012), contamination of potable water with high
levels of copper, lead and iron (McNeill and Edwards, 2001; Edwards et al., 2000; Zhang et al., 2009),
microbial corrosion failures (Videla, 1996) and aesthetic problems (taste and odor) of potable water (NRC,
2006). The corrosion influencing parameters that are most relevant to recycled waters are temperature, pH,
alkalinity, dissolved inorganic carbon, oxidants, total dissolved solids, calcium hardness, chloride, sulfate,
hydrogen sulfide, and natural organic carbon (Vik et al., 1996).
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As it pertains to this evaluation, the purified water will be stabilized and a chloramine residual will be
maintained prior to blending with other raw or finished water, minimizing the corrosion impacts.
Location of Blending
Another important aspect of blending water of different quality pertains to the location of blending.
Blending water of different quality may locally disrupt the natural “ecology” of the receiving environment.
Because of this, blending in a storage reservoir or within a treatment plant will have a different impact
compared to blending in the distribution system, as measured by biofilm detachment, or disruption of
passive protective scale layers. Depending on water quality, blending recycled water upstream of a WTP
may result in positive or negative impacts on the existing treatment processes. The State of California
Division of Drinking Water has expressed this very concern related to DPR integration. In other cases,
blending upstream of a water treatment plant can be expected to improve treated water quality, as in the
case of blending purified water, resulting in decreased total organic carbon, potentially leading to more
stable disinfectant residuals and reduced microbial growth feeding into a water treatment plant.
Pertaining to this project, the primary concern is the blending of purified water with other finished water,
which could result in a localized change to pipeline biofilms.
5.3.1 Second Aqueduct Raw Water Augmentation (Options G-H)
As part of another effort, the San Diego County Water Authority (SDCWA) considered the effects on water
quality of delivering water directly from the Carlsbad Desalination Plant (CDP) to the south and into the
SDCWA's aqueduct. A chemical injection facility was proposed at the San Marcos connection point to
assure water quality. It should be noted that this is not a normal operation mode and water from the
desalination plant is typically routed to the Twin Oaks Valley Water Treatment Plant (TOVWTP). The
chemical injection facility would inject sodium hypochlorite (11% - 14% solution) at a rate of 700 gal/day
and aqueous ammonia (17% - 20% solution) at a rate of 350 gal/day (SDCWA, 2006). In the fourth
addendum of the environmental impact report, additional modifications were made to ensure the desalinated
product water can be safely and reliably integrated into the distribution system.
The proposed Encina AWT facilities, as described previously, will use sodium hypochlorite as part of the
UV/AOP, leaving a free chlorine residual of 2 to 3 mg/L. The aqueous ammonia dosing station would likely
be installed at the new AWTF to combine with the free chlorine to create a stable chloramine residual. The
AWTF also will stabilize the purified water with a lime solution and neutralize the pH, making the new
water less aggressive. Overall, it is unlikely that any further chemical addition facilities will be needed at
the SDCWA blending location.
5.3.2 Carlsbad Desalination Plant Treated Drkinking Water Augmentation
(Option F)
SDCWA has experience blending water from the CDP with their other supplies. The desalinated water must
meet primary and secondary drinking water standards and does not differ significantly from the water
quality of the other sources of product water in the distribution. However, certain measures are taken to
prevent any possible effects on the water quality, aesthetics, and distribution system. The desalinated water
is chemically conditioned prior to delivery. The post-treatment stabilization for the RO product water
includes a combination of lime with carbon dioxide. Additionally, the desalinated water is then disinfected
using chloramines and blended with potable water, also disinfected with chloramines, from the
Metropolitan Water District. The blending of the desalinated water and the potable water does not result in
any measurable impacts related to water quality. Finally, the effects on the distribution system were
considered, because the existing water supply is delivered via gravity flow and delivering water from the
desalination plant will require continuous pumping to reach delivery points. This issue was addressed by
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modeling the potential effects and providing design features to minimize this effect by including surge
control facilities to avoid damage to water delivery facilities (SDCWA, 2014).
Pertaining to this project, blending of purified water (that has also been chemically stabilized) with other
water supplies in the region, such as with the CDP finished water, is not expected to have negative effects
on the combined finished water.
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6 Permitting Considerations and Brine Disposal
Permitting Overview
Although a variety of permits and approvals would be required for a potable reuse project (including
demonstration of CEQA compliance, construction-related permits, land use and/or coastal permits, air
quality permits, etc.), this TM focuses on the Regional Water Quality Control Board (RWQCB) and State
Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) permitting issues that
warrant early feasibility evaluation.
The RWQCB regulates the treatment, reclamation, and discharge of wastewater or recycled water through
federal NPDES (National Pollutant Discharge Elimination System) permits and State of California Waste
Discharge Requirements (WDRs). NPDES permits regulate discharges to federal surface waters3 pursuant
to requirements established within the federal Clean Water Act. In California, NPDES permits are issued
by the RWQCB under authority delegated by the U.S. Environmental Protection Agency (EPA). NPDES
permits are valid for up to five years, after which renewal of the permit is required. WDRs are issued by
the RWQCB to regulate discharges to state waters4 pursuant to provisions of the State of California Porter-
Cologne Water Quality Act.5 WDRs do not have an expiration date, but may be replaced or updated by the
RWQCB at any time.
NPDES permits and WDRs for proposed facilities would implement applicable federal and state water
quality plans and policies, including:
• The Water Quality Plan for the San Diego Basin (Basin Plan), which is applicable to all discharges
to ground and surface waters.6
• The Water Quality Control Plan, Ocean Waters of California (Ocean Plan), which is applicable to
all discharges to marine waters.7
3 Federal surface waters include inland surface waters and wetlands, estuaries, bays, and the Pacific Ocean.
NPDES permits regulate discharges to federal surface waters or tributaries to such surface waters.
4 State waters include both federal surface waters and groundwaters. NPDES permits issued by the RWQCB for
discharges to federal surface waters also double as WDRs, as the NPDES permits combine both federal and
state requirements into a single permit. Individual WDRs are issued for discharges to groundwater, as
groundwater discharges are regulated under state law but not federal law.
5 The Porter-Cologne Water Quality Act (as amended in 2017) preceded implementation of the federal Clean
Water Act, and includes the following portions of the California Water Code: Division 1, Sections 100-540;
Division 2, Sections 1000-5976, and Division 7, Sections 13000-16104.
6 The Basin Plan designates beneficial uses of ground and surface waters within the San Diego Region, and
establishes water quality objectives to protect the beneficial uses on a watershed-by-watershed basis. The Basin
Plan also establishes implementation policies for protecting beneficial uses and achieving the water quality
objectives.
7 The Ocean Plan establishes effluent and receiving water standards applicable for all discharges to State-
regulated waters of the Pacific Ocean (i.e., waters within three nautical miles of the shore). The Ocean Plan also
establishes requirements and implementation policies applicable to ocean discharges.
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• The California Toxics Rule (CTR), which is applicable to all discharges to federal inland surface
waters, enclosed bays, and estuaries.8
DDW acts as a consulting agency to the RWQCB, and the RWQCB incorporates all applicable DDW
recycled water, source water, discharge, and receiving water requirements within the NPDES permits or
WDRs that are issued by the RWQCB to discharging agencies. In addition, DDW also implements drinking
water standards and potable reuse requirements in the water supply permits issued by DDW to potable
water supply agencies.
6.1.1 RWQCB Permit Application Process
Dischargers must submit a Report of Waste Discharge (RWD) to the RWQCB in application for NPDES
permits or WDRs. The RWD consists of applicable permit applications forms; descriptions of proposed
facilities (including descriptive text, tables and figures); demonstrations of compliance with applicable
water quality plans and policies; and demonstrations of compliance with applicable environmental
regulations. The RWQCB is empowered to request any information, data, or studies needed to support
RWQCB assessment potential discharge compliance or impacts of the discharge. The RWQCB endeavors
to notify dischargers within 30 days of submission of the RWD as to whether the RWD is complete or if
supplemental information is required.
RWDs must be received by the RWQCB no later than 180 days in advance of the proposed discharge, but
RWQCB action on the submitted application may be delayed by RWQCB staff priorities and workloads. It
is advantageous to submit the RWD as soon as CEQA compliance is certified in order to eliminate
uncertainty on final RWQCB effluent concentration limits.9 In recent years, RWQCB workloads have been
such that processing of NPDES permits typically takes the entire 180-day period (or more). Processing of
WDRs, on the other hand, is often completed in significantly less time.
6.1.2 Required Permits for Reuse Options
Table 6-1 summarizes required RWQCB and DDW permits that would be required for reuse options
considered within TM3. As shown in Table 6-1, RWQCB permits required to implement the TM3 options
may include:
• WDRs to regulate the treatment and use of recycled water to recharge the San Dieguito Valley
Groundwater Basin (Option F and G) or the San Marcos Basin (Option H),
• a NPDES permit to regulate the discharge of purified water to San Dieguito Reservoir (Options F
and G).
In addition, modification of the existing Encina Ocean Outfall (EOO) NPDES permit would be required to
allow the discharge of AWTF waste brine to the EOO10. Modification of the EOO NPDES permit would
also be required to address any significant changes to Encina Water Pollution Control Facility (EWPCF)
onsite facilities that support implementation of any of the regional reuse options.
8 The California Toxics Rule (CTR) is established by EPA within Title 40, Section 131.38 of the Code of Federal
Regulations (CFR). The CTR establishes state-wide water quality standards for all discharges to inland surface
waters, enclosed bays, and estuaries.
9 The RWD can be submitted to the RWQCB prior to completing CEQA (and, if applicable, National
Environmental Protection Act) certification, but the RWQCB typically does not process the application until
after completion of the CEQA process. Regardless of the sequence of completion, information presented in the
RWD must be consistent with information presented within the CEQA documents.
10 Note that the EOO is used to discharge RO waste brine from the Carlsbad Water Reclamation Facility when the
RO system is in operation (e.g., to reduce salinity of the recycled water produced).
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Finally, modification of existing DDW water supply permits would be required for any water agency that
makes use of source water derived from EWA recycled water sources (e.g., groundwater augmentation,
surface water augmentation).
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Table 6-1: Anticipated RWQCB and DDW Permits for TM3 Reuse Options.
Option Activity
Type of Required Permit
RWQCB
NPDES
Permit11
RWQCB
WDRs12
DDW Water
Supply Permit
F
Groundwater augmentation (up to 2 mgd) in
San Dieguito Valley Groundwater Basin ●
●13, 15
Surface water augmentation (up to 3.1 mgd)
in San Dieguito Reservoir ●14
Treated drinking water augmentation (10.7 to
15.8 mgd) with Desalination Plant finished
water
See note15 See note12
Brine discharge to Encina Ocean Outfall ●16
G
Groundwater augmentation (up to 2 mgd) in
San Dieguito Valley Groundwater Basin ●
●13, 15 Surface water augmentation (up to 3.1 mgd)
in San Dieguito Reservoir ●14
Raw water augmentation (10.9 to 14 mgd) in
the Second Aqueduct Pipeline No. 5 See note12 See note12
Brine discharge to Encina Ocean Outfall ●13
H
Groundwater augmentation (up to 2 mgd) in
San Marcos Basin ●
●12, 15 Raw water augmentation (14 to 16 mgd) in
Second Aqueduct Pipeline No. 5 See note12 See note12
Brine discharge to Encina Ocean Outfall ●16
11 The RWQCB would adopt the NPDES permit pursuant to authority delegated by EPA. The NPDES permit
would implement applicable state and federal water quality plans, policies, and standards. The
treating/discharging agency would be the NPDES permittee.
12 WDRs would be adopted by the RWQCB pursuant to the State of California Porter-Cologne Water Quality Act.
The WDRs would implement applicable state water quality plans, policies, and standards. The
treating/discharging agency would be the NPDES permittee.
13 Modification of existing DDW water supply permits would be required for any agency issued to the Santa Fe
Irrigation District (operator of San Dieguito Reservoir) would be required.
14 NPDES permit would address the treatment and discharge of purified water to San Dieguito Reservoir, and
would implement applicable Basin Plan water quality standards for the reservoir as well as statewide water
quality standards established by the EPA California Toxics Rule.
15 Regulations governing direct potable reuse (DPR) have not been developed, but Senate Bill 918 directs the
SWRCB to convene an expert panel and investigate the feasibility of developing uniform water recycling
criteria for DPR projects. As documented in TM1, the SWRCB in a draft report released in 2016 determined
that “it is technically feasible to develop uniform water recycling criteria for DPR in California, and that those
criteria could incorporate a level of public health protection as good as or better than what is currently provided
by conventional drinking water supplies and IPR.”
16 Modification of the existing Encina Wastewater Authority NPDES permit (NPDES CA0107395) would be
required to address the discharge of brine to the EOO. The brine discharge NPDES modifications would
implement applicable Ocean Plan water quality standards.
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6.1.3 DPR Permitting Issues
As noted in Table 6-1, DPR regulations are not currently in place that would allow the use of purified water
to augment either (1) treated supplies in the CDP product water pipeline, or (2) raw water supplies in the
SDCWA Second Aqueduct Pipeline No. 5. As a result, it is uncertain how these treated or raw water
augmentation discharges would be regulated. Because directing purified recycled water to the Carlsbad
Desalination Project product water pipeline would not involve a discharge to federal surface waters,
however, it is probable that the RWQCB and DDW would regulate purified water treatment operations
through the following:
• RWQCB issuance of WDRs to recycled water agencies that incorporate applicable DDW-mandated
DPR requirements, and
• requirements established by DDW within water supply permits issued to water purveying agencies.
Because raw water augmentation would allow for discharge to imported water storage reservoirs, it is
probable that raw water augmentation to the SDCWA Second Aqueduct would be regulated through the
following:
• RWQCB issuance of a NPDES permit to the recycled water (discharging) agency that incorporates
applicable DDW-mandated DPR requirements, and
• requirements established by DDW within the water supply permits issued to water purveying
agencies.
Groundwater Augmentation
As shown in Table 6-1, groundwater recharge within the San Dieguito Valley Groundwater Basin (Options
F and G) or San Marcos Basin (Option H) would be regulated by RWQCB issuance of WDRs that
implement applicable DDW groundwater recharge regulations and RWQCB groundwater quality
objectives established within the Basin Plan. DDW regulations governing the use of recycled water for
recharging potable groundwater basins are established in Title 22, Division 4, Chapter 3 of the California
Code of Regulations (CCR). As detailed within TM1, DDW groundwater recharge regulations establish
requirements governing, in part:
• source control,
• level of treatment, recharge methods, and pathogen removal,
• diluent (dilution) water and recycled water contribution,
• recycled water (underground) retention times,
• restrictions on the construction of new groundwater wells within the restricted zone,
• tracer and treatment performance studies, and
• monitoring.
DDW acts as a consulting agency within the RWQCB permitting process, and the RWQCB will implement
DDW-mandated requirements17 directly into the WDRs governing the recycled water treatment and
groundwater recharge operations. As noted, DDW will also implement the groundwater recharge
regulations within the Water Supply Permits issued to each applicable water agency that would derive
potable supply from the affected groundwater basin.
In addition to implementing the DDW recycled water groundwater recharge requirements established
within Title 22, WDRs issued by the RWQCB would implement applicable prohibitions, requirements, and
17 See TM1 for a summary of DDW groundwater recharge regulations and requirements.
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water quality objectives established within the Basin Plan. Table 6-2 summarizes Basin Plan groundwater
quality objectives for mineral constituents for the San Dieguito Valley Groundwater Basin (Option F and
G) and the San Marcos Basin (Option H). Purified recycled water that complies with DDW treatment
requirements should readily comply with applicable Basin Plan groundwater quality objectives.
In addition to the objectives for mineral constituents listed in Table 6-2, the Basin Plan also applies DDW
primary drinking water Maximum Contaminant Levels (MCLs) directly to groundwaters of the San
Dieguito Valley and San Marcos Basin. As a result, WDRs issued by the RWQCB will likely prohibit
recycled water used for groundwater recharge from exceeding the potable water MCLs. The DDW water
supply permit, on the other hand, will apply the MCLs to the finished blended potable water supply.
Table 6-2: Basin Plan Groundwater Quality Objectives.
Constituent
Basin Plan Groundwater Quality Objective
(mg/L)18
San Dieguito Valley
Groundwater Basin San Marcos Basin
Total dissolved solids, TDS 1500 1000
Chloride 500 400
Sulfate 500 500
Nitrate (as NO3) 45 45
Iron 0.85 0.3
Manganese 0.15 0.05
Boron 0.75 0.75
Fluoride 1.0 1.0
Surface Water Augmentation
The use of recycled water for surface water augmentation of San Dieguito Reservoir (Options F and G)
would be regulated by RWQCB issuance of a NPDES permit to the recycled water treatment and
discharging agency. The NPDES permit would implement applicable DDW potable reuse regulations as
well as applicable state and regional surface water quality objectives.
As discussed in TM1, DDW has issued uniform regulations governing the use of recycled water for
augmenting supplies within surface water reservoirs that serve as a source of raw water supply to potable
water treatment plants. Initial draft surface water augmentation regulations were distributed by DDW for
public comment in mid-2017.19 As summarized in TM1, the draft DDW potable reuse regulations address
requirements for:
• source control,
• advanced treatment and pathogen removal,
18 Basin Plan groundwater quality objective not to be exceeded more than 10 percent of the time. It is probable
that the RWQCB will establish effluent concentration limits for groundwater recharge projects at the listed
objective.
19 Draft proposed regulations released by DDW in 2017 (dated October 12, 2016) include revisions to the
following sections of Title 22, Division 4 of the California Code of Regulations: Chapter 3, Article 1 (Section
60301); Chapter 3, Article 5.3 (Section 60320); and Article 9 (Section 64668).
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• reservoir dilution,
• reservoir retention,
• reservoir modeling and tracer studies,
• emergency and operations plans to ensure reliability, and
• ongoing performance monitoring.
DDW potable reuse regulations will be incorporated in the NPDES permit issued by the RWQCB to the
recycled water treatment agency as well as the water supply permit issued by DDW to the reservoir operator.
Additionally, the NPDES permit that regulates the discharge of purified water to San Dieguito Reservoir
would establish purified water concentration standards that implement:
• state and federal water quality standards20 for San Dieguito Reservoir that are established by the
RWQCB within the Basin Plan, and
• state-wide standards for inland surface waters that have been imposed by EPA within the California
Toxics Rule (CTR).21
The Basin Plan establishes surface water quality standards within the San Diego Region on a watershed-
by-watershed basis. Basin Plan water quality standards for San Dieguito Reservoir watershed are
established for:
• mineral constituents such as total dissolved solids, chloride, sulfate, manganese, iron, boron, and
fluoride,
• nutrient constituents (total nitrogen and total phosphorus), and
• toxic constituents for which state and federal primary drinking water standards have been
established.
6.3.1 Basin Plan Standards
Table 6-3 summarizes Basin Plan surface water quality objectives for mineral constituents for San Dieguito
Reservoir. Because the purified water used for surface water augmentation would be required (per DDW
regulations) to undergo full reverse osmosis treatment, compliance with the Basin Plan mineral standards
is not projected to represent a compliance concern.
The Basin Plan establishes a narrative objective that concentrations of nitrogen and phosphorus, by
themselves or in combination with any other nutrient, shall be maintained at levels below those that
stimulate algae and emergent plant growth. As shown in Table 6-3, the Basin Plan also establishes
numerical concentration objectives for total phosphorus. While Basin Plan concentration objectives for total
phosphorus are stringent, phosphorus is readily removed through advanced treatment and compliance with
the Basin Plan standard for total phosphorus should not represent a compliance concern for the level of
treatment mandated under proposed DDW surface water augmentation regulations.
20 Basin Plan water quality objectives for surface waters have been adopted by EPA as federal water quality
standards that are subject to requirements and enforcement provisions of the federal Clean Water Act.
21 CTR regulations were promulgated by EPA within 40 CFR 131.38. (EPA, 2000).
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Table 6-3: Basin Plan Surface Water Quality Objectives for San Dieguito Reservoir
Constituent
Basin Plan Surface Water
Quality Objective (mg/L)22
San Dieguito Reservoir
Total dissolved solids, TDS 500
Chloride 250
Sulfate 250
Iron 0.3
Manganese 0.05
Boron 0.75
Fluoride 1.0
Total Phosphorus 0.02523
Total Nitrogen See Note24,25
Total nitrogen, on the other hand, is not completely removed through advanced treatment and would
represents a significant compliance concern for a surface water augmentation project at San Dieguito
Reservoir. The Basin Plan requires that “natural” N:P ratios are to be identified and upheld, and that in the
absence of data, a N:P ratio of 10:1 is to be used. Applying a 10:1 N:P ratio to the 0.025 mg/L Basin Plan
standard for total phosphorus would result in a total nitrogen concentration limit of 0.25 mg/L – a value
that cannot readily be achieved even with 100 percent reverse osmosis treatment.
To address this issue, after initial review of two local surface water augmentation projects26, the RWQCB
has tentatively agreed to a surface water augmentation regulatory concept under which purified water
discharges to imported water reservoirs could be regulated through:
22 Basin Plan groundwater surface water quality objective not to be exceeded more than 10 percent of the time. It
is probable that the RWQCB will establish NPDES effluent concentration limits for surface water augmentation
discharges at the listed objective.
23 Threshold total phosphorus (P) shall not exceed 0.05 mg/L in any stream at the point where it enters any
standing body of water, nor 0.025 mg/L in any standing body of water.
24 The Basin Plan does not establish analogous concentration values for total nitrogen, but requires that natural
ratios of nitrogen to phosphorus (N:P) are to be identified through monitoring and upheld. In the absence of
data, the Basin Plan specifies that a N:P ratio of 10:1 is to be used. If applied to San Dieguito Reservoir, such a
10:1 N:P ratio would translate to a total nitrogen standard of 0.5 mg/L in discharges to standing bodies of water,
and a nitrogen standard of 0.25 mg/L within the ambient reservoir water.
25 In indirect potable reuse (IPR) projects proposed by the City of San Diego for Miramar Reservoir and by the
Padre Dam Municipal Water District and Helix Water District for Lake Jennings, the RWQCB has indicated a
willingness to consider imposing total nitrogen standards on the order of 2 mg/L for purified recycled water
discharges to these reservoirs. The basis for this consideration is that “natural” N:P ratios do not exist in
reservoirs that are dominated by imported water or by IPR water. Instead, N:P ratios are dependent on the
source and quality of the imported water supply. Consequently, operators of such reservoirs can manage and
maintain N:P ratios at sufficiently high values to ensure that phosphorus remains the limiting nutrient and the
limited phosphorus concentrations prevent adverse biostimulation effects.
26 The City of San Diego has proposed the use of purified recycled water for supplying Miramar Reservoir, and
the Padre Dam Municipal Water District and Helix Water District have proposed the use of purified recycled
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• recycled water treatment to ensure compliance with the Basin Plan 0.025 mg/L total phosphorus
objective, and
• ensuring that phosphorus-limited conditions (e.g. maintaining a high N:P ratio) are maintained
within the reservoir to prevent biostimulation.
Additional study will be required to determine if the tentative nutrient compliance proposed for Miramar
Reservoir and Lake Jennings is workable at San Dieguito Reservoir. It is probable that this approach will
only be feasible if purified water completely replaces Lake Hodges water as the source of supply within
San Dieguito Reservoir.27
6.3.2 Application of Drinking Water Standards
In addition to establishing standards for mineral constituents, the Basin Plan imposes state and federal
primary drinking water standards on raw waters stored in San Dieguito Reservoir. As a result, while DDW
applies the drinking water standards to the final potable supply, the RWQCB applies the state and federal
primary drinking water concentration standards to the untreated source water waters within the watershed.
6.3.3 California Toxics Rule
EPA in 2000 promulgated the California Toxics Rule (CTR) which established state-wide water quality
standards for inland surface waters of California.28 CTR standards have been established for toxic inorganic
and toxic organic constituents for the protection of aquatic habitat and for the protection of public health.
The CTR standards also incorporate national standards for toxic chemicals established by EPA within the
National Toxics Rule (NTR).29
Table 6-4 presents CTR standards for the protection of aquatic habitat that would be applicable to San
Dieguito Reservoir. Table 6-5 presents CTR standards for the protection of public health. Since San
Dieguito Reservoir is closed to public access and fishing, only the CTR standards for the consumption of
water would apply to the reservoir.
As shown in Table 6-4 and Table 6-5, CTR standards for some toxic constituents are more stringent than
corresponding drinking water standards. As a result, the CTR concentration limits (rather than drinking
water limits) would govern purified water treatment and production for these constituents.
water for supplying Lake Jennings. The RWQCB has tentatively provided verbal agreement with a phosphorus-
limited approach for the Miramar Reservoir and Lake Jennings surface water augmentation projects that would
allow for total nitrogen effluent standards on the order of 2 mg/L. The RWQCB to date, however, has not
formally committed in writing to any particular tentative NPDES permit limits for these projects.
27 Lake Hodges receives significant nutrient contributions from its watershed, and it may not be possible to
manage or properly control nutrient concentrations in San Dieguito Reservoir if Lake Hodges supply continues
to be introduced in San Dieguito Reservoir. On the other hand, if the Lake Hodges supply is 100 percent
replaced by purified recycled water (e.g. no Lake Hodges water to San Dieguito), management of nutrient
conditions within San Dieguito Reservoir will be greatly simplified and it is probable that the RWQCB would
entertain total nitrogen standards on the order of 2 mg/L – standards that would be consistent with those being
considered by the RWQCB for proposed potable reuse projects at Miramar Reservoir and Lake Jennings.
28 Title 40, Section 131.38 of the Code of Federal Regulations (40 CFR 131.38). (EPA, 2000)
29 NTR standards are promulgated by EPA within 40 CFR 131.36. (EPA, 1993)
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It should be noted that CTR standards apply to ambient receiving waters, and SWRCB implementation
policies allow the RWQCB to apply the CTR standards outside designated mixing zones.30 As a result,
where appropriate dilution and mixing documentation is provided, the RWQCB may consider dilution
credits in establishing CTR-based NPDES effluent concentration standards.
Table 6-4: California Toxic Rule Standards for the Protection of Aquatic Habitat
Constituent
Concentration (µg/l)
Standard for Protection
of Aquatic Habitat31
Constituent
Concentration (µg/l)
Standard for Protection
of Aquatic Habitat28
CMC32 CCC33 CMC29 CCC30
TOXIC INORGANIC CONSTITUENTS CHLORINATED PESTICIDES
Antimony NS NS Aldrin 3.0 NS
Arsenic 340 150 gamma BHC
(Lindane) 0.95 NS
Cadmium 4.334 2.231 Chlordane 2.4 0.0043
Chromium III 55031 18031 4,4'-DDT 1.1 0.001
Chromium VI 16 11 4,4'-DDD NS NS
Copper 1331 931 4,4'-DDE NS NS
Lead 6531 2.531 Dieldrin 0.24 0.056
Mercury 1.4 0.77 alpha Endosulfan 0.22 0.056
Nickel 470 52 beta Endosulfan 0.22 0.056
Selenium NS 5.0 Endosulfan Sulfate NS NS
Silver 3.431 NS Endrin 0.086 0.036
Thallium NS NS Endrin Aldehyde NS NS
Zinc 12031 12031 Heptachlor 0.52 0.0038
Cyanide 22 5.2 Heptachlor Epoxide 0.52 0.0038
ACID EXTRACTABLE COMPOUNDS PCBs NS 0.014
Pentachlorophenol 19 15 Toxaphene 0.73 0.0002
Footnotes:
1. NS indicates that no standard has been established for the listed constituent.
30 The SWRCB established CTR implementation policies within Policy for Implementation of Toxics Standards
for Inland Surface Waters, Enclosed Bays, and Estuaries of California. (SWRCB, 2005)
31 California Toxics Rule (40 CFR 131.38) per EPA (2000). CTR numeric criteria for protection of aquatic habitat.
Standards are applicable to all freshwater surface waters of the San Diego Region. All values rounded to two
significant figures. Discharge concentration standards established in the NPDES permit adopted by the RWQCB
may take into account potential mixing zone dilution credits allowed by the RWQCB.
32 CMC is the criteria maximum concentration, the highest concentration to which aquatic life can be exposed for
a short period of time without deleterious effect
33 CCC is the criteria continuous concentration, the highest concentration to which aquatic life can be exposed for
4 days without deleterious effect.
34 CMC and CCC water quality criteria for cadmium, chromium III, copper, lead, silver, and zinc are dependent
on receiving water hardness. (CTR limits become more stringent with lower hardness, and less stringent with
higher hardness concentrations.) The above values are based on a receiving water hardness of 100 mg/L.
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Table 6-5: California Toxics Rule Standards for the Protection of Human Health
Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)35
Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)32
Consumption
of Water36
Consumption
of Water plus
Organisms37
Consumption
of Water33
Consumption
of Water plus
Organisms34
TOXIC INORGANIC CONSTITUENTS ACID EXTRACTABLE COMPOUNDS
Antimony 4300 14 2-chlorophenol 400 120
Mercury 1300 NS 2,4-dichlorophenol 790 93
Copper 0.051 0.05 2,4-dimethylphenol 2300 540
Nickel 4600 610 2-methyl 4,6
dinitrophenol 765 13.4
Thallium 6.3 1.7 2,4-dinitrophenol 14,000 70
Cyanide 220,000 700 Pentachlorophenol 8.2 0.28
VOLATILE ORGANIC COMPOUNDS Phenol 4,600,000 21,000
Acrolein 780 320 2,4,6-trichlorophenol 6.5 2.1
Acrylonitrile 0.66 0.059 BASE NEUTRAL COMPOUNDS
Benzene 71 1.2 Acenaphthene 2700 1200
Bromoform 360 4.3 Anthracene 110,000 9600
Carbon
tetrachloride 4.4 0.25 Benzidene 0.00054 0.00012
Chlorobenzene 21,000 680 Benzo (a) anthracene 0.049 0.0044
Chlorodibromom
ethane 34 0.41 Benzo (a) pyrene 0.049 0.0044
Dichlorobromom
ethane 46 0.56 Benzo (b)
fluoranthene 0.049 0.0044
1,2-
dichloroethane 99 0.38 Benzo (k)
fluoranthene 0.049 0.0044
1,1-
dichloroethylene 3.2 0.057 Bis (2-chloroethoxy)
ether 1.4 0.031
1,2-
dichloropropane 39 0.52 Bis (2-
chloroisopropyl) ether 170,000 1400
1,3-
dichloropropene 1700 10 Bis (2-ethylhexyl)
phthalate 5.9 1.8
California Toxics Rule (40 CFR 131.38) per EPA (2000). All values rounded to two significant figures.
Standards are applicable to all freshwater surface waters of the San Diego Region.
35 California Toxics Rule (40 CFR 131.38) per EPA (2000). All values rounded to two significant figures. The above
standards are for ambient surface waters. Actual discharge concentration standards will be established in the
NPDES permit adopted by the RWQCB, and may take into account potential mixing zone dilution credits allowed
by the RWQCB.
36 CTR criteria for the consumption of water. Standard applicable to San Dieguito Reservoir.
37 CTR criteria for the consumption of water plus organisms. Standards applicable to potable water reservoirs that
allow fishing.
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Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)35
Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)32
Consumption
of Water36
Consumption
of Water plus
Organisms37
Consumption
of Water33
Consumption
of Water plus
Organisms34
Ethylbenzene 29,000 3100 Butyl benzyl
phthalate 5200 3000
Methyl bromide 4000 48 2-chloronaphthalene 4300 1700
Methylene
chloride 1600 4.7 Chrysene 0.049 0.0044
1,1,2,2-
tetrachloroethan
e
11 0.17 Dibenzo (a,h)
anthracene 0.049 0.0044
Tetrachloroethyl
ene 8.85 0.8 1,2-dichlorobenzene 17,000 2700
Toluene 200,000 6,800 1,3-dichlorobenzene 2600 400
1,2 trans-
dichloroethylene 140,000 700 1,4-dichlorobenzene 2600 400
1,1,2-
trichloroethane 42 0.60 3,3-
dichlorobenzidene 0.077 0.04
Trichloroethylen
e 81 2.7 Diethyl phthalate 120,000 23,000
Vinyl chloride 525 2.0 Dimethyl phthalate 2,900,000 313,000
CHLORINATED PESTICIDES Di-n-octyl phthalate 12,000 2700
Aldrin 0.00014 0.00013 2,4-dinitrotoluene 9.1 0.11
alpha BHC 0.013 0.0039 1,2-
diphenylhydrazine 0.54 0.04
beta BHC 0.046 0.014 Fluoranthene 370 300
gamma BHC
(Lindane) 0.063 0.019 Fluorene 14,000 1300
Chlordane 0.00059 0.00057 Hexachlorobenzene 0.00077 0.00075
4,4'-DDT 0.00059 0.00059 Hexachlorobutadiene 50 0.44
4,4'-DDD 0.00059 0.00059 Hexachlorocyclopent
adiene 17,000 240
4,4'-DDE 0.00084 0.00083 Hexachloroethane 8.9 1.9
Dieldrin 0.00014 0.00014 Ideno 1,2,3-cd
Pyrene 0.049 0.0044
alpha
Endosulfan 240 110 Isophorone 600 8.4
beta Endosulfan 240 110 Nitrobenzene 1900 17
Endosulfan
Sulfate 240 110 N-
nitrosodimethylamine 8.1 0.00069
Endrin 0.81 0.76 N-nitrosodi-n-
propylamine 1.4 0.005
Endrin Aldehyde 0.81 0.76 N-
nitrosodiphenylamine 16 5.0
Heptachlor 0.00021 0.00021 Pyrene 11,000 960
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Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)35
Constituent
Concentration (µg/l)
Standard Protection of
Human Health
(Monthly Average)32
Consumption
of Water36
Consumption
of Water plus
Organisms37
Consumption
of Water33
Consumption
of Water plus
Organisms34
Heptachlor
Epoxide 0.00011 0.00010 1,2,4-
trichlorobenzene 940 260
PCBs 0.00017 0.00017 DIOXANS AND DIFURANS
Toxaphene 0.00075 0.00073 2,3,7,8-TCDD 1.4E-08 1.3E-08
Footnotes:
1. NS indicates that no standard has been promulgated for the listed constituent and category.
6.3.4 Chlorine Policy
The CTR does not establish a standard for chlorine residual, but EPA has established national criteria for
chlorine residual concentrations to protect freshwater aquatic life.38 The SWRCB in 2006 proposed that the
EPA criteria be established as a statewide standard, but to date the draft chlorine residual standards have
not been implemented.39 The draft statewide chlorine standards currently being considered by the SWRCB
would require that dischargers reduce chlorine residual in discharges to receiving waters to as close to zero
as practicable. Pending approval of statewide standards for chlorine residual, the SWRCB has implemented
the EPA criteria maximum concentration (CMC) water quality criteria (see Table 6-6 below) in the current
statewide NPDES permit governing discharges to surface waters from drinking water systems.40 It is
anticipated that such a standard would also be applied to any surface water augmentation discharge to San
Dieguito Reservoir.
38 National water quality criteria for total chlorine published by EPA. (EPA, 2017)
39 See Policy for Implementation of Toxics Standards for Inland Surface Waters, Enclosed Bays, and Estuaries of
California. (SWRCB, 2006)
40 SWRCB General Order No. WQ 2014-0194-DWQ. (SWRCB, 2014)
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Table 6-6: Recommended Criteria for Chlorine for the Protection of Freshwater Aquatic Life
Parameter
National Recommended Water Quality Criteria41
(concentration in µg/L)
CMC42 CCC43
Chlorine Residual 1944 11
Raw Water Augmentation
Options G and H involve the potential use of purified recycled water for augmenting untreated water
supplies in Pipeline No. 5 of the SDCWA Second Aqueduct. Pipeline No. 5 provides supply to potable
water treatment plants and reservoirs operated by the Olivenhain Municipal Water District, Santa Fe
Irrigation District/San Dieguito Water District, City of San Diego, and Sweetwater Authority.
6.4.1 DDW Regulation
As noted in TM1, DDW has not developed uniform regulations governing the use of purified recycled water
for augmenting aqueduct supplies. It is probable, however, that such regulations (when developed) would
include additional treatment and monitoring requirements that would ensure the aqueduct discharge
scenario provides a degree of public health protection that is at least as protective as current water supply
operations and proposed DDW indirect potable reuse regulations.45
6.4.2 Probable RWQCB Regulation
Because aqueduct water from Pipeline No. 5 may be discharged to and stored in reservoirs, the RWQCB
would likely regulate the discharge of purified recycled water to the Second Aqueduct through issuance of
a NPDES permit that implements (1) applicable DDW requirements, and (2) surface water standards for
applicable terminal reservoirs. The same Basin Plan standards that are applicable to San Dieguito Reservoir
(see Table 6-3) are also applicable to each of the terminal reservoirs for Pipeline No. 5 (e.g., Olivenhain
Reservoir, Miramar Reservoir, San Vicente Reservoir, Sweetwater Reservoir).
Fishing is allowed in City of San Diego and Sweetwater Authority reservoirs that receive supply from
Pipeline No. 5. As a result, CTR human health standards for the consumption of water plus organisms (see
Table 6-5) would be applicable for any purified recycled water flow discharged to the Second Aqueduct.
In addition to Basin Plan and CTR standards, any NPDES permit governing aqueduct augmentation would,
of course, incorporate all applicable DDW regulations or requirements governing augmentation of Second
Aqueduct flows.
41 National recommended water quality criteria per EPA (2017) for the protection of aquatic freshwater life.
42 CMC is the criteria maximum concentration, the highest concentration to which aquatic life can be exposed for a
short period of time without deleterious effect.
43 CCC is the criteria continuous concentration, the highest concentration to which aquatic life can be exposed for
4 days without deleterious effect.
44 This 19 µg/l criterion has been established as a NPDES effluent concentration limit in the SWRCB general
NPDES permit (Order WQ 2014-0194-DWQ) that regulates discharges of potable water to surface waters.
(SWRCB, 2014)
45 See TM1 for a summary of issues and probable regulatory approaches associated with direct potable reuse.
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Brine Disposal
Each of the reuse options considered herein involve discharging waste brine to the EOO. Modification of
the EOO NPDES permit would be required to:
• address changes in facilities descriptions within the findings and Fact Sheet of the existing EMWPF
NPDES permit,46
• establish requirements for the discharge of waste brine to the EEO, and
• address changes in initial dilution created by the brine discharge.
NPDES permit effluent limitations in the EOO NPDES permit implement receiving water standards and
technology-based effluent standards that are established in the Ocean Plan, including receiving water
standards (Ocean Plan Table 1 standards) and technology-based standards (Ocean Plan Table 2 standards).47
6.5.1 Ocean Plan Technology-Based Standards
In part, Table 2 of the Ocean Plan includes technology-based standards for:
• Grease and oil (30-day average limit of 25 mg/L; daily maximum limit of 75 mg/L),
• Settleable solids (30-day average of 1.0 milliliters per liter; daily maximum of 1.5 ml/l),
• Turbidity (30-day average limit of 75 NTU; daily maximum limit of 225 NTU), and
• pH (pH to be maintained between 6.0 and 9.0 units at all time)
Ocean Plan Table 2 effluent standards apply to each individual discharge stream to the EOO, and the Ocean
Plan Table 2 standards would be imposed as NPDES effluent concentration standards for any brine
discharge to the EEO.
6.5.2 Ocean Plan Receiving Water Standards and Initial Dilution
Implications
Ocean Plan Table 1 receiving water standards apply to the combined discharge from the EOO. Ocean Plan
Table 1 standards apply to receiving waters beyond designated zones of initial dilution, and the Table 1
standards are to be achieved after completion of the initial dilution process. The Ocean Plan specifies that
NPDES effluent limits for regulated constituents within Table 1 be established on the basis of the following
equation: 𝐶𝑒= 𝐶𝑚+ 𝐶𝑚 ∙(𝐶𝑚− 𝐶𝑠)
Where Ce = NPDES effluent concentration standard for the Ocean Plan Table 1 constituent,
Co = Ocean Plan Table 1 receiving water concentration standard,
Dm = minimum probable initial dilution assigned by the RWQCB, and
Cs = ambient ocean water concentration.
The RWQCB currently assigns an initial dilution of 144:1 to the EOO on the basis of plume buoyancy and
dilution modeling completed by the SWRCB.48 Implementation of the reuse options considered herein will
increase the salinity of the EEO discharge, as EWPCF wastewater discharges to the EOO will be reduced
46 The EEO discharge (including discharges from the EWPCF, the Meadowlark Water Reclamation Plant, the
Shadowridge Water Reclamation Plant, and the Carlsbad Water Recycling Facility) is currently regulated by
RWQCB Order No. R9-2011-0009 (NPDES CA0107395). NPDES CA0107395 was set to expire on June 1,
2016, but the permit has been administratively continued by the RWQCB, and RWQCB action on the Encina
Wastewater Authority application for renewal of the NPDES permit is pending.
47 See Tables 1 and 2 of the Water Quality Control Plan, Ocean Waters of California (SWRCB, 2015).
48 See Section II.B of the Fact Sheet (Attachment F) to Order No. R9-2011-0019 (NPDES CA0107395).
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while the waste brine flows to the EOO will be increased. Dilution modeling will be required to assess how
the increased brine flows to the EOO will affect the assigned initial dilution, but it is possible that increased
brine contributions within the EOO would reduce the discharge plume buoyancy to the point where the
assigned initial may be significantly reduced.
Such a reduction in the assigned initial dilution should not affect EOO compliance with most constituents,
as the EOO currently complies with Ocean Plan-based NPDES requirements for individual toxic organic
and inorganic constituents by a comfortable margin. A reduction in the assigned initial dilution, however,
may potentially affect compliance with the Ocean Plan Table 1 receiving water standard for chronic
toxicity. Additional analysis will be required to (1) assess the impact of increased brine on EOO initial
dilution, and (2) evaluate how this reduction in initial dilution may affect compliance with the Ocean Plan
receiving water standard for chronic toxicity.
A brine discharge to the EOO under Options F, G or H would contain salinity concentrations well below
ambient ocean salinity levels. Such a brine discharge would not be subject to 2016 Ocean Plan Amendments
that address brine discharges from seawater desalination facilities.
An engineering report describing the proposed facilities and potable reuse operations will be required.
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7 Conceptual Cost Analysis
Cost Opinion Methodology
7.1.1 Cost Classification
An opinion of probable construction cost (OPCC) for each option was developed as a Class 4 opinion,
which is expected to be within a +50% to -30% accuracy range under a competitive bidding environment.49
Cost opinions were developed relying heavily on historical bid-based and cost-based methods to develop
raw construction costs. From the raw construction costs, several construction cost factors were applied to
develop opinions of total construction costs, followed by implementation factors to develop opinions of
total capital costs.
7.1.2 Construction Cost Allowances
From the raw construction cost subtotal, the construction cost factors listed below are applied to develop
an opinion of total construction costs.
• Construction contingency of 25% – The construction contingency is defined as unknown costs
due to lack of detailed engineering during the preliminary design phase that are estimated as a
percentage of defined project costs (i.e., raw construction cost subtotal). As the level of project
definition and understanding increases and the level of unknown decreases, the construction
contingency typically decreases. For this Study, a construction contingency of 25% was applied to
the raw construction cost estimates. This is also intended to include Owner’s reserve for change
orders, which may be a result of the Owner’s direction to implement additional work, differing
field conditions that require additional work, or an error in the project contract documents.
• Tax on Materials = 8%, applied to 50% of construction subtotal – A Class 4 estimate uses
installed unit cost metrics that include both raw materials and installation (i.e., labor and equipment)
costs. Therefore, tax on materials was estimated as 8.0% (local tax) and applied to 50% of the
construction cost subtotal.
• Shipping rate = 15% applied to 40% of the construction cost subtotal – A Class 4 estimate uses
installed unit cost metrics that include both raw materials and installation (i.e., labor and equipment)
costs. Therefore, shipping costs for equipment delivery were estimated as 15% and applied to 40%
of the construction cost subtotal.
• Overhead and Profit = 15% – Overhead and profit (O&P) represents the general contractor’s
operating costs and estimated profit levels. The O&P factor typically varies between 10% and 25%,
depending on the size of the project and market conditions, with larger projects typically having
lower O&P factors. An O&P factor of 15% was applied to the construction cost subtotal.
At this conceptual feasibility study stage, costs not considered include but are not limited to additional
planning, administration, legal, and property acquisition.
7.1.3 Implementation Cost Allowances
To generate the opinions of total capital costs for the project, implementation costs such as design,
environmental review, construction management, engineering services during construction, and other
administrative costs associated with the project are included. Implementation costs are typically estimated
49 As defined by the Association for the Advancement of Cost Engineering International (AACE International).
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as a percentage of total construction cost, including all allowances described in Section 7.1.2 above. The
implementation allowances used are summarized below.
• Environmental Documentation and Permits = 5% – Environmental documentation and permits
involves producing environmental studies and acquiring any permits necessary to construct a
project. A factor of 5% was applied to the total construction cost for environmental documentation
and permits.
• Engineering Services = 10% – Engineering services include field investigations (e.g., surveys,
geotechnical reports, hazard materials investigations), preliminary and final design, contract
document development (i.e. plans and specifications), preparation of detailed cost estimates, and
project scheduling. An engineering services factor of 10% was applied to the total construction
cost.
• Construction Management = 5% – Costs for construction management, including inspection, can
vary greatly with project size and complexity and whether the Owner performs this work with in-
house staff or through a consultant. A construction management factor of 5% was applied to the
total construction cost.
• Engineering Services During Construction = 5% – Engineering services during construction
(ESDC) typically include submittal and request for information (RFI) reviews, design
clarifications, and startup support services. An ESDC factor of 5% was applied to the total
construction cost.
7.1.4 Capital Financing Assumptions
Financing assumptions used to annualize capital costs are:
• Capital costs would be 100% financed
• Annual interest rate: 2.0%
• Term of Financing: 30 years
• Discount Rate: 0%
Over the last 10 years, the General Obligation (GO) Bond interest rate has varied from 1.7% to 3.0% and
may increase. Actual project financing will vary based on the current market conditions and the type of
loan secured. For the purposes of the analysis in this TM, no consideration was given to any grants or
special loans that may be awarded to EWA for this Project.
7.1.5 Operations and Maintenance (O&M) Costs
Operations and maintenance (O&M) requirements were derived from experience on similar projects and
standard engineering methods. The three components used to develop annual O&M costs were:
• Labor – Labor costs associated with new treatment and conveyance facilities O&M are calculated
on an hourly basis, with 2080 hours per year assumed to be one full-time equivalent (FTE). The
required labor hours are estimated based on experience with prior projects and other current
systems in operation. The average hourly cost of an O&M personnel, including overhead, is
estimated to be $75.
• Power – The unit cost of electricity used is $0.15/kWh. Any offsets available from power produced
at the EWPCF were not considered.
• Equipment Rehabilitation/Replacement and Consumables - Consumables are major
component of operation expenditures and include resources that are intended and expected to be
used up relatively quickly. Example of consumables include chemicals, gaskets, and potable water.
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Where specific consumable line items could not be quantified, consumable costs were estimated as
1% of the raw construction cost.
Costs by Option
This section presents the cost opinions for each of the three main Options evaluated. The capital costs are
summarized under three categories:
• EWPCF Secondary Improvements
• AWTF
• Conveyance
The annual O&M costs are summarized under the following categories:
• Power for treatment (including both the incremental power requirements at the EWPCF and the
requirements for the AWTF)
• Power for conveyance (pumping)
• Other O&M costs: this includes equipment rehabilitation/replacement and consumables (across all
improved and new facilities), and labor for the AWTF and the conveyance system (pipeline
maintenance)
The total capital costs are annualized using the financing assumptions presented in Section 7.1.4 above and
combined with the O&M costs to develop a cost of water per acre-foot produced. An overview of the
OPCCs and costs of water for the three Options are provided in Figures 7-1 and 7-2; cost summary tables
are provided in Tables 7-1 through 7-5. Detailed cost tables for the components of each option are provided
in Appendix A.
Figure 7-1: Capital Cost Summary for Options F, G, and H.
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Figure 7-2: Cost of Water Summary for Options F, G, and H.
Table 7-1: Cost Summary for Option F.
Option F: Carlsbad Desalination Plant Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Water Treatment Facility
(FAT+O3/BAF+WTP) $283,900,000 at 20.5 mgd influent rate
Conveyance - North $142,800,000 at 20.5 mgd influent rate
Total Capital Cost $515,700,000
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $5,671,000 24/7/365 operations
Power - Conveyance $15,853,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $6,309,000 All new facilities (incl. EWCPF)
Labor $1,270,000 AWTF + Conveyance
Total Annual O&M Cost $29,110,000
Cost of Water
Annualized Capital Cost $23,026,000 2.0% rate, 30-yr term
Total Annual Cost $52,136,000 for first 30 years
Annual Yield 17,700 acre-feet
Unit Cost - Capital $1,310 per acre-foot
Unit Cost - O&M $1,650 per acre-foot
Unit Cost of Water $2,960 per acre-foot
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Table 7-2: Cost Summary for Option G.
Option G: San Dieguito Groundwater Basin and
SDCWA Second Aqueduct (All Phases) Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Treatment (FAT + O3/BAF) $234,400,000 at 20.5 mgd influent rate
Conveyance - South $287,400,000 at 20.5 mgd influent rate
Total Capital Cost $610,800,000
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $5,403,000 24/7/365 operations
Power - Conveyance $15,501,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $6,580,000 All new facilities (incl. EWCPF)
Labor $1,221,000 AWTF + Conveyance
Total Annual O&M Cost $28,705,000
Cost of Water
Annualized Capital Cost $27,273,000 2.0% rate, 30-yr term
Total Annual Cost $55,978,000 for first 30 years
Annual Yield 17,800 acre-feet
Unit Cost - Capital $1,540 per acre-foot
Unit Cost - O&M $1,620 per acre-foot
Unit Cost of Water $3,160 per acre-foot
Table 7-3: Cost Summary for Option H.
Option H1: SDCWA Second Aqueduct and San
Marcos Groundwater Basin Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Treatment (FAT + O3/BAF) $234,400,000 at 20.5 mgd influent rate
Conveyance - East $180,400,000 at 20.5 mgd influent rate
Total Capital Cost $503,800,000
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $5,403,000 24/7/365 operations
Power - Conveyance $13,387,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $5,724,000 All new facilities (incl. EWCPF)
Labor $1,144,000 AWTF + Conveyance
Total Annual O&M Cost $25,658,000
Cost of Water
Annualized Capital Cost $22,495,000 2.0% rate, 30-yr term
Total Annual Cost $48,153,000 for first 30 years
Annual Yield 17,800 acre-feet
Unit Cost - Capital $1,270 per acre-foot
Unit Cost - O&M $1,450 per acre-foot
Unit Cost of Water $2,720 per acre-foot
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7.2.1 Comparison to Projected Cost of Water for Other Water Sources
To provide context for the cost of water developed for this Study’s Options, information on the costs of
other sources of water available in the region and in the State of California is provided below (California
Public Utilities Commission [CPUC] 2016):
• SDCWA treated water costs are expected to reach $3,880/af by 2040.
• Conservation programs can provide substantial incentives for water savings, such as the CPUC
unaccounted for water (UFW) incentive mechanism that provides $2,019/af.
• Planning for other recent potable reuse projects in California, such as San Diego Pure Water and
Monterey Pure Water, have projected costs in the $2,000 to $5,000 per af range.
• Desalinated product water provided to SDCWA member agencies cost up to $2,367/af in 2016.
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8 Conclusions
In evaluating the relative merits of the three options presented in this TM, the following criteria were used:
• Cost of water
• Likely timeframe for regulatory acceptance and project implementation
• Complexity of operations and compliance
• Expected demand and stakeholder support
Key information for each of these criteria is presented in Table 8-1, based on each option at the full projected
2040 flows for the EWPCF (i.e., 20.5 mgd influent to the AWTF).
Table 8-1: Summary of Key Considerations for EWA’s Potable Reuse Options.
Option F
Carlsbad Desal. Plant
Option G
San Dieguito + 2nd Aqueduct
Option H
2nd Aqueduct + San Marcos
Cost of Water
(at 20.5 mgd
influent)
$2,960/af $3,160/af $2,720/af
Time to
Implement 15-20+ years 10-15 years 10-15 years
Regulatory
Considerations Timeframe uncertain Legislation pending Legislation pending
Complexity of
Operations &
Compliance
AWTF “c”
Blending & Pumping at
CDP
AWTF “b”
Up to three forms of potable
reuse (reservoir +
groundwater + raw water)
AWTF “b”
Up to two forms of potable
reuse (raw water +
groundwater)
Key
Stakeholders
SDCWA
Poseidon
SEJPA, SDWD, SFID,
OMWD, SDCWA
SDCWA
Vallecitos WD
Based on these criteria, it is recommended that Option H be carried forward for further phasing analysis
under TM4 and funding analysis under TM5. A potential implementation schedule for the various
components of Option H (i.e., EWPCF improvements, AWTF, and conveyance/receptor integration
infrastructure) will also be provided under TM4.
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Date: 1/25/2018Project Number: 0305-059Prepared By: Trussell Technologies, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostPrimary Effluent Flow Equalization7,900,000$ Flow EQ Basin 2EA$2,700,0005,400,000$ Primary Effluent Pipe1LS$1,500,0001,500,000$ Pump Station/ Modulating Valve1LS$1,000,0001,000,000$ ItemDescriptionSize Units Quantity Unit Unit CostTotal CostAeration Basins (4)8,620,000$ Baffling12EA$50,000600,000$ Blower Upgrades1LS$2,800,0002,800,000$ Anoxic Zone Mixers1LS$960,000960,000$ Fine Bubble Aeration Equipment1LS$2,000,0002,000,000$ Internal Mixed Liquor Pumps1LS$460,000460,000$ Piping/Basin Modifications for IMLR1LS$100,000100,000$ Scum and Foam Control1LS$500,000500,000$ Demo of Existing Aeration Equipment1LS$100,000100,000$ Air Piping/Valves/ DO Control1LS$1,100,0001,100,000$ ItemDescriptionSize Units Quantity Unit Unit CostTotal Cost7,000,000$ Circular Clarifier, New2EA$1,500,0003,000,000$ Retaining Wall1LS$1,000,0001,000,000$ Equipping Existing Clarifier No. 71LS$500,000500,000$ Secondary Effluent Pump Station1LS$1,500,0001,500,000$ Piping/Valving1LS$1,000,0001,000,000$ ItemDescriptionSize Units Quantity Unit Unit CostTotal CostTertiary Filters19,300,000$ Gravity Filter Housing and Underdrain6EA$1,333,3338,000,000$ Piping/Valving1LS$5,000,0005,000,000$ Filter Media1LS$1,200,0001,200,000$ Backwash Pump Station1LS$2,000,0002,000,000$ Air Scour Wash1LS$2,800,0002,800,000$ Waste Wash Water Equalization Tank1LS$300,000300,000$ Project: Encina Water Reuse Feasibility StudyElement: EWPCF ImprovementsSecondary ClarifiersPage 1 Sept. 27, 2022 Item #10 Page 212 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Trussell Technologies, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)Project: Encina Water Reuse Feasibility StudyElement: EWPCF Improvements2,736,000$ Installation of Aeration Basin and Clarifier Equipment 1 LS $2,736,000 2,736,000$ Cost Summary SubtotalPrimary Effluent Flow Equalization7,900,000$ Aeration Basins (4)8,620,000$ Secondary Clarifiers7,000,000$ Tertiary Filters19,300,000$ Equipment Installation2,736,000$ Raw Construction Subtotal45,556,000$ Construction Contingency 25%11,389,000$ Construction Cost Subtotal56,945,000$ Tax on Materials 8.00%2,278,000$ Shipping 15%3,417,000$ General Contractor Overhead and Profit 15%8,542,000$ Estimated Total Construction Cost71,182,000$ Environmental Documentation and Permits 5%3,560,000$ Engineering Services (Design) 10%7,119,000$ Construction Management 5%3,560,000$ Engineering Services During Construction 5%3,560,000$ Total Capital Cost89,000,000$ SubtotalPowerAeration Blowers 1,143 hp 13,420,000 kWh 0.15$ 2,013,000$ IMLR Pumps 69 hp 810,667 kWh 0.15$ 122,000$ Anoxic Zone Mixers 27 hp 313,333 kWh 0.15$ 47,000$ EquipmentEquipment Rehabilitation and Replacement71,500$ Total Annual O&M Cost2,254,000$ O&M CostsEWPCF ImprovementsEquipment InstallationPage 2 Sept. 27, 2022 Item #10 Page 213 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Carollo Engineers, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostTreatment Unit Operations and Buildings57,372,000$ Ultrafiltration System 1 LS $9,225,000 9,225,000$ Reverse Osmosis System 1 LS $10,978,000 10,978,000$ Ultraviolet/ Advanced Oxidation Process System 1 LS $2,050,000 2,050,000$ Product Water Tank 1 LS $1,047,000 1,047,000$ Carbon Dioxide System 1 LS $854,000 854,000$ Lime System1 LS $1,719,000 1,719,000$ Chemical System1 LS $2,543,000 2,543,000$ Feed Pipeline + Pump Station 1 LS $1,527,000 1,527,000$ Brine Pipeline + Pump Station 1 LS $1,561,000 1,561,000$ Yard Piping1 LS $3,608,000 3,608,000$ Process Building 39,600 SF $350 13,860,000$ Admin. and Maintenance Building 14,000 SF $350 4,900,000$ Electrical Building and Electrical Rooms 14,000 SF $250 3,500,000$ ItemDescription Size Units Quantity Unit Unit Cost Total CostFactored Costs26,339,000$ Site work 5% 1 LS $2,868,600 $2,869,000Electrical & IC 30% 1 LS $14,691,600 $14,692,000Mechanical 25% 1 LS $8,778,000 $8,778,000Cost Summary SubtotalTreatment Unit Operations and Buildings57,372,000$ Factored Costs26,339,000$ Raw Construction Subtotal83,711,000$ Construction Contingency 25%20,927,750$ Construction Cost Subtotal104,639,000$ Tax on Materials 8.00%4,186,000$ Shipping 15%6,279,000$ General Contractor Overhead and Profit 15%15,696,000$ Estimated Total Construction Cost130,800,000$ Environmental Documentation and Permits 5%6,540,000$ Engineering Services (Design) 10%13,080,000$ Construction Management 5%6,540,000$ Engineering Services During Construction 5%6,540,000$ Total Capital Cost163,500,000$ SubtotalPowerElement: 16 mgd AWTF "a" (FAT)TreatmentO&M CostsProject: Encina Water Reuse Feasibility StudyPage 3 Sept. 27, 2022 Item #10 Page 214 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Carollo Engineers, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)Element: 16 mgd AWTF "a" (FAT)Project: Encina Water Reuse Feasibility StudyUF152 hp 1,782,353 kWh0.15$ 267,353$ RO864 hp 10,141,176 kWh0.15$ 1,521,176$ UV/AOP100 hp 1,170,588 kWh0.15$ 175,588$ Product Water Conditioning12 hp135,294 kWh0.15$ 20,294$ Chemical Dosing Systems5 hp52,941 kWh0.15$ 7,941$ Building HVAC Systems115 hp 1,347,059 kWh0.15$ 202,059$ Feed Pump Station85 hp 1,000,000 kWh0.15$ 150,000$ Brine Pump Station105 hp 1,235,294 kWh0.15$ 185,294$ Misc. Facility Power10 kW87,600 kWh0.15$ 14,000$ ChemicalsUF Pretreatment and Cleaning496,000$ RO Pretreatment and Cleaning565,000$ UF93,000$ UV/AOP98,000$ RO139,000$ UV/AOP43,000$ Product Water Conditioning3,000$ Chemical Dosing Systems22,000$ Electrical Equipment112,000$ Product Water Conditioning1,047,000$ Pipeline Chlorination73,000$ Replacement of ConsumablesMF Modules296,000$ RO Cartidge Filters and Membrane Elements536,000$ UV Lamps and Ballasts77,000$ MaintenanceSite Security69,000$ Landscaping23,000$ Janitorial Services69,000$ Hazardous Waste Clean-up6,000$ LaborO&M Labor624,000$ Total O&M Cost7,000,000$ Page 4 Sept. 27, 2022 Item #10 Page 215 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Carollo Engineers, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostO3/BAF+FAT80,418,000$ LOX Feed Facility1 LS $1,429,000 1,429,000$ Ozone Generation Facility 1 LS $5,504,000 5,504,000$ Ozone Contactors Facility 1 LS $4,943,000 4,943,000$ Biologically Activated Carbon System 1 LS $8,265,000 8,265,000$ Ultrafiltration System 1 LS $9,225,000 9,225,000$ Reverse Osmosis System 1 LS $10,978,000 10,978,000$ Ultraviolet/ Advanced Oxidation Process System 1 LS $2,050,000 2,050,000$ Product Water Tank1 LS $1,047,000 1,047,000$ Carbon Dioxide System 1 LS $854,000 854,000$ Lime System1 LS $1,719,000 1,719,000$ Chemical System1 LS $2,528,000 2,528,000$ Feed Pipeline + Pump Station 1 LS $1,527,000 1,527,000$ Brine Pipeline + Pump Station 1 LS $1,561,000 1,561,000$ Yard Piping1 LS $3,588,000 3,588,000$ Process Building48,000 SF $350 16,800,000$ Admin. and Maintenance Building 14,000 SF $350 4,900,000$ Electrical Building 14,000 SF $250 3,500,000$ ItemDescription Size Units Quantity Unit Unit Cost Total CostFactored Costs39,431,000$ Site work 5% 1 LS $4,020,900 4,021,000$ Electrical & IC 30% 1 LS $21,605,400 21,605,000$ Mechanical 25% 1 LS $13,804,500 13,805,000$ Cost Summary SubtotalO3/BAF+FAT81,000,000$ Factored Costs39,431,000$ Raw Construction Subtotal120,000,000$ Construction Contingency 25%30,000,000$ Construction Cost Subtotal150,000,000$ Tax on Materials 8.00%6,000,000$ Shipping 15%9,000,000$ General Contractor Overhead and Profit 15%22,500,000$ Estimated Total Construction Cost187,500,000$ Environmental Documentation and Permits 5%9,375,000$ Engineering Services (Design) 10%18,750,000$ Construction Management 5%9,375,000$ Engineering Services During Construction 5%9,375,000$ Total Capital Cost234,400,000$ Element: 16 mgd AWTF "b" (FAT + O3/BAF)TreatmentProject: Encina Water Reuse Feasibility StudyPage 5 Sept. 27, 2022 Item #10 Page 216 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Carollo Engineers, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)Element: 16 mgd AWTF "b" (FAT + O3/BAF)Project: Encina Water Reuse Feasibility StudySubtotalPower Ozone 381 hp 4,476,471 kWh 0.15$ 671,471$ BAC 4 hp 41,176 kWh 0.15$ 6,176$ MF 152 hp 1,782,353 kWh 0.15$ 267,353$ RO 864 hp 10,141,176 kWh 0.15$ 1,521,176$ UV/AOP 100 hp 1,170,588 kWh 0.15$ 175,588$ Product Water Conditioning 12 hp 135,294 kWh 0.15$ 20,294$ Chemical Dosing Systems 5 hp 52,941 kWh 0.15$ 7,941$ Building HVAC Systems 115 hp 1,347,059 kWh 0.15$ 202,059$ Feed Pump Station 85 hp 1,000,000 kWh 0.15$ 150,000$ Brine Pump Station 105 hp 1,235,294 kWh 0.15$ 185,294$ Misc. Facility Power 10 kW 87,600 kWh 0.15$ 14,000$ Equipment Rehab/Replacement BAF Filter Media Replacement134,000$ MF Modules296,000$ RO Cartidge Filters and Membrane Elements536,000$ UV Lamps and Ballasts77,000$ Ozone77,000$ ChemicalOzone364,000$ MF Pretreatment and Cleaning496,000$ RO Pretreatment and Cleaning565,000$ UV/AOP98,000$ Product Water Conditioning1,047,000$ Pipeline Chlorination73,000$ BAF34,000$ MF93,000$ RO139,000$ UV/AOP43,000$ Product Water Conditioning3,000$ Chemical Dosing Systems22,000$ Electrical Equipment112,000$ Special ContractsSite Security69,000$ Landscaping23,000$ Janitorial Services69,000$ Hazardous Waste Clean-up6,000$ Labor936,000$ Total O&M Cost8,600,000$ O&M CostsPage 6 Sept. 27, 2022 Item #10 Page 217 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: Carollo Engineers, Inc.Reviewed by: RMC / Woodard & CurranCost Opinion Type: Planning (Class IV)ItemDescriptionSize Units Quantity Unit Unit CostTotal CostO3/BAF+FAT+ WTP96,382,000$ LOX Feed Facility1LS$1,429,0001,429,000$ Ozone Generation Facility1LS$5,504,0005,504,000$ Ozone Contactors Facility1LS$4,943,0004,943,000$ Biologically Activated Carbon System1LS$8,265,0008,265,000$ Ultrafiltration System1LS$9,225,0009,225,000$ Reverse Osmosis System1LS$10,978,00010,978,000$ Ultraviolet/ Advanced Oxidation Process System1LS$2,050,0002,050,000$ Engineered Storage Buffer1LS$1,625,0001,625,000$ Chlorine Dosing System 1LS$493,000493,000$ Aqua Ammonia Dosing System1LS$311,000311,000$ Ultrafiltration System1LS$13,255,00013,255,000$ Product Water Tank1LS$1,047,0001,047,000$ Carbon Dioxide System1LS$854,000854,000$ Lime System1LS$1,719,0001,719,000$ Chemical System1LS$2,528,0002,528,000$ Feed Pipeline + Pump Station1LS$1,527,0001,527,000$ Brine Pipeline + Pump Station1LS$1,561,0001,561,000$ Yard Piping1LS$3,588,0003,588,000$ Process Building48,800 SF$35017,080,000$ Admin. and Maintenance Building14,000 SF$3504,900,000$ Electrical Building14,000 SF$2503,500,000$ ItemDescriptionSize Units Quantity Unit Unit CostTotal CostFactored Costs48,940,000$ Site work5%1LS$4,819,1004,819,000$ Electrical & IC30%1LS$26,394,60026,395,000$ Mechanical25%1LS$17,725,50017,726,000$ Cost Summary SubtotalO3/BAF+FAT+ WTP96,382,000$ Factored Costs48,940,000$ Raw Construction Subtotal145,322,000$ Construction Contingency 25%36,330,500$ Construction Cost Subtotal181,653,000$ Tax on Materials 8.00%7,267,000$ Shipping 15%10,900,000$ General Contractor Overhead and Profit 15%27,248,000$ Estimated Total Construction Cost227,068,000$ Environmental Documentation and Permits 5%11,354,000$ Engineering Services (Design) 10%22,707,000$ Construction Management 5%11,354,000$ Engineering Services During Construction 5%11,354,000$ Total Capital Cost283,900,000$ Element: 15.8 mgd AWTF "c" (FAT+O3/BAF + WTP)TreatmentProject: Encina Water Reuse Feasibility StudyPage 7 Sept. 27, 2022 Item #10 Page 218 of 279
SubtotalPower Ozone 381 hp 4,476,471 kWh 0.15$ 671,471$ BAC 4 hp 41,176 kWh 0.15$ 6,176$ UF (FAT) 152 hp 1,782,353 kWh 0.15$ 267,353$ RO 864 hp 10,141,176 kWh 0.15$ 1,521,176$ UV/AOP 100 hp 1,170,588 kWh 0.15$ 175,588$ UF (WTP) 152 hp 1,782,353 kWh 0.15$ 267,353$ Product Water Conditioning 12 hp 135,294 kWh 0.15$ 20,294$ Chemical Dosing Systems 5 hp 52,941 kWh 0.15$ 7,941$ Building HVAC Systems 115 hp 1,347,059 kWh 0.15$ 202,059$ Feed Pump Station 85 hp 1,000,000 kWh 0.15$ 150,000$ Brine Pump Station 105 hp 1,235,294 kWh 0.15$ 185,294$ Misc. Facility Power 10 kW 87,600 kWh 0.15$ 14,000$ ChemicalOzone364,000$ MF Pretreatment and Cleaning496,000$ RO Pretreatment and Cleaning565,000$ UV/AOP98,000$ UF Pretreatment and Cleaning496,000$ Product Water Conditioning1,047,000$ Pipeline Chlorination73,000$ Equipment Rehab/Replacement BAF Filter Media Replacement134,000$ UF Modules (FAT)296,000$ RO Cartidge Filtera and Membrane Elements536,000$ UV Lamps and Ballasts77,000$ UF Modules (WTP)296,000$ Ozone77,000$ BAF34,000$ UF (FAT)93,000$ RO139,000$ UV/AOP43,000$ UF (WTP)93,000$ Product Water Conditioning3,000$ Chemical Dosing Systems22,000$ Electrical Equipment112,000$ Special ContractsSite Security69,000$ Landscaping23,000$ Janitorial Services69,000$ Hazardous Waste Clean-up6,000$ Labor1,092,000$ Total O&M Cost9,900,000$ O&M CostsPage 8 Sept. 27, 2022 Item #10 Page 219 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: K. EricksonReviewed by: N. ChaseCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostOption F: Carlsbad Desalination Plant73,100,000$ Pump Station1,000 hp $6,500 6,500,000$ Segment 1 Pipe 30 inch 15.8 mgd 13,200 LF $750 9,900,000$ Trenchless Freeway 2 500 LF $2,000 2,000,000$ Trenchless Palomar Airport Road 1 500 LF $2,000 1,000,000$ Trenchless Railroad 1 200 LF $2,000 400,000$ Discharge Appurt at Desal plant wet well 1 LS $250,000 250,000$ New Clearwell with Baffling at Desal Plant 350,000 gallon $3.00 1,050,000$ Pump Station at Desal Plant wet well 8,000 hp $6,500 52,000,000$ Cost Summary SubtotalOption F: Carlsbad Desalination Plant73,100,000$ Raw Construction Subtotal73,100,000$ Construction Contingency 25%18,275,000$ Construction Cost Subtotal91,375,000$ Tax on Materials 8.00%3,655,000$ Shipping 15%5,483,000$ General Contractor Overhead and Profit 15%13,707,000$ Opinion of Total Construction Cost114,220,000$ Environmental Documentation and Permits 5%5,711,000$ Engineering Services (Design) 10%11,422,000$ Construction Management 5%5,711,000$ Engineering Services During Construction 5%5,711,000$ Total Capital Cost142,800,000$ SubtotalPumping Power 9,000 hp105,683,646 kWh 0.15$ 15,853,000$ Pipeline O&M Labor 1 hr/yr/100 LF14,400 LF 75.00$ 11,000$ Conveyance Infrastructure Rehabilitation/Replacement 1%1,143,000$ Total O&M Cost17,007,000$ Element: Option F Conveyance (North)ConveyanceO&M CostsProject: Encina Water Reuse Feasibility StudyPage 9 Sept. 27, 2022 Item #10 Page 220 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: K. EricksonReviewed by: N. ChaseCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostOption G: San Dieguito Groundwater Basin and Aqueduct #2 (All Phases)147,112,000$ Pump Station EWA800 hp $6,500 5,200,000$ Segment 1 Pipe 30 inches 43,824 LF $750 32,868,000$ Trenchless Lagoon Crossing 3,600 LF $2,000 7,200,000$ Pump Station SEJPA PS 3,200 hp $6,500 20,800,000$ Segment 2 Pipe 20 inches 33,264 LF $500 16,632,000$ Trenchless Freeway500 LF $2,000 1,000,000$ Segment 3 Pipe Existing 24 inches 27,456 LF $0 -$ Segment 3 Pipe Slip Line 24 inches 23,250 LF $120 2,790,000$ Segment 3 Pipe Open Cut 24 inches 2,200 LF $180 396,000$ Discharge Structure to San Dieguito Res. (incl. dechlorination)3.1 mgd 1 LS $2,000,000 2,000,000$ Pump Station to Badger WTP 4,800 hp $6,500 31,200,000$ Segment 4 Pipe 30 inches 11,088 LF $750 8,316,000$ Segment 5 Pipe 12 inches 12,144 LF $300 3,643,000$ GW Desalter (ext. wells, desal, brine, product conveyance) 1.0 mgd 1 MG -- -$ GWR Injection Wells in San Dieguito Basin 2.0 mgd 2 MG $1,000,000 2,000,000$ GW Desalter expansion - Extraction Wells 2.0 mgd 2 MG $1,033,333 2,067,000$ GW Desalter expansion - pre+RO treatment 2.0 mgd 2 MG $5,500,000 11,000,000$ GW Desalter expansion - Brine Disposal -- -- -$ GW Desalter expansion - Product Water Conveyance -- -- -$ Element: Option G Conveyance (South)Project: Encina Water Reuse Feasibility StudyPage 10 Sept. 27, 2022 Item #10 Page 221 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: K. EricksonReviewed by: N. ChaseCost Opinion Type: Planning (Class IV)Element: Option G Conveyance (South)Project: Encina Water Reuse Feasibility StudyCost Summary ConveyanceSubtotalOption G: San Dieguito Groundwater Basin and Aqueduct #2 (All Phases)147,112,000$ Raw Construction Subtotal147,112,000$ Construction Contingency 25%36,778,000$ Construction Cost Subtotal183,890,000$ Tax on Materials 8.00%7,356,000$ Shipping 15%11,034,000$ General Contractor Overhead and Profit 15%27,584,000$ Estimated Total Construction Cost229,864,000$ Environmental Documentation and Permits 5%11,494,000$ Engineering Services (Design) 10%22,987,000$ Construction Management 5%11,494,000$ Engineering Services During Construction 5%11,494,000$ Total Capital Cost287,400,000$ SubtotalPumping Power 8,800 hp 103,335,121 kWh 0.15$ 15,501,000$ Treatment Power 400 hp4,697,051 kWh0.17$ 799,000$ Pipeline O&M Labor1 hr/yr/100 LF 157,326 LF75.00$ 118,000$ Conveyance Infrastructure Rehabilitation/Replacement1%2,299,000$ Total O&M Cost18,717,000$ O&M Costs (All Phases)Page 11 Sept. 27, 2022 Item #10 Page 222 of 279
Date: 1/25/2018Project Number: 0305-059Prepared By: K. EricksonReviewed by: N. ChaseCost Opinion Type: Planning (Class IV)ItemDescription Size Units Quantity Unit Unit Cost Total CostOption H1: SDCWA Second Aqueduct and San Marcos Groundwater Basin92,343,000$ Pump Station EWA5,600 hp $6,500 36,400,000$ Segment 1 Pipe 30 inches 39,600 LF $750 29,700,000$ Trenchless Freeway500 LF $2,000 1,000,000$ Pump Station to SDCWA turnout 2,000 hp $6,500 13,000,000$ Discharge Appurt at SDCWA turnout 1 LS $250,000 250,000$ Segment 2 Pipe Existing 12 inches 14,256 LF $0 -$ Segment 2 Pipe Slip Line 12 inches 14,256 LF $100 1,426,000$ GWR Injection Wells in San Marcos Basin 2 MG $1,000,000 2,000,000$ GW Desalter expansion - Extraction Wells 2 MG $1,033,333 2,067,000$ GW Desalter expansion - wellhead treatment 2 MG $3,250,000 6,500,000$ GW Desalter expansion - Product Water Conveyance -- -- -$ Cost Summary SubtotalOption H1: SDCWA Second Aqueduct and San Marcos Groundwater Basin92,343,000$ Raw Construction Subtotal92,343,000$ Construction Contingency 25%23,085,750$ Construction Cost Subtotal115,429,000$ Tax on Materials 8.00%4,618,000$ Shipping 15%6,926,000$ General Contractor Overhead and Profit 15%17,315,000$ Estimated Total Construction Cost144,288,000$ Environmental Documentation and Permits 5%7,215,000$ Engineering Services (Design) 10%14,429,000$ Construction Management 5%7,215,000$ Engineering Services During Construction 5%7,215,000$ Total Capital Cost180,400,000$ SubtotalPumping Power 7,600 hp89,243,968 kWh 0.15$ 13,387,000$ Treatment Power 150 hp1,761,394 kWh0.15$ 265,000$ Pipeline O&M Labor1 hr/yr/100 LF 54,356 LF75.00$ 41,000$ Conveyance Infrastructure Rehabilitation/Replacement1%1,443,000$ Total O&M Cost15,136,000$ Element: Option H Conveyance (East)ConveyanceO&M CostsProject: Encina Water Reuse Feasibility StudyPage 12 Sept. 27, 2022 Item #10 Page 223 of 279
EWA Water Reuse Feasibility Study
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July 2018 1
Technical Memorandum No. 4
EWA Water Reuse Feasibility Study
Subject: Phasing of Preferred Project
Prepared For: Encina Wastewater Authority
Prepared by: Nathan Chase, P.E., Martha de Maria y Campos | Woodard & Curran
Reviewed by: Scott Goldman, P.E. | Woodard & Curran
Date: July 2018 (Draft: July 2018)
Table of Contents
1 Introduction ........................................................................................................................................... 3
Feasibility Study Background ....................................................................................................... 3
Objectives ..................................................................................................................................... 3
2 Initial Phase for Secondary and Advanced Treatment Facilities .......................................................... 4
EWPCF Improvements ................................................................................................................. 4
AWTF Pilot/Demonstration Study ................................................................................................ 5
3 Evaluation of AWTF Size and Phased Expansion ................................................................................ 7
EWA Facilities Footprint Analysis ............................................................................................... 7
Conveyance and SDCWA System Integration ............................................................................. 7
Sensitivity Analysis of Conceptual Costs ..................................................................................... 9
Comparison of EWA Water Costs to Regional Alternatives ...................................................... 11
4 Implementation Plan and Schedule ..................................................................................................... 13
Regulatory Activities .................................................................................................................. 13
Environmental Documentation ................................................................................................... 15
Source Water Analysis ................................................................................................................ 15
Engineering, Design, and Construction Activities ...................................................................... 15
Funding Applications .................................................................................................................. 16
Stakeholder/Public Outreach ....................................................................................................... 17
Implementation Schedule ............................................................................................................ 18
5 Conclusions and Next Steps ................................................................................................................ 19
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List of Figures
Figure 2-1: Proposed AWTF Treatment Train for RWA. ............................................................................. 5
Figure 3-1: Project Treatment Facilities Footprint Layout (16 mgd RWA) ................................................. 8
Figure 3-2: Capital Cost Summary for Option H Phasing .......................................................................... 10
Figure 3-3: Cost of Water Summary for Option H Phasing ........................................................................ 11
Figure 3-4: Comparative Cost of Water for EWA’s Option H and SDCWA Projected Costs ................... 12
Figure 4-1: Regulatory Approval Process Steps. ........................................................................................ 13
Figure 4-2: Implementation Schedule for EWA’s Potable Reuse Project (Phase 1) .................................. 18
List of Tables
Table 3-1: Cost Summary for Option H, Phase 1 ......................................................................................... 9
Table 3-2: Cost Summary for Option H, Phase 2 ....................................................................................... 10
Table 4-1: New Facilities Required for the Initial Phase of Option H ........................................................ 16
\\wc\shared\Projects\RMC\IRV\0305 - Encina Wastewater Authority\59 - Water Reuse FS\B. Project Work\4. Phasing\EWRFS_TM4_Phasing of Preferred Project.docx
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1 Introduction
Feasibility Study Background
As required by Encina Wastewater Authority’s (EWA) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) will identify a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd).
This Study will focus on developing a portfolio of options for potential reuse projects; identify and analyze
a short list of options; develop an approach to phasing of the preferred water reuse project—the focus of
this technical memorandum (TM); identify funding opportunities; develop a stakeholder involvement plan;
and coordinate with EWA member agencies and other stakeholders to engage with the Study development
and recommendations. Ultimately, the Study will serve to advance EWA’s mission of resource recovery
and contribute to sustaining and enhancing the region’s water resources.
Objectives
This TM presents a phasing approach to implementing Option H, which was identified under TM3 as the
preferred water reuse project for EWA. Option H primarily consists of raw water augmentation (RWA) into
the San Diego County Water Authority’s (SDCWA) Second Aqueduct, Pipeline No. 5.
As presented in TM3, Option H may also include groundwater augmentation (GWA) into the San Marcos
groundwater basin, which is within the Vallecitos Water District’s service area. However, the feasibility of
the smaller (~2 mgd) GWA aspect of Option H is dependent on:
• Moving forward with the larger (~16 mgd) RWA Project to deliver advanced treated water to the
Second Aqueduct in the vicinity of the San Marcos basin; and,
• Further investigation of the suitability of the San Marcos Basin for GWA.
If the GWA component of the Project is pursued, it is expected that the planning, design, permitting,
regulatory coordination, and other activities would be initiated and led by Vallecitos Water District.
Therefore, additional detail on the GWA aspect of Option H is excluded from this TM. Furthermore, given
the long history of GWA projects in California, the pathway to a GWA project in the San Marcos basin is
better understood and would require less early planning than the core RWA aspect of Option H.
This TM is organized as summarized below:
• Initial Phase for Secondary and Advanced Treatment Facilities
• Evaluation of Advanced Water Treatment Facility (AWTF) Size and Phased Expansion
• Framework Implementation Plan and Schedule
• Conclusions
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2 Initial Phase for Secondary and Advanced Treatment
Facilities
A comprehensive and efficient approach to ensuring that water quality requirements and goals are met for
EWA’s water reuse project includes changes to the existing secondary treatment provided at the EWPCF
to provide higher quality source water for the proposed AWTF. This is discussed in detail in TM3. Major
capital investments recommended include the following:
• Primary effluent flow equalization, including addition of new tankage and associated conveyance
infrastructure.
• Conversion of the secondary treatment process to biological nutrient removal, including retrofits to
the aeration basins to implement a nitrification – denitrification (NDN) process, such as the
Modified Ludzack-Ettinger (MLE) process.
• Tertiary filtration (e.g., addition of granular media filters).
Based on the improved treated effluent quality characteristics from the EWPCF, it is expected that pilot
testing and/or a demonstration study for the proposed AWTF treatment train will be required to confirm
expected performance and satisfy stakeholders (including project partners, regulators, and the public).
This section presents a step-by-step framework for the initial phase of improvements to the EWPCF and
the AWTF facilities proposed for the preferred option for EWA’s water reuse project.
EWPCF Improvements
The following steps are recommended for the first phase of EWPCF improvements:
1. Identify method to produce nitrified effluent from the EWPCF, including the following:
• Timeframe and cost for full nitrification to inform pilot studies
• Determine if nitrification in only a portion of the EWPCF is practical (e.g., one aeration basin)
• Determine approach to separating a side stream of primary effluent to run a pilot-scale NDN
treatment train
2. Identify location and approach to achieve primary equalization, evaluating the following:
• Use of the existing primary equalization provided by Aeration Basin No. 4 (and implications for
approach to NDN)
• Conversion of the East secondary equalization basin (and implications for peak wet weather flow
management)
• Construction of new primary equalization basin, considering siting and conveyance requirements
• Management of waste side streams (e.g., re-routing ahead of primary treatment and/or separating
from treatment train serving the AWTF)
3. Use a treatment process model/simulator to estimate projected secondary treatment performance for
the EWPCF and key water quality parameters for the influent to the AWTF.
4. Develop a preliminary design for the conversion to NDN treatment, including the following retrofits to
existing aeration basins and EWPCF systems:
• Baffle walls
• Mixers
• Mixed liquor return pumps
• Blower and aeration system requirements
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• Scum and foam control
5. Identify location of the two additional secondary clarifiers required for the increased flows at the plant.
6. Identify the location and requirements for tertiary filtration including the following:
• Type of filters
• Approach to disposal of backwash (location of return, equalization, etc.)
AWTF Pilot/Demonstration Study
A critically important part of the Project planning process is to determine the extent of a pilot or
demonstration study for the advanced purification technologies using effluent (treated wastewater) from
EWPCF. Typically, a pilot study is conducted over a shorter duration and at a smaller scale than a
demonstration study, while the facilities for a demonstration study are often intended for stakeholder
interaction and remain in use until a full-scale facility is near completion.
At a minimum, a pilot study is recommended as the initial phase to evaluate the effectiveness of the
proposed AWTF processes on the EWPCF secondary effluent, support public outreach, and test alternative
advanced oxidation processes. The piloting/demonstration phase would serve to test and develop design
criteria for the following AWT technologies, shown in Figure 2-1:
• Ozonation with biofiltration (O3/BAF)
• Ultrafiltration (UF)
• Reverse osmosis (RO)
• Advanced oxidation process (AOP) using ultraviolet (UV) light
• Stabilization (lime/CO2)
• Chemical dosing (e.g., free chlorine)
Figure 2-1: Proposed AWTF Treatment Train for RWA.
2.2.1 Test Plan Objectives
Prior to testing, a pilot/demonstration study plan should be prepared to determine the following
requirements:
• Location and options for pumping secondary effluent from EWPCF to pilot treatment train.
• Evaluate potential locations for the treatment train to be tested, considering process equipment
footprint, site access (for equipment setup and operations, deliveries, facility tours, etc.),
availability of electrical supply and SCADA connections, discharge of product water and reject
water, etc. Locations to be considered include the existing EWPCF, EWA’s South Parcel, and/or
the Carlsbad WRF site.
• Identify critical control points and monitoring strategies.
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• Review and determine timing requirements and approximate costs for pilot/demonstration studies.
It may be beneficial to conduct pilot tests in phases for separate testing of the different treatment
technologies that are proposed in the advanced water treatment train.
2.2.2 Operating Conditions and Performance
The pilot/demonstration plant would evaluate various operating conditions to aid in process optimization
and to determine recommended design criteria for a future treatment facility. Key conditions to evaluate
include:
• O3/BAF performance in reduction of TOC, pathogens, and nutrients
• MF/UF performance with acceptable intervals between chemical cleanings (e.g., at least 30 days)
by testing different operating conditions for flux, chemically enhanced backwash frequency, and
disinfection method
• RO performance with acceptable intervals between chemical cleanings (e.g., at least 180 days) by
testing different operating conditions for flux, recovery, membrane configuration, and membrane
type. RO testing could also be used for the following:
o Determine if a 2-stage or 3-stage RO configuration provides more efficient, reliable
performance at an 85 percent hydraulic recovery rate.
o Determine whether operation at a high flux rate (e.g., greater than 12 gfd) provides an
advantage or is a detriment to membrane fouling.
o Verify performance of alternative monitoring technologies such as online fluorescent dye
monitoring (e.g., Trasar®)
• UV AOP approach, including the following:
o Verify the performance of sodium hypochlorite (NaOCl) as an oxidant for the UV AOP.
o Evaluate the effectiveness of the UV AOP to destroy trace organic compounds not
completely removed by RO.
o Determine UV AOP effectiveness at destroying NDMA and other CECs, meeting the
minimum requirement of 1.2-log NDMA reduction and 0.5-log 1,4-dioxane reduction.
Baseline operating conditions for testing could be chosen based on operational information at existing
AWTFs. By optimizing these operating conditions through multiple testing runs, a more efficient and
effective treatment process can be designed for the future AWTF. The pilot/demonstration testing should
also confirm that the proposed treatment train can reliably meet the Project water quality goals, remove
constituents of emerging concern (CECs), and perform comparably to other operational AWTFs.
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3 Evaluation of AWTF Size and Phased Expansion
To achieve sufficient economies of scale and ensure the cost of water produced is reasonable, it is
anticipated that the initial project would produce approximately 16 mgd of advanced treated water. A
second phase expansion could potentially increase the production to 20 mgd based on the projected 2040
EWPCF flows, while still allowing for peak summer NPR production of 8 mgd at the facilities that rely on
EWPCF effluent (i.e., Carlsbad WRF and Gafner WRF). An additional expansion to 25 mgd production
may be possible if wastewater flows reach the liquid capacity of the EWCPF or if NPR demands decrease
in the future.
EWA Facilities Footprint Analysis
The AWTF for the preferred option at 16 mgd of production is estimated to require a total area of
approximately 290,000 ft2 (6.6 acres). Figure 3-1 shows the footprint of the assumed improvements to the
EWPCF, the AWTF sized for 16 mgd of production for RWA, and the RO concentrate (brine) disposal
connection to the Encina Ocean Outfall. If the AWTF were expanded to 25 mgd of production, the space
required would increase to approximately 390,000 ft2 (8.9 acres), which could still be sited within the 22.8-
acre footprint currently available at EWA’s South Parcel.
Conveyance and SDCWA System Integration
To accommodate the potential future increased flow to 20 or 25 mgd versus the “baseline” 16 mgd, the
pipeline to the SDCWA Second Aqueduct would need to be upsized from a 30-inch to a 36-inch, along
with increased pumping capacity at the pump station sited at the AWTF and at the booster pump station
required to match the pressure in the SDCWA raw water pipeline.
Activities to determine the requirements for integration with the SDCWA system may include the
following:
• Identify potential corridors for a 36-inch pipeline to convey up to 25 mgd maximizing use of public
right-of-way.
• Obtain utility information for selected potential alignments.
• Identify potential locations to connect to the Aqueduct and the SDCWA requirements.
• Perform preliminary hydraulic analysis to determine pump station(s) needs.
• Identify preferred alignment, size of corridor, easement requirements, etc.
• Update preliminary costs for conveyance of raw water to the Aqueduct.
• Summarize results in a Technical Memorandum.
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Figure 3-1: Project Treatment Facilities Footprint Layout (16 mgd RWA)
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Sensitivity Analysis of Conceptual Costs
Following the same methodology as outlined in TM3, a sensitivity analysis of the conceptual costs was
developed to consider the potential impact of increased availability of flow and/or outside funding sources.
For the purposes of the sensitivity analysis, the following phases and variants of Option H are presented:
• Phase 1: 20.5 mgd influent (16 mgd product water, for RWA only)
• Phase 2: 25.5 mgd influent (20 mgd product water, for RWA only)
A cost summary for each option is provided in Table 3-1 and Table 3-2, respectively.
Table 3-1: Cost Summary for Option H, Phase 1
Option H: RWA to Second Aqueduct (16 mgd) Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Treatment (FAT + O3/BAF) $234,400,000 at 20.5 mgd influent rate
Conveyance - East $157,000,000 at 20.5 mgd influent rate
Total Capital Cost $480,400,000
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $5,403,000 24/7/365 operations
Power - Conveyance $9,864,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $5,537,000 All new facilities (incl. EWCPF)
Labor $1,134,000 AWTF + Conveyance
Total Annual O&M Cost $21,938,000
Cost of Water
Annualized Capital Cost $21,450,000 2.0% rate, 30-yr term
Total Annual Cost $43,388,000 for first 30 years
Annual Yield 17,800 acre-feet
Unit Cost of Water $2,450 per acre-foot
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Table 3-2: Cost Summary for Option H, Phase 2
Option H4: SDCWA Second Aqueduct; Reduced
NPR Cost Notes
EWPCF Secondary Improvements $89,000,000 at 31 mgd flow rate
Advanced Treatment (FAT + O3/BAF) $281,511,221 at 25.5 mgd influent rate
Conveyance - East $191,900,000 at 25.5 mgd influent rate
Total Capital Cost $562,411,221
Annual O&M Costs
Power - Treatment (EWPCF + AWTF) $6,189,000 24/7/365 operations
Power - Conveyance $12,252,000 24/7/365 operations
Equipment Rehabilitation/Replace, Consumables $6,843,000 All new facilities (incl. EWCPF)
Labor $1,330,732 AWTF + Conveyance
Total Annual O&M Cost $26,615,000
Cost of Water
Annualized Capital Cost $25,112,000 2.0% rate, 30-yr term
Total Annual Cost $51,727,000 for first 30 years
Annual Yield 22,200 acre-feet
Unit Cost of Water $2,340 per acre-foot
A summary of the capital costs for each of the two phases for Option H is provided in Figure 3-2,
representing the difference in costs for the AWTF and conveyance. The required investment in EWPCF
improvements would be the same regardless of AWTF production.
Figure 3-2: Capital Cost Summary for Option H Phasing
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Figure 3-3 compares the cost of water for each phase with and without outside funding over the assumed
30-year financing period. The outside funding scenario assumes that grant funding would be obtained to
offset 20% of the capital costs, and that production incentives (local rebates) would reimburse the
participating agencies $500 per acre-foot for the first 25 years of operation.
Figure 3-3: Cost of Water Summary for Option H Phasing
Comparison of EWA Water Costs to Regional Alternatives
To evaluate the competitiveness of EWA’s Option H project, its associated costs to produce and deliver
advanced treated water for RWA were compared with the rates projected for SDCWA—the main water
wholesaler in the North San Diego County region. Although both untreated (raw) and treated rates for
SDCWA were reviewed, EWA’s RWA product water would be directly comparable to the raw water rates.
The SDCWA projected rate increases for the 2025-2045 period were based on a 10-year projection prepared
by SDCWA for the period 2017-2027. Projections of water rates after 2027 were developed by Helix Water
District and Padre Dam Municipal Water District in their financial analysis of a potential East San Diego
County surface water augmentation project and presented publicly on several occasions.
Note that the projections do not reflect the current status of litigation between SDCWA and MWD which
is pending a final ruling by a trial court following the 2017 Court of Appeals decision. These projections
also do not reflect MWD’s recent decision to finance approximately two thirds of the cost of the $15 Billion
California WaterFix twin tunnels Bay Delta Conveyance Project. This represents a significant increase from
the previous 26% MWD cost responsibility included in the rate projections shown in Figure 3-4 and is
expected to result in higher SDCWA water rates than anticipated. The water rates that are shown are in
comparison with the projected range of costs for EWA’s Option H on Figure 3-4. The range of costs for
Option H as shown are with capital costs inflated at 2.5 percent per year and O&M cost escalated at 1.5
percent annually.
$1,210
$547
$1,140
$451
$375
$375
$368
$368
$304
$304
$279
$279
$554
$554
$552
$552
$2,450
$1,780
$2,340
$1,660
$-
$500
$1,000
$1,500
$2,000
$2,500
$3,000
Option H
16 mgd RWA
Option H
16 mgd RWA
+ Funding
Option H
20 mgd RWA
Option H
20 mgd RWA
+ FundingCost of Water ($/af)Power
(Conveyance)
Power
(Treatment)
Other O&M
Annualized
Capital
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Figure 3-4: Comparative Cost of Water for EWA’s Option H and SDCWA Projected Costs
By identifying the points of intersection between the costs of water for EWA’s Option H and raw water
provided by SDCWA, Figure 3-4 shows that EWA’s project could be cost-competitive as early as 2025 or
as late as 2040, depending on flow available and level of outside funding. As previously noted, the
projections for SDCWA rates do not reflect the final decision in the SDCWA—MWD rate litigation and
exclude any additional cost increases associated with implementing the California WaterFix project, which
may accelerate the timeframe within which EWA’s project would become more cost-competitive.
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4 Implementation Plan and Schedule
Additional planning, pilot studies, environmental review, public outreach and regulatory discussion are
needed to refine the selected potable reuse project concept and verify economics. In addition, regulations
related to RWA are not expected until at least 2023 after further research is completed. To move the project
beyond this Study phase, additional work is required to address the following:
• Regulatory Activities
• Environmental Documentation
• Source Water Analysis
• Engineering, Design, and Construction
• Funding Plan and Applications
• Stakeholder/Public Outreach
The following sections present a summary of the activities under each category for the Preferred Project.
Regulatory Activities
As a first step, details of the regulatory strategy for the Preferred Project would be identified. Regulatory
oversight of potable reuse projects is carried out by DDW and the San Diego RWQCB. The general
responsibilities of each agency through the regulatory approval process are illustrated in Figure 4-1:
Figure 4-1: Regulatory Approval Process Steps.
Footnotes:
a ER – Engineering Report; ROWD – Report of Waste Discharge.
b Conditional approval may include conditions recommended by DDW for the RWQCB to include in the permit.
c The CEQA documentation must be certified before the tentative permit is released for public comment.
Engineering Report. As part of the DDW approval process, a draft Engineering Report must be submitted
to DDW and RWQCB. The purpose of the engineering report is to describe how the Project would comply
with the Title 22 Criteria, the Basin Plan, and SWRCB Plans and Policies. The report would include the
following types of information:
• Project purpose and goals
• Project participants (agencies or entities that would be in involved in the design, treatment,
distribution, construction, and O&M of the facilities)
• Applicable rules and regulations
Submit
Draft ER
and
ROWDa
DDW and
RWQCB
Review
Draft ER
Final ER Public
Hearing
DDW
Condition-
ally
Approves
Projectb
RWQCB
Issues
Tentative
Permitc
RWQCB
Holds
Public
Hearing
RWQCB
Issues
Final
Permit
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• Project facilities, including location, general design criteria for the treatment processes, reliability
features, etc.
• EWA’s industrial pretreatment/source control program
• Chemical quality of the source water (EWPCF raw wastewater)
• How compliance with the Title 22 Criteria pathogen control requirements would be achieved
• The quality of the recycled water and how it meets Title 22 Criteria
• The proposed monitoring program
• A contingency plan
The development of the draft Engineering Report and supporting technical studies is anticipated to take
approximately two and half years, with an additional six months to finalize the report (e.g., addressing
DDW and RWQCB comments and revising the text). The actual time necessary for finalizing the report
may be shorter or longer depending on the progress of other RWA projects in California, the availability of
DDW to review the draft report, and resolution of regulatory comments on the draft report.
Public Hearing. Once the report is finalized, the lead agency would schedule a public hearing to receive
comments on the project. DDW would attend the hearing. Following the public hearing, depending on the
comments received, DDW would send a letter to the RWQCB that conditionally approves the project and
recommends that the RWQCB issue a tentative permit. The approval letter may contain conditions that
must be implemented (and included in the permit) prior to operation of the project. The time necessary to
receive the conditional approval letter is a function of organizing the hearing, DDW availability to
participate in the hearing and approve materials to be presented at the hearing, and the time for DDW to
issue the approval letter. This overall process is estimated to take about three months.
RWQCB Permit – Waste Discharge and Water Recycling Requirements (WDR/WRR). A Report of
Waste Discharge (ROWD) for the proposed recycled water use is submitted to the RWQCB to initiate the
RWQCB permitting process. The ROWD must identify proposed treatment, discharge facilities and
operations, and characterize potential impacts on water quality. The ROWD is typically submitted along
with the draft Engineering Report. In addition, another ROWD would be required for the ocean outfall
National Pollutant Discharge Elimination System (NPDES) permit revision to discharge the proposed RO
brine to the Encina Ocean Outfall.
After DDW has issued its conditional approval letter and after the project’s California Environmental
Quality Act (CEQA) document is certified, the RWQCB would issue a tentative WDR/WRR. It is also
possible to request that EWA be given the opportunity to review a pre-public draft of the permit to resolve
any significant issues in advance of the public review period.
Ongoing Regulatory Coordination. It would be important to engage with DDW and RWQCB through
project permitting and implementation beginning early in the process. The DDW process is characterized
by ongoing consultation between the project proponent and DDW throughout the project planning,
predesign, design, and construction phases. Consultation with the RWQCB should occur both before and
after submittal of the ROWD. Pre-submittal consultation is directed toward ensuring that the ROWD is
structured to adequately address all RWQCB issues and concerns. Post-submittal consultation may be
directed toward addressing subsequent RWQCB questions or requests for additional information. The
timing and manner of engagement (e.g., in-person meetings versus conference calls) should be worked out
with the regulators based on their schedules and availability.
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Environmental Documentation
All public projects in California must comply with CEQA. If a project is not exempt, CEQA provides for
the preparation of an Initial Study (IS) to analyze whether the project would have a significant impact upon
the environment. A Negative Declaration/Mitigated Negative Declaration (ND/MND) could be issued if
the analysis in the IS determines that the project or action, as proposed or as proposed with specific
mitigation measures, would not have a significant impact upon the environment. If the analysis in the IS
determines that the project or action has the potential to result in a significant impact(s) to the environment,
then an Environmental Impact Report (EIR) would need to be prepared to further address such impacts. It
is anticipated that EWA will need to complete an EIR for the Preferred Project.
In addition to CEQA, a project is subject to National Environmental Policy Act (NEPA) if it is jointly
carried out by a federal agency, requires a federal permit, entitlement, or authorization, requires federal
funding, and/or occurs on federal land.
CEQA certification is required prior to RWQCB action to adopt the discharge permit. The RWQCB staff
typically defers preparation of the tentative discharge permit until after full CEQA certification has been
completed.
Source Water Analysis
Contaminants of Concern- Source Control Plan. An assessment will be required to determine the fate
of DDW-specified contaminants through the wastewater and recycled water treatment systems. The
constituents are those considered of importance based on industrial discharges to the wastewater system
and the source control program inventory of contaminants. These contaminants may include
pharmaceuticals, endocrine disruptors, and other wastewater indicator chemicals as specified by DDW
based on the review of the Engineering Report. In addition, EWA’s existing source control program should
be reviewed and augmented as necessary to satisfy the Title 22 Criteria.
EWPCF Effluent Monitoring and Operations Analysis. Analysis of the EWPCF current operational
procedures should be reviewed to determine their suitability to support the preferred project. Operational
improvement and optimization opportunities should be identified to increase the reliability of the secondary
treatment per the Title 22 Criteria.
Engineering, Design, and Construction Activities
The new facilities for Option H are summarized in Table 4. This section discusses the effort needed to
develop and implement the capital improvement projects identified for the initial phase, including EWCPF
improvements, construction of the AWTF, conveyance pump stations, pipelines, and conveyance of RO
brine to the Encina Ocean Outfall (EOO).
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Table 4-1: New Facilities Required for the Initial Phase of Option H
New Facility Description Quantity
EWPCF Improvements
• Primary Effluent Flow Equalization
• Secondary Process Conversion to MLE
• Tertiary Filtration
• 2 x 140-foot dia. tanks
• 4 aeration basins (retrofits), 2
new secondary clarifiers
• 6 tertiary filters
AWT Facility
• Treatment Facilities, including O₃/BAF,
UF, RO, AOP with UV/NaOCl, and
conditioning of product water
• Appurtenant Facilities, including
roadways, administration/maintenance
buildings, electrical facilities, product
water tank, and brine disposal to EOO.
• 16 mgd product water
Conveyance to SDCWA
Aqueduct No. 2 and
Integration with Pipeline
No. 5
• AWT product pump station
• Pipeline to RWA site
• Booster pump station
• 3 pumps, 5,600 hp
• 30 inch, 7.6 miles
• 3 pumps, 2,000 hp
O3 – ozone; BAF – biological activated filtration; UF – ultrafiltration; RO – reverse osmosis; UV – ultraviolet irradiation;
NaOCl – sodium hypochlorite; hp – horsepower; LF – linear feet; psi – pounds per square inch
Preliminary Design. Detailed facilities plans would be prepared for all the new facilities identified for the
project, including revised facilities layout for the AWTF, pipeline alignment evaluation, as well as revised
capital and O&M cost estimates based on vendor quotes and proposals. During preliminary design, the
concepts developed in this Study would be further refined, and assumptions would be updated, validated
and documented. The conveyance pipeline alignments and booster pump station siting would be addressed
as well. Alternative project delivery methods should be evaluated at this stage also (e.g., design-build vs.
traditional design-bid-build).
Final Design. Following pilot/demonstration testing and any recommended equipment pre-selection, the
design packages would be prepared for the AWT facilities. Design for conveyance pipeline and booster
pump station could proceed independently of the AWTF design. After permitting is completed, the bid
package would be prepared (assuming a design-bid-build approach).
Bidding/Contract Award, Construction, and Startup. Bidding and contract award would commence
once the bid package is complete. Following construction, a startup period of approximately 6 to 12 months
is anticipated, along with final approvals of the AWT facility and overall project.
Funding Applications
As described in TM5, the EWA Water Reuse Project would be eligible for funding from multiple federal,
state, and regional programs. To ensure the project maximizes its chances of receiving funding, a Funding
Plan could be prepared to confirm the potential funding sources and to identify the specific funding
assistance activities. Funding assistance activities include researching, identifying, and applying for federal,
state, and private foundation funding sources for utility-related projects including wastewater treatment
plant facilities and recycled water projects. This would further require the development of grant applications
tailored to specific projects in such a way as to make the projects more competitive for potential grant
funding. The necessary supporting technical and financial information is important when identifying how
much is needed in matching funds, including contributions from potential project partners. Funding
assistance activities are expected be required throughout implementation of the preferred project.
Pursuit of the Water Recycling Funding Program (WRFP) and San Diego Integrated Regional Water
Management (IRWM) Program grants could provide funding in the near-term, with Water Infrastructure
Improvements for the Nation (WIIN), Clean Water State Revolving Fund (SRF) Program, and MWD Local
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Resources Program / SDCWA Local Water Supply Incentive Program (LRP / LWSD) funding available in
the longer term.
Stakeholder/Public Outreach
A public information program is an essential element for the Water Reuse Project because of the importance
of educating and informing the public about the use of a new water supply and communicating that the
overwhelming scientific evidence has shown that potable reuse is a safe, feasible solution. An effective
public information program includes both outreach and participation, each serving different functions.
Outreach is a way of disseminating or collecting information to educate the public; participation implies a
means for stakeholders to actively engage in and influence a plan.
There is a track record of successful potable reuse projects that have the following characteristics in
common:
• They are designed to improve water quality;
• They augment water supplies or prevent seawater intrusion versus being designed to dispose of
wastewater;
• They maintain a database of historical water quality of treated effluent and conduct research to
support success;
• They are managed by agencies with established experience and that have gained the confidence of
regulatory authorities.
Thus, a public engagement program for the potential project should be initiated early in the planning process
and incorporated into EWA’s existing community relations program to reinforce the project purpose and
need. Elements of an outreach program to be developed for EWA may include:
• Planning Workshops. To identify EWA’s communication goal and objectives for the project,
project challenges and opportunities, and key messages and audiences
• Purpose and Need Statement. Review EWA’s reason for examining potable reuse and ensure that
the purpose and need for the project are clearly stated. This could be the basis for key messages,
informational materials, presentations and all other project communication.
• Survey. Conduct a baseline public opinion survey so that perceptions, awareness and knowledge
about water supply needs and sources, recycled water and potable reuse can be measured at the
very start of the project. Key messages could also be tested to determine if they help respondents
understand the project more clearly.
• Communication Plan. Develop a strategic communication plan that includes: a situation analysis;
project challenges and opportunities; EWA’s communication goal and objectives; strategies or a
list of how the goal and objectives would be accomplished; and outreach tactics, activities, and
communication tools that carry out the strategies and meet the goal or objectives.
• Informational Materials. Develop a fact sheet and frequently asked questions document that can
be posted on EWA’s website and printed for distribution at appropriate locations, including EWA
offices and at community presentations or events.
• Website. Evaluate the need for a separate project website or a page on EWA’s existing website.
Post all information about the potable reuse project on the website.
• Community Advisory Group. Consider establishing a community advisory group to work with
EWA staff and the project team on an identified task related to the project. This task could be for
the community advisory group to review the communication strategies and provide input on
additional ways to expand outreach about the project in the service area.
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Implementation Schedule
An overall implementation plan for the preferred project is shown schematically on Figure 4-2, which
indicates an overall duration of approximately ten years before project startup. Although there are currently
no permitted DPR projects in California (raw or treated drinking water augmentation), recent experience
with surface water augmentation projects is proceeding on similar timeframes (such as San Diego Pure
Water or the East County Advanced Water Purification Program) once a decision is made to proceed. Key
phases of the EWA RWA project and interdependencies are summarized as follows:
• Initial work should focus on planning for the major capital improvements (including a
pilot/demonstration phase) and developing the regulatory strategy for RWA.
• By the time the planning studies are completed, regulatory requirements for RWA projects should
be better defined, allowing the project to move ahead with preparation of the Engineering Report.
• Environmental documentation should be done in parallel with the design and DDW coordination
phases. CEQA certification is needed before RWQCB can issue the tentative permit.
• Construction of the project can begin after the RWQCB issues the final permit.
• Funding application and stakeholder/public outreach efforts will occur during the life of the project,
though the public outreach activities are not expected to ramp up until the pilot/ demonstration
facilities are operating.
Figure 4-2: Implementation Schedule for EWA’s Potable Reuse Project (Phase 1)
Planning
EWPCF Improvements
AWTF
Pilot Testing
Pipeline Alignment
Funding
Funding Plan
State
Federal
Regulatory
Strategy
Engineering Report
Permitting
Environmental
CEQA
Design/Construction
EWPCF Improvements
AWTF
Conveyance
Stakeholder/Public Outreach
Stakeholder Outreach
Public Outreach
Start of Project Operations
TASKS 9 1056784123
YEARS
●
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5 Conclusions and Next Steps
EWA’s wastewater flows and facilities represent a unique opportunity and a centralized location for large-
scale production of recycled water that could capture economies of scale to the benefit of the region. EWA’s
experience in water treatment and water quality may well make it suitable to take on the responsibility for
the AWTF required for potable reuse. The presence and available capacity of a deep ocean outfall is
conducive to siting the AWTF near the EWPCF for disposal of reject streams.
Demand for non-potable reuse in the region is not projected to be sufficient to fully utilize the available
effluent at the EWCPF, especially considering the seasonal nature of irrigation demands. Therefore, potable
reuse would be necessary to minimize discharges of EWPCF effluent to the Pacific Ocean. Although the
cost of water estimated for EWA’s RWA option is higher than current SDCWA untreated water rates (like
other recycled water projects being implemented in the region), SDCWA’s costs are projected to rise over
time and EWA’s RWA Project may become cost-competitive by the time it could begin delivering water
in the mid to late 2020s.
Because the production of a new water supply by EWA is not required to comply with its NPDES permit
or any other state or federal requirement, the cost of the RWA Project beyond wastewater treatment and
disposal would be the responsibility of water purveyors. As such, future planning and implementation
activities should be pursued on a cost share basis with participating local and regional water suppliers.
However, it should be noted that the draft Amendment to the Recycled Water Policy released by the
SWRCB on May 9, 2018 identified the following:
• Goal: Increase the use of recycled water from 714,000 afy in 2015 to 1.5 million afy by 2020 and
to 2.5 million by 2030.
• Goal: Minimize the direct discharge of treated municipal wastewater to […] ocean waters, except
where necessary to maintain beneficial uses. Under this goal, treated municipal wastewater does
not include brine discharges from recycled water facilities or desalination facilities.
• The State Water Board will evaluate progress toward these goals and revise the goals or establish
mandates as necessary.
As shown on the RWA Project Implementation Schedule included in Section 4 above, the activities
identified during the initial phases of the Project are focused on:
• Identifying the potential impacts on the EWPCF.
• Refining the design criteria for the AWTF and pilot testing.
• Strategizing the approach to defining the regulatory requirements for RWA.
• Developing a funding plan to maximize the opportunities for outside funding.
• Determining a likely corridor for the conveyance pipeline to the SDCWA raw water pipeline.
If EWA’s Board of Directors authorizes staff to continue planning and permitting activities beyond this
Study, future stakeholder outreach should focus on developing a formal partnership with the water
purveyor(s) that would use the purified raw water produced from EWPCF effluent. The anticipated cost of
recommended activities over the first two years is estimated to be approximately $800,000. This cost will
likely be shared by local and regional water purveyors interested in continuing to refine the costs and
partnering on the project.
Defining EWA’s role after the Feasibility Study will be key to any implementation plan of wider reuse of
EWA’s valuable water resources. EWA should invite continued discussions with its potential partners
(retail water agencies), and the next steps could also involve significant policy and financial deliberations
by its Board and Member Agencies.
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July 2018 1
Technical Memorandum No. 5
EWA Water Reuse Feasibility Study
Subject: Funding Opportunities
Prepared for: Encina Wastewater Authority
Prepared by: Alexis Cahalin, Rosalyn Prickett, AICP | Woodard & Curran
Reviewed by: Nathan Chase, P.E., Scott Goldman, P.E. | Woodard & Curran
Ken Weinberg | Ken Weinberg Water Resources Consulting LLC
Date: July 2018 (Draft Issued: October 2017)
Contents
1 Introduction and Background ................................................................................................................ 2
1.1 Background ................................................................................................................................... 2
1.2 Objectives ..................................................................................................................................... 2
2 Regional Funding .................................................................................................................................. 3
2.1 San Diego IRWM Program ........................................................................................................... 3
2.2 MWD Local Resources Program .................................................................................................. 5
3 State Funding ........................................................................................................................................ 7
3.1 Clean Water SRF Program ............................................................................................................ 7
4 Federal Funding .................................................................................................................................... 9
4.1 Title XVI Water Reclamation and Reuse Program ....................................................................... 9
5 Conclusions ......................................................................................................................................... 11
5.1 Summary of Funding Opportunities for EWA’s Reuse Project .................................................. 11
5.2 Recommended Next Steps .......................................................................................................... 13
List of Tables
Table 1: Funding Program Financial Benefit Example ............................................................................... 11
Table 2: Funding Program Ranking ............................................................................................................ 12
\\wc\shared\Projects\RMC\IRV\0305 - Encina Wastewater Authority\59 - Water Reuse FS\B. Project Work\5. Funding\EWRFS_TM5_Funding.docx
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1 Introduction and Background
1.1 Background
As required by Encina Wastewater Authority’s (EWA) 2020 Business Plan, the Water Reuse Feasibility
Study (Study) will identify a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd).
The Study will focus on developing a portfolio of options for potential reuse; identify and analyze a short
list of options; develop an approach to phasing of the preferred water reuse project; identify funding
opportunities for projects; develop a stakeholder involvement plan; and coordinate with EWA Member
Agencies and other stakeholders to engage with the Study development and recommendations. Ultimately,
the Study will serve to advance EWA’s mission of resource recovery and contribute to sustaining and
enhancing the region’s water environment.
1.2 Objectives
The purpose of this technical memorandum (TM) is to identify local, state, and federal funding
opportunities for EWA’s water reuse project. For each funding source, the TM explains the funding
program objectives, eligibility criteria, cost share requirements, and activities that could be funded, thereby
reducing the cost to local agencies and their retail water customers. The TM is organized as follows:
• Regional Funding: San Diego Integrated Regional Water Management (IRWM) Program,
Metropolitan Water District of Southern California (MWD) Local Resources Program, and a
potential San Diego County Water Authority (SDCWA) Local Water Supply Development
Program.
• State Funding: Clean Water State Revolving Fund (SRF) Program, and Water Recycling Funding
Program.
• Federal Funding: Title XVI Water Reclamation and Reuse Program, and Water Infrastructure
Improvements for the Nation (WIIN) Program.
• Conclusions: Conclusions regarding the level of funding that could be available for project
implementation, as well as recommendations for funding future phases of the project development
process if EWA and any partnering agencies determine there is a feasible project to move forward
with.
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2 Regional Funding
2.1 San Diego IRWM Program
The Integrated Regional Water Management (IRWM) Grant Program is supported by bond funding through
the California Department of Water Resources (DWR). This program funds competitive grants for multi-
benefit projects that develop long-term water supply reliability, improve water quality, and protect natural
resources. Funding is distributed regionally and applied for at the local level.
Proposition 1 provides $52.5 million for the San Diego Funding Area (which includes southern Orange and
Riverside counties) for projects that help meet the long-term water needs of the State. Eligible grant
applicants include public agencies, non-profit organizations, public utilities, federally-recognized Indian
Tribes, state Indian Tribes listed on the Native American Heritage Commission’s Tribal Consultation list,
and mutual water companies.
The San Diego IRWM Program – managed by a Regional Water Management Group (RWMG) comprised
of San Diego County Water Authority (SDCWA), County of San Diego, and City of San Diego – will
receive $38.2 million for distribution to local water resource management projects. The application process
occurs through the local program prior to and concurrent with each round of funding made available by
DWR. One round of Proposition 1 funding has already been awarded locally, totaling $4.9 million, which
leaves $33.3 million available for future rounds. The IRWM Grant Program will fund planning, design,
environmental, and construction costs. The San Diego IRWM Program requires inclusion of public outreach
and construction components in all funded projects.
Eligible project types for the IRWM Grant Program are announced with each solicitation, but generally
include the following:
a. Water reuse and recycling for non-potable reuse and direct and indirect potable reuse.
b. Water-use efficiency and water conservation.
c. Local and regional surface and underground water storage, including groundwater aquifer cleanup
or recharge projects.
d. Regional water conveyance facilities that improve integration of separate water systems.
e. Watershed protection, restoration, and management projects, including projects that reduce the risk
of wildfire or improve water supply reliability.
f. Storm water resource management projects.
g. Conjunctive use of surface and groundwater storage facilities.
h. Water desalination projects.
i. Decision support tools to model regional water management strategies to account for climate
change and other changes in regional demand and supply projections.
j. Improvement of water quality, including drinking water treatment and distribution, groundwater
and aquifer remediation, matching water quality to use, wastewater treatment, water pollution
prevention, and management of urban and agricultural runoff.
The San Diego IRWM Program application process typically begins approximately six months prior to
DWR’s deadline, with a local Call for Projects. One or more workshops are generally held before and
during the Call for Projects for local project sponsors to identify opportunities to strengthen their project
and receive assistance with submitting their project for consideration. Submitted applications are scored in
accordance with the scoring criteria established by the Regional Advisory Committee (RAC) for that round
of funding, and project scores are presented to stakeholders for comments. Following project scoring, a
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workgroup is selected from RAC members. The workgroup evaluates each project and conducts interviews
with project sponsors, finally selecting a list of projects for that round of funding. The list of selected
projects is then approved by the RAC. Once the project list is approved, the RWMG and consultants
preparing the grant application coordinate directly with the project sponsors to obtain required information
to prepare the application for submittal to DWR. To date, DWR has approved and fully awarded all of the
San Diego IRWM Program’s grant applications.
DWR anticipates two rounds of implementation funding for Proposition 1. Applications for the first round
of funding are anticipated to be due to DWR in late 2018, and the second round is anticipated to occur in
2020. Funding availability for the two future rounds is uncertain, but estimated by the San Diego IRWM
program to be $10-15 million in 2018 and $18-23 million in 2020. These grants require a minimum of 50%
local cost share. Projects that score well in the San Diego IRWM Program are multi-benefit, have multiple
(public and/or non-profit) partners, and have substantial public outreach components.
Evaluation for EWA Water Reuse Project
EWA’s Water Reuse Project would be competitive under the San Diego IRWM Program because water
reuse is a priority for the Region. The project would address multiple goals and objectives of the San Diego
IRWM Plan including improving the reliability and sustainability of regional water supplies, protecting and
enhancing water quality, watersheds and natural resources, and promoting and supporting sustainable
integrated water resource management.1
EWA could become involved in the San Diego IRWM Program by attending RAC meetings as a member
of the public, and potentially volunteering to sit on the RAC when the next set of seats become available at
the end of 2018. EWA could also contribute projects during the Call for Projects for each round of funding,
and attend public workshops associated with the funding opportunities. Participation in the San Diego
IRWM Program is open to any entity involved in water management and would not have to be done through
EWA’s Member Agencies.
Proposition 1 funding via the IRWM Grant Program could be used for planning, design, and construction
activities. However, projects must be “shovel-ready” to be eligible for the IRWM Grant Program. Although
planning components can be included, the project must contain a construction component that will deliver
physical benefits (e.g., result in recycled water deliveries) to be funded. EWA might consider phasing the
construction components and beginning design and CEQA compliance on early construction components,
so that those deliverables can be submitted with the application. EWA might also consider coupling the
planning phase of the Water Reuse Project with one or more capital projects at the EWPCF so that the total
package is “shovel-ready”. All IRWM-funded projects must also contain a public/stakeholder outreach
component that exceeds minimum regulatory (e.g., CEQA or Title 22) requirements.
The local process for the next round of Proposition 1 funding is anticipated to begin in early to mid-2018.
The subsequent round of Proposition 1 funding is anticipated to occur in 2020. EWA should become
engaged with the San Diego IRWM Program by end of 2017 to receive all relevant information for the next
funding opportunity. There is no maximum award level (minimum is $500,000), but the largest award to
date was $6 million and the average award was $1.5 million.
The San Diego IRWM Region project prioritization and selection process would dictate whether EWA’s
Project would be included in an application. Additional information is requested from projects selected for
1 Additional details on the San Diego 2013 IRWM Plan’s goals and 11 objectives can be found in Chapter 2 of the
IRWM Plan, http://sdirwmp.org/pdf/SDIRWM_02_Vision_Objectives_Sep2013.pdf
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inclusion in the Region’s application, which is then used by the RWMG and its consultant team to develop
the Region’s application to DWR.
2.2 MWD Local Resources Program
The Metropolitan Water District of Southern California (MWD) has provided incentives for the
development of local water supply projects since 1982. The Local Resources Program (LRP) began by
providing up-front capital; after operation began, MWD would recover costs by selling its share of water
to the participating agency. Since then, the LRP has evolved into a system in which MWD pays the agency
for project water deliveries, essentially subsidizing the higher cost of water that water agencies may face
when developing a recycled water or groundwater recovery project. Today, there are three payment options,
consisting of the following:
1. Sliding scale incentives up to $340/AF over 25 years
2. Sliding scale incentives up to $475/AF over 15 years
3. Fixed incentive up to $305/AF over 25 years
The sliding scale incentives are calculated annually based on actual project unit cost exceeding MWD’s
prevailing water rate. The LRP is open to public and private water agencies within MWD’s service area.
Eligible projects are listed below, provided they include construction of new substantive treatment or
distribution facilities:
a. Water recycling projects
b. Groundwater recovery projects
c. Seawater desalination projects
Since the program began, 78 water recycling projects and 25 groundwater recovery projects have been
approved, for a total of 432,000 AFY expected production upon completion2. Not all funded projects are
operating at full capacity. Total investment to date is approximately $571 million.
MWD is currently involved in on-going litigation with SDCWA over its rates. SDCWA has filed four
lawsuits against MWD to date, in 2010, 2012, 2014, and 2016, claiming that MWD illegally charged
SDCWA for transporting conserved Colorado River water through MWD’s conveyance system. SDCWA
also claimed that MWD’s Rate Structure Integrity(RSI) provision which was included in LRP and water
conservation funding agreements was unconstitutional. The RSI provision prevented agencies involved in
litigation or legislation challenging MWD’s rate structure from receiving LRP or conservation funding.
In June 2017, the State Court of Appeal issued its opinion on the 2010, 2012 and 2014 litigation and among
other findings ruled that MWD’s RSI language was unconstitutional and could not be used to bar SDCWA
from LRP and conservation funding. MWD did not appeal that ruling to the California Supreme Court
which in September 2017 denied SDCWA’s petition for review on other issues and the appellate ruling
became final. Now, SDCWA and its member agencies are once again able to receive LRP funding. Since
that time, SDCWA member agencies began developing their applications for submittal to the LRP Program.
SDCWA has pending litigation which it filed in 2016 that challenges MWD Water Stewardship Rate that
funds LRP. The status of that lawsuit and its effect on future LRP agreements are unknown presently.
2 MWD Board Report on MWD’s Efforts to Encourage Local Resources Development,
http://www.mwdh2o.com/PDF_About_Your_Water/2794_001.pdf
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SDCWA Local Water Supply Development Program
SDCWA had its own water supply incentive program that was originally intended as a supplement to
MWD’s LRP based on financial need. Established in 1991, the program was originally called the Reclaimed
Water Development Fund (RWDF) and was later changed to the Local Water Supply Development
(LWSD) Program. The program provided agencies up to $100/AF of recycled water produced and
beneficially reused within SDCWA’s service area, which offset a demand for imported water. In 2005, the
program was amended to eliminate the requirement that award of funding was contingent upon receiving
MWD’s LRP funding. In 2006 and 2008, the program was amended to allow eligible projects to include
brackish and contaminated groundwater recovery projects and seawater desalination projects and the
incentive amount was increased to up to $200/AF. In 2010, the LWSD Program ceased accepting new
applications because it was believed there was no longer a financial need for SDCWA to provide its own
incentive.
In November 2017, SDCWA initiated a Cost of Service Study (COSS) that will also examine the
formulation of a new SDCWA local projects incentive program. This potential Local Water Supply
Incentive Program (LWSIP) is expected to be consistent with SDCWA legal claims in their 2016 lawsuit.
It is anticipated that the COSS and a proposal for a potential LWSIP will be completed by Spring 2018.
It is likely that, between MWD’s LRP eligibility and SDCWA’s evaluation of its own program, regional
financial incentives would be available for the EWA Water Reuse Project that would reduce cost for local
ratepayers.
Evaluation for EWA Water Reuse Project
Because applicants must be a member agency of SDCWA or be sponsored by a member agency, EWA
would be required to partner with a member agency; or, more likely, the member agency that beneficially
reuses the recycled water would apply on their own and EWA would remain solely in a wholesaler role.
The terms of a Water Purchase Agreement between EWA and the end user of the supply would assign roles
and responsibilities among the parties. It is reasonable to expect that responsibility for obtaining either
MWD or SDCWA financial incentives is more properly the role of the water supply agency.
The LRP incentives apply to the cost of delivered water only, so they may be achieved only after all
construction and start-up activities are complete. These programs do not provide financial support prior to
operations such as during the planning, design, or construction phases. Currently, MWD has a target of
annual water production under the LRP Program of 63,000 AFY. MWD has contracted for some portion of
that target and may have to raise that target for the EWA Water Reuse Project. Continued uncertainty in
imported water availability and comments by MWD staff indicate that relooking at that target which was
adopted in 2009 is likely in the coming years.
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3 State Funding
3.1 Clean Water SRF Program
The Clean Water State Revolving Fund (SRF) Program is administered by the State Water Resources
Control Board’s (SWRCB) Division of Financial Assistance. The SRF Program provides below-market
rate financing to assist communities in preventing pollution of water resources. Repayments of loan
principal and interest earnings are recycled back into SRF Program to finance new projects that allow the
funds to "revolve" at the state level over time. Eligible applicants are any city, town, district or public body
created under state law; Native American tribal governments or authorized Native American tribal
organizations having jurisdiction over disposal of sewage, industrial waste or other waste; any designated
management agency under Clean Water Act §208; and 501(c)(3)s and National Estuary Programs.
The Clean Water SRF Program will fund construction costs and associated soft costs (e.g., planning, design,
administration) as estimated in the application. Following contract execution, budget values are refined
based on the final construction bid for the project.
Eligible projects include, but are not limited to the following:
a. Publicly-owned treatment works
b. Nonpoint source projects
c. National estuary program projects
d. Decentralized wastewater treatment systems
e. Storm water projects
f. Water conservation
g. Watershed projects
h. Energy conservation
i. Water reuse projects
j. Security measures at publicly-owned treatment works
k. Technical assistance
Funds would be limited only by EWA’s ability to borrow, and no match is required. Loan terms include
30-year amortization and low interest rates. Repayment begins one year after construction is complete.
SWRCB can offer principal forgiveness (i.e., grants) to applicants if the project directly benefits a small,
disadvantaged community (DAC).
The Clean Water SRF application process occurs at the state level. Four different application packages are
submitted to the SWRCB – general information, technical, environmental, and financial security packages.
The application preparation and review process takes 9-12 months, and loans are awarded based on
readiness-to-proceed (e.g., CEQA-Plus [state and federal environmental compliance documentation]
completed and approved by SWRCB). Applications are currently accepted on a rolling basis but may
transition to a formal application window in the future.
Although early disbursement requests can cover soft costs only, generally it is preferable to be ready for
the construction bid process by completion of the SRF application process. SWRCB staff require submittal
of and conduct their own federal environmental consultations with U.S. Fish & Wildlife Agency and State
Historic Preservation Office as part of the application review process. Additionally, any necessary
Wastewater Change Petition must be completed prior to application approval.
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It should be noted that the Clean Water SRF Program is currently oversubscribed. However, because it is a
revolving fund (i.e., 50% of all repayments are available for future awards), the status of the SRF Program
could improve by the time a financing agreement with the SWRCB would be executed for the EWA project.
Water Recycling Funding Program
The SWRCB administers the Water Recycling Funding Program (WRFP) concurrent with the SRF Program
to promote the beneficial use of treated municipal wastewater to augment fresh water supplies. The WRFP
provides technical and financial assistance in support of water recycling projects and research. Proposition
1 provided $625 million under the WRFP for planning and construction of water recycling projects, which
is being administered through the Clean Water SRF. Applications are accepted on an ongoing basis.
Two categories of grants are offered, planning grants and construction grants, which are described below:
1. Planning grants: Planning studies for facilities to determine the feasibility of using recycled water
to offset the use of fresh/potable water from state and/or local supplies are eligible. Pollution control
studies, in which water recycling is an alternative to disposal, are not eligible. The facilities
planning report must include analysis of all the essential components of the project and identify a
recommended project.
o A 50% match is required.
o The maximum grant award is $75,000. Funding is still available in this category.
2. Construction grants: Eligible applicants for construction grants are local public agencies, non-
profit organizations, public utilities, federally- and state-recognized Native American Tribes,
mutual water companies, and JPAs. Financial and technical assistance is available for projects that
offset or augment state fresh water supplies. Projects focused on system process efficiencies
including, but not limited to, operations and maintenance (O&M) and process improvements not
regulated by a waste discharge permit, are ineligible to receive funding.
o A 50% match is required.
o The maximum grant award is 35% of the total project cost or $15 million, whichever is
less. However, SWRCB has reported that all of the WRFP construction funding has been
allocated; construction grants are no longer available. Recent passage of Senate Bill 5
(California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for
All Act of 2018) may provide additional funding for the WRFP, but it is uncertain at this
time whether additional funding will be available under this program.
Evaluation for EWA Water Reuse Project
EWA and partnering agencies would likely qualify for planning grants and low-interest financing through
the Clean Water SRF Program and WRFP. EWA could apply immediately for a WRFP planning grant,
which would provide up to a $75,000 grant toward completion of a Feasibility Study, requiring a 50%
match. JPAs are eligible entities for planning grants. EWA could utilize WRFP planning grant funds to
expand this Study to meet SWRCB and USBR requirements, so that it complies with both Clean Water
SRF and Title XVI/WIIN requirements.
Clean Water SRF would provide a low-interest loan (current interest rate is 1.7%) up to the full project cost.
Additional construction grant funds could be obtained through the WRFP if additional funding becomes
available. Clean Water SRF loans are approved on a first-come, first-serve basis following approval of
submitted applications. Because the application review process takes 9-12 months, the status of the SRF
Program is expected to improve by the time a construction application is ready for the EWA Project.
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4 Federal Funding
4.1 Title XVI Water Reclamation and Reuse Program
The United States Bureau of Reclamation (USBR) WaterSMART: Title XVI Water Reclamation and Reuse
Program (Title XVI Program) includes funding for the planning, design, and construction of water recycling
and reuse projects, including prior costs. The purpose of the Title XVI Program is to develop and
supplement urban and irrigation water supplies through water reuse, thereby improving efficiency,
providing flexibility during water shortages, and diversifying water supply. A water reuse project is a
project that reclaims and reuses municipal, industrial, domestic, or agricultural wastewater and naturally
impaired groundwater and/or surface waters. Reclaimed water can be used for a variety of purposes such
as environmental restoration, fish and wildlife, groundwater recharge, municipal, domestic, industrial,
agricultural, power generation, or recreation.
To receive Title XVI funding for a construction project, the project must receive congressional
authorization (which has not occurred in the last few years due to the congressional earmark ban). Once a
project has congressional authorization, a Title XVI Feasibility Study must be submitted to USBR for
review and approval. USBR will then provide a Determination of Feasibility, which provides eligibility to
pursue the annual Funding Opportunity Announcements (FOAs). Both USBR and congressional approval
are required to be eligible to pursue Title XVI funding. The federal share for a Title XVI project shall not
exceed 25%, up to the value authorized by Congress.
A Title XVI application is submitted in response to the annual FOAs and is evaluated against all other
applications received from the Western States. The application requires project information and response
(limited to 75-pages) to a series of evaluation criterion questions related to water supply, environment and
water quality, energy efficiency, economic benefits, disadvantaged communities, and watershed
perspective.
Water Infrastructure Improvements for the Nation (WIIN) Program
The WIIN Program is a subset of the Title XVI Program, established for agencies that have not received
congressional authorization under Title XVI. The purpose of the WIIN Program is to develop and
supplement urban and irrigation water supplies through water reuse, thereby improving efficiency,
providing flexibility during water shortages, and diversifying the water supply.
This program includes $50 million for Title XVI projects that have received a Determination of Feasibility
(i.e., they have submitted and received approval of a Feasibility Study from USBR), but have not been
congressionally authorized. The federal share for a WIIN project shall not exceed 25%, up to $20 million.
The WIIN Program is being administered similarly to the Title XVI Program, and the FOA for the 2017
fiscal year (which offered $10 million for WIIN grants) was released on July 17, 2017. The next round of
funding under the WIIN Program may be available as soon as Fall or Winter 2017.
The application process for WIIN grants is similar to the Title XVI Program, with comparable application
requirements and evaluation criterion.
Evaluation for EWA Water Reuse Project
The USBR WIIN Program could be used to fund planning, design, and/or construction of all potential
project components. Construction activities can be phased to pursue construction of different components
of the Project in each 2-year funding cycle until the $20 million grant is achieved. USBR does not award
the full $20 million at once. EWA can submit multiple applications under the annual FOAs, with a fraction
of the $20 million grant received each time.
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EWA would need to submit a Title XVI Feasibility Study to receive a Determination of Feasibility, after
which the project would be eligible to apply for a WIIN grant. USBR does not expect to receive
congressional authorizations for any new Title XVI projects – all future projects will now follow the WIIN
process.
The FOA for this program is expected to be released annually in the Fall, with USBR moving toward a
joint Title XVI/WIIN solicitation in the future. The Project would then be in direct competition with all
other authorized and unauthorized projects. Projects that include a construction component score higher in
the WIIN grant process. EWA might consider phasing the construction components and beginning design
and CEQA compliance on early construction components, so that those deliverables can be submitted
with each application.
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5 Conclusions
5.1 Summary of Funding Opportunities for EWA’s Reuse Project
Five of the funding programs described in this TM are most applicable to various components of EWA’s
water reuse project. Table 1 is a summary of the impact of each funding program on the potential cost of
water produced by the EWA Project, based upon the conceptual cost opinions developed under TM4 for
Option H3. For simplicity, all costs are shown in 2017 dollars.
Table 1: Funding Program Financial Benefit Example
Program Assumption Capital Cost Cost of Water
(incl. O&M) % Reduction
Baseline
(No Funding Support)
Assumes financing with a 30-year loan
at 2% interest rate $480 million $2,450/AF N/A
San Diego IRWM Assumes $5 million grant award $475 million $2,440/AF 0.4%
SWRCB WRFP Assumes $15 million grant award $465 million $2,410AF 1.6%
USBR WIIN Program Assumes $20 million grant award $460 million $2,400/AF 2.0%
SWRCB Clean
Water SRF Program
Assumes low interest loan for the full
Project cost at 1.7% interest rate No change $2,400/AF 2.0%
MWD LRP /
SDCWA LWSIP
Assumes $540/AF incentive (LRP:
$340/AF for 25 years + LWSD:
$200/SF for 25 years)
No change $2,000/AF 4 18.4%
For each of the funding programs described above, the projected capital cost and cost of water has been
calculated assuming the stated award. If EWA were to secure financial benefits from all programs identified
in Table 1, the overall projected reduction in the cost of water could be up to 24.5% based upon the
following:
• $440 million total capital cost
• $1,850/AF cost of water
Several water supply agencies within the region have capitalized on multiple grant and loan programs in
this way.
3 Note that the funding opportunities used in this example could apply to other EWA Reuse Project Options also.
4 To facilitate comparison to the other programs, this assumes the incentive subsidies per acre-foot are in place for
the first 25 years, and a return to the baseline non-subsidized cost for the remaining 5 years of the 30-year term loan.
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As explained in Table 2, pursuit of WRFP and San Diego IRWM Program grants could provide funding in
the near-term, with WIIN, SRF Program, and LRP / LWSD funding available in the longer term. The five
programs are ranked as follows:
1. The WRFP ranks first because EWA could apply for a planning grant to support preparation of a
Feasibility Study for the Water Reuse Project. Funding is available in the planning grant program.
2. The San Diego IRWM Program ranks second because it is the least competitive of the available
programs and there is substantial funding available. However, EWA would need to be creative in
developing a “Project” that meets the eligibility requirements, with some “shovel-ready”
components.
3. The Title XVI WIIN Program is ranked third because it offers a larger grant maximum and the
solicitations are expected to occur annually. However, the program is highly competitive, and a
Title XVI Feasibility Study must be prepared to be eligible.
4. The Clean Water SRF Program ranks fourth because the program is currently oversubscribed, and
it can take 9-12 months for the application review process to be complete. That said, it offers low
interest rates that would be beneficial for such a large capital project and should be pursued once
the Project is further along.
5. The LRP / LWSIP Programs are ranked last because of the uncertainty of their reinstatement and
their timing after construction and start-up. These programs should be tracked and applied for when
the Project is farther along, if funds are available.
Table 2: Funding Program Ranking
Rank Program Explanation
1 SWRCB WRFP WRFP planning grant funds are currently available and could support
development of a Feasibility Study with up to $75,000 at a 50% match.
2 San Diego IRWM
Program
IRWM funding is a strong option because the competition occurs at the regional
scale, where local water agency partners can be an advocate for the EWA
Project. Planning activities can be paired with other “shovel-ready” capital
projects to secure grant funding (using the capital project costs as match) or
phased to allow for work to proceed in stages.
3
USBR Water
Infrastructure
Improvements for the
Nation (WIIN) Program
WIIN funding could be used to fund planning, design, and/or construction of all
potential project components. Construction activities can be phased to pursue
construction of different components of the Project in each 2-year funding cycle
until the $20 million grant is achieved.
4
SWRCB Clean Water
State Revolving Fund
(SRF) Loan Program
EWA and partnering agencies would likely qualify for low-interest financing
through the Clean Water SRF Program, which would cover construction activities
up to the full project cost. Extensive application materials are necessary,
including completion of CEQA and all permits.
5
MWD Local Resources
Program / SDCWA
Local Water Supply
Incentive Program
The LRP and LWSIP are likely to become available to SDCWA member agencies
again; however, the timeline or availability of funds is uncertain. Further, these
funds only apply to the cost of delivered water, so they may only be awarded
after all construction and start-up activities are complete.
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5.2 Recommended Next Steps
To increase the chances of receiving funding for any future phases of EWA’s water reuse project, it is
recommended that EWA and any partnering agencies pursue all funding options available. In the short term,
the following actions should be considered to further refine the project and position EWA and any partners
for existing and future funding opportunities:
• Partner Agreements: EWA should identify one or more water agency partners to begin pursuing
funding opportunities for the initial phases of work. Development of one or more MOUs with
partner agencies may help facilitate funding pursuits by outlining roles and responsibilities.
• WRFP Planning Grant Application: EWA could apply for WRFP planning grant funding to
support preparation of complete Feasibility Studies that, in turn, could be used in applying for
additional funding as described below.
• Clean Water SRF/WRFP and Title XVI/WIIN Feasibility Studies: EWA should develop
additional content to supplement this Study to ensure it complies with the requirements for a Clean
Water SRF/WRFP and Title XVI/WIIN Feasibility Study, which would enable the project
proponents to submit applications for funding with SWRCB and USBR. WRFP planning grant
funding could be secured to support this effort.
• San Diego IRWM Grant Application: EWA could develop a package of activities that includes
planning for the Water Reuse Project, as well as other capital projects at the EWPCF. If this is
pursued, EWA should become engaged in the IRWM Program through RAC and stakeholder
meetings.
• CEQA Environmental Review: Due to the construction phasing that is allowed by the WIIN and
San Diego IRWM Programs, EWA might consider preparing a Program Environmental Impact
Report (EIR) that addresses all facilities that may be necessary for the Project. EWA would then
complete project-level CEQA through either Supplements or Addendums to the Program EIR,
depending on the level of anticipated impacts for each individual project component as those are
moved forward into various funding programs.
• Clean Water SRF Application: As an initial step, EWA could prepare and submit General
Information forms to get in the queue for the Clean Water SRF. This notifies SWRCB and others
that the EWA Project will proceed and provides information about expected funding needs. In turn,
this allows SWRCB to lobby for additional allocations from water bonds or the Legislature. If funds
become available, this could ensure EWA is in a favorable position to obtain funding (e.g., for
detailed facilities planning for a first phase of the Project).
• Pilot Phase Funding: Once a pilot phase scope of work is determined and the Title XVI/WIIN
Feasibility Study is complete, EWA could prepare applications for WIIN and San Diego IRWM
funding for full-scale pilot facilities that would produce advanced treated water for potable reuse
as an initial phase of the ultimate project.
• Funding Opportunity Tracking: Ongoing tracking of funding opportunities that may emerge and
be relevant to EWA’s reuse project, including attending workshops and coordinating with funding
agencies to determine eligibility and define requirements for application, is essential to be ready
for each opportunity as it arises.
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July 2018 1
Technical Memorandum No. 6
EWA Water Reuse Feasibility Study
Subject: Stakeholder Involvement Plan
Prepared for: Encina Wastewater Authority
Prepared by: Ken Weinberg | Ken Weinberg Water Resources Consulting, LLC
Rosalyn Prickett | Woodard & Curran
Reviewed by: Nathan Chase, P.E., Scott Goldman, P.E. | Woodard & Curran
Date: July 2018 (Draft Issued: December 2016)
Contents
1 Introduction and Background ................................................................................................................ 2
1.1 Background ................................................................................................................................... 2
1.2 Objectives ..................................................................................................................................... 2
2 EWA’s Role as Water Wholesaler ........................................................................................................ 3
2.1 Existing Capabilities and Drivers for Increased Reuse ................................................................. 3
2.2 Financial Considerations ............................................................................................................... 3
3 Stakeholder Identification ..................................................................................................................... 5
3.1 Core Stakeholders for this Study .................................................................................................. 6
3.2 Regulatory Agencies ..................................................................................................................... 6
3.3 EWA Board of Directors ............................................................................................................... 6
4 Stakeholder Outreach ............................................................................................................................ 7
4.1 Initial Outreach to Member Agencies ........................................................................................... 7
4.2 Stakeholder Workshops ................................................................................................................ 7
4.3 Timeline of Stakeholder Activities ............................................................................................... 9
5 Next Steps ........................................................................................................................................... 10
5.1 Memorandum of Understanding ................................................................................................. 10
Appendix A – Letter of Support ................................................................................................................. 11
List of Figures
Figure 3-1: Stakeholder Diagram for EWA Water Reuse ............................................................................ 5
Figure 4-1: Timeline of Stakeholder Activities ............................................................................................ 9
List of Tables
Table 1: Summary of Initial Outreach Letters Sent and Responses Received .............................................. 7
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1 Introduction and Background
1.1 Background
As required by Encina Wastewater Authority’s (EWA's) 2020 Business Plan, this Water Reuse Feasibility
Study (Study) will identify a path to maximize beneficial reuse of effluent from the Encina Water Pollution
Control Facility (EWPCF)—which by 2040 is projected to reach an average of approximately 31 million
gallons per day (mgd).
This Study focuses on development of a portfolio of options for potential reuse projects; identification and
analysis of a short list of options; development of an approach to phasing of the preferred water reuse
project; identification of funding opportunities; development of a stakeholder involvement plan—the focus
of this technical memorandum (TM); and coordination with EWA member agencies and other stakeholders
to engage with the Study development and recommendations. Ultimately, the Study will serve to advance
EWA’s mission of resource recovery and contribute to sustaining and enhancing the region’s water
environment.
1.2 Objectives
The purpose of this TM is to develop a stakeholder involvement plan that identifies the stakeholder activities
to be completed as part of this Study and provides an overview of potential next steps for the ultimate water
reuse project. The TM is organized as summarized below:
• EWA as Water Wholesaler: this section will define EWA’s role as a water wholesaler and identify
the goals for water pricing to ensure the ultimate project allows full cost recovery (at a minimum)
to EWA.
• Stakeholder Identification: this section provides a listing of local and regional stakeholders along
with key contacts. Stakeholders will depend on the options that are investigated, but as a minimum
are anticipated to include EWA Member Agencies, the San Diego County Water Authority, and
the North San Diego County Reuse Coalition.
• Stakeholder Outreach: this section provides the methodology and timing for conducting
stakeholder workshops as part of this Study, as well as how the outcomes of the workshops will be
captured and communicated.
• Potential Next Steps: the final section identifies potential stakeholder activities that may be
required for the next stage of the water reuse project arising from this Study, including discussion
of the anticipated role for EWA.
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2 EWA’s Role as Water Wholesaler
Although EWA is taking the lead at this stage by developing this Water Reuse Feasibility Study, its role as
a project proponent needs to be well-defined prior to engaging stakeholders. EWA would likely be the
producer of recycled water, while the local water purveyors and others will ultimately control the end
beneficial use. Developing the roles and responsibilities of EWA in a large-scale beneficial reuse project is
critical to the formation of a business case and structure to implement a project if it is found to be technically
and financially feasible.
2.1 Existing Capabilities and Drivers for Increased Reuse
EWA facilities represent a unique centralized location for large-scale production of recycled water that
could capture economies of scale to the benefit of the region. The regulatory standards for beneficial use of
recycled water are continuously evolving and expanding the potential market for recycled water supplies.
This expanding market of permitted uses requires the availability of increased and cost-effective production
of recycled water that can meet Title 22 non-potable standards or undergo advanced treatment for potable
reuse under existing Indirect Potable Reuse (IPR) regulations or under future Direct Potable Reuse (DPR)
regulations.
EWA’s mission and core competencies are centered on the collection, treatment, and disposal of
wastewater. Although authorized by its Board of Directors to be involved in developing water resources
and specifically recycling wastewater for beneficial uses, EWA is not in the business of the retail
distribution of recycled water. That would be outside of EWA’s jurisdiction as a joint powers authority
(JPA) and would require an expansion of its historic role and core competencies. Also, under California
anti-paralleling laws, EWA would have significant difficulty in distributing recycled water to potential
customers without the permission and cooperation of local water purveyors.
EWA’s experience in water treatment and water quality may well make it suitable to take on the
responsibility for the Advanced Water Treatment (AWT) required for potable reuse. The presence and
availability of a deep ocean outfall is conducive to siting the AWT facility near the EWPCF. In addition, a
portion of the 28 acres available at EWA’s South Parcel could be used as the site of the AWT facility, which
would be consistent with the requirement of utilization for EWA-mission related purposes. This is a
decision EWA should thoughtfully consider and it would still be consistent with a wholesaler role.
Given the constraints discussed above and its fiduciary responsibilities to wastewater ratepayers, the most
appropriate role for EWA in maximizing beneficial reuse in North San Diego County and possibly
throughout the region is as a wholesaler of recycled water. This role would be similar to certain
characteristics of the San Diego County Water Authority (SDCWA) role as a wholesaler of imported water
and desalinated seawater to retail water purveyors.
2.2 Financial Considerations
To facilitate engagement with external stakeholders on the concept of EWA as a recycled water wholesaler,
this section identifies certain aspects and financial bottom lines of that role. While EWA’s relationship with
its (potential future) wholesale recycled water customers will function as a partnership, it is also a business
arrangement and key business issues are best defined as early in the process as possible. It is important to
articulate these business features to potential retail water purveyors or other wholesale customers as wider
participation in a potential reuse program is discussed.
While at this early stage of feasibility analysis it may not be possible to identify all the aspects of a wholesale
structure, it may be possible to develop a framework around the known bottom line positions, as well as
acknowledging those deal points that EWA is open to discussing with the stakeholders concerning its role
in the potential project. Aspects of a water reuse project to consider will include costs for planning, design,
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and construction of new facilities and improvements to existing facilities; ownership and operation of new
facilities; permitting and compliance responsibilities; and financing and application for low interest loans,
grants, and incentives.
EWA must consider its requirement to collect revenues for all its activities and note that the allocation of
costs between wastewater ratepayers and water ratepayers will be a critical aspect of any cost responsibility
and cost recovery structure. Currently, the clearest demarcation is defined by EWA’s existing NPDES
permit requirements. In the event those permit requirements change, or changes are made to State law
limiting ocean outfall discharge volumes, additional cost allocation methods should be considered.
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July 2018 5
3 Stakeholder Identification
Through an initial stakeholder identification effort, Figure 3-1 below was developed to provide a
comprehensive view of stakeholders that may be involved in the planning and implementation of potential
EWA water reuse projects.
Figure 3-1: Stakeholder Diagram for EWA Water Reuse
Because EWA is at an early stage of feasibility planning and has not yet determined whether it is either
cost-effective or within its organizational mission to implement a project, a focused stakeholder
involvement plan is appropriate to engage only those stakeholders considered essential to the development
of the Feasibility Study. Additionally, EWA’s likely role as wholesale supplier of recycled water would
suggest that it initially conduct a focused outreach to its potential wholesale customers and not the general
public. It is the retail water purveyors that have the direct relationship with the public and input from the
public will be vitally important at a future phase if a program or project advances beyond feasibility
planning.
Another factor in using a targeted outreach is to avoid setting expectations among external stakeholders
prior to EWA’s Board of Directors (Board) determining how best to use the information arising from the
Feasibility Study and deciding what, if any, future action should be taken to develop a water reuse project.
As a wholesaler whose potential customers include several EWA Member Agencies, the decision on
whether a project is technically and economically viable ultimately rests with both the Board and the water
purveyor agencies.
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EWA Water Reuse Feasibility Study
TM6: Stakeholder Involvement Plan
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3.1 Core Stakeholders for this Study
The proposed stakeholder outreach effort recognizes that neither EWA, its individual Member Agencies,
nor the retail water purveyors have made any decision to move forward on what are the yet unknown results
of the Study. These stakeholders are identified on the inner circle of Figure 3-1 and include both EWA
Member Agencies and other entities that might be part of the projects identified in the Study’s Portfolio of
Options.
With the exception of the City of San Diego, the San Diego County Water Authority, San Dieguito Water
District, and Poseidon Resources, these agencies are all members of the North San Diego Water Reuse
Coalition (NSDWRC) and have conducted extensive planning on how to maximize the beneficial use of
available recycled water supplies. This core group of stakeholders is very educated on the topic of non-
potable and potable water reuse, and their expertise will allow informed discussions and decisions by all
the parties to proceed expeditiously. Their participation is also critical because many of the NSDWRC
partners have invested in their own recycled water treatment and conveyance facilities, and it will be
important to ensure that those assets are not stranded in the future. Definition of the EWA wholesale market
will need to make sure that existing demands and users are not double-counted.
3.2 Regulatory Agencies
Although beyond the scope of the current Feasibility Study, discussions with regulatory agencies will be
an important part of any future stakeholder outreach. Informal discussions with regulatory agencies during
the Feasibility Study may be beneficial to better evaluate the feasibility of the Options being considered as
they are an important participant and source of critical information. Water reuse opportunities are
constrained by the existing or anticipated regulatory environment, and the water purveyor(s) will be
identified through determining the best means of complying with the regulatory scheme in a cost-effective
manner.
In the event that additional studies and project development activities occur following the completion of
the Feasibility Study, the San Diego Regional Water Quality Control (Regional Board) and the State Water
Resources Control Board’s Division of Drinking Water (DDW) should be considered major stakeholders
to be engaged in those future technical discussions.
3.3 EWA Board of Directors
The EWA Board of Directors (Board) is also a primary stakeholder in this process as they are the final
evaluators of the Study and whether EWA will move beyond the feasibility planning stage. Providing
updates and opportunities for discussion of strategic and business issues during development of the
Feasibility Study will help keep the Board engaged in the process. The Board’s input will be critical to the
results of the Study and key features of EWA’ s relationship with the water purveyors.
Board involvement should be concurrent with the core stakeholder outreach activities and is expected to be
accomplished through two Board workshops. It is recommended that a Board workshop be scheduled
following each stakeholder workshop. In this way, the Study Team will be able to provide the Board with
the input received from the stakeholder discussions regarding the progress of the Feasibility Study and
related policy issues, along with the technical advancements of the Study. This approach will provide
opportunities for the Board to give input into Study development and will familiarize the Board with the
key policy issues prior to hearing the final results and EWA staff recommendations.
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EWA Water Reuse Feasibility Study
TM6: Stakeholder Involvement Plan
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4 Stakeholder Outreach
4.1 Initial Outreach to Member Agencies
The initial outreach activity was directed at EWA Member Agencies through a letter from EWA’s General
Manager to each individual Member Agency informing them of the commencement of this Feasibility
Study and requesting confirmation of current data relating to existing recycled water commitments,
treatment capacity, peak demand estimates, and future plans for indirect potable or direct potable reuse (see
Table 4-1). This information is critical to the development of the Portfolio of Options.
Table 4-1: Summary of Initial Outreach Letters Sent and Responses Received
Agency Date of Letter
from EWA
Date of Agency
Response
City of Carlsbad 10/28/2016 11/22/2016
City of Encinitas 10/28/2016 N/A
Leucadia Wastewater District 10/28/2016 10/31/2016
Vallecitos Water District 10/28/2016 N/A
City of Vista / Buena
Sanitation District 10/28/2016 10/28/2016
Vista Irrigation District 10/31/2016 11/3/2016
In addition to the letters, a presentation was made to the Member Agency Managers on November 1, 2016
to brief them on the Feasibility Study and discuss the initial Portfolio of Options, as well as the planned
stakeholder activities.
4.2 Stakeholder Workshops
It is recommended that subsequent outreach to stakeholders will consist of the following:
• Two workshops, where collectively the local water purveyors will work with EWA staff and the
Study Team to review the progress of the Feasibility Study and provide feedback on the initial
recommendations.
• One-on-one technically-oriented meetings, as needed, where specific project alternatives will be
refined in partnership with the potential water purveyor.
Because the NSDWRC is an established structure, it will provide a useful vehicle for advancing the goals
of the Feasibility Study and integrating the local water retailers into the process. The NSDWRC meets
regularly and their meetings present an ideal venue to hold workshops and achieve a high level of
stakeholder participation.
Study Team members presented an overview of the Feasibility Study and the outreach approach to the
NSDWRC at their November 7, 2016 meeting. It was agreed that the December monthly meeting would be
used to conduct Workshop 1. Along with the NSDWRC, representatives of the City of San Diego and the
SDCWA were also invited to attend the same meeting. At the current stage of analysis, the alternatives
involving Poseidon are not considered to be favorable compared to other alternatives; therefore, Poseidon
is not being considered for targeted outreach at this time.
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TM6: Stakeholder Involvement Plan
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4.2.1 Workshop 1: Portfolio of Options
The goals of Workshop 1 will include achieving stakeholders’ familiarity with the Study Team,
understanding EWA’s desire to complete the Feasibility Study with input from the local water purveyors,
provide an overview of technical approach to the Feasibility Study, and to present the technical details
around the Portfolio of Options and the process used for selecting a “shortlist” for further consideration.
Another goal of Workshop 1 is to begin the conversation of what a water reuse partnership between EWA
and the water purveyors could look like. This will be the initial identification of a business structure.
The agenda for Workshop 1 will include the following:
• Introduction of Feasibility Study and Historical/Regional Context
o Emphasize EWA’s desire to obtain feedback from the local water purveyors to develop the
best alternatives possible and to identify what if any next steps should be taken.
• Overview of the Study’s Technical Approach and Schedule
o Build on work done by NSDWRC
o Process for identifying and screening reuse opportunities
o Regulatory context and assumptions for potential project timing and phasing
• Discussion of EWA’s Role in Maximizing Reuse
o Indicating EWA’s initial positions relative to how the business relationship can be
structured.
o Discussion of cost responsibility assumptions, ownership of facilities and permit
responsibilities. EWA Member Agencies will be in attendance at the Workshop and will
be representing their agency’s wastewater and water supply interests, as applicable.
• Discussion of the Study’s Portfolio of Options and Ranking
o Describe the range of alternatives and potential timing of implementation.
o Seek a consensus through group discussion on the initial screening criteria and the highest
ranked alternatives.
• Action Items, Next Steps, and Overview of Workshop 2
4.2.2 Workshop 2: Best Option and Phasing
The purpose of Workshop 2 will be to present the Preferred Option of water reuse projects to potentially
develop further for future consideration. Workshop 2 will begin with a review of what was accomplished
in Workshop 1, including any updates to the Portfolio of Options, screening criteria, and ranking.
The Study Team will present its evaluation of the options and how it arrived at the Preferred Option and
suggested phasing. As part of Workshop 2, the Study Team will review cost estimates, cost estimating
methodology, and provide a financial analysis of the option’s annual capital and operating costs. The
financial analysis will also include identification of potential funding options that can reduce the cost to
EWA and water purveyor ratepayers. It is important to note that the financial analysis will not include cost
allocation approaches between wastewater and water agencies.
The agenda for Workshop 2 will include the following:
• Portfolio of Options Screening Criteria Review
• Refinements to Preferred Option(s)
• Financial Analysis
o Overall Cost per acre-foot
• Stakeholder Input Requests
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o Review of draft Feasibility Study results
o Encourage attendance at the EWA Board meeting where the Study will be presented to
demonstrate their engagement and support
4.3 Timeline of Stakeholder Activities
Following completion of Workshop 2 and finalization of the Study’s technical memoranda, the Study Team
will prepare a final draft Feasibility Study for EWA review.
The final Feasibility Study and any recommendations should have the engagement and support of the retail
water agencies. Ideally, presentation to the Board of the final Feasibility Study should include comment
letters supporting the Feasibility Study and recommended next steps by one or more of the water agencies’
General Managers. Figure 4-1 below depicts the sequence of stakeholder activities.
Figure 4-1: Timeline of Stakeholder Activities
Expressions of Support
Ahead of the EWA Board Meeting at which the Draft Feasibility Study was presented, a letter of support
was received from the General Manager of Olivenhain Municipal Water District (OMWD (see Appendix
A). At the meeting itself, the General Manager of San Elijo Joint Powers Authority (SEJPA) made a public
comment in support of the Feasibility Study, thanking EWA’s Board of Directors and staff for their
leadership on this Study. Both OMWD and SEJPA are members of the NSDWRC.
EWA
Board
Mtg.
•Present Draft
Feasibility
Study
Stakeholder
Workshop
2
•Invite: key
stakeholders
•Present Best
Option and
Phasing
•Present
Financial
Analysis
EWA
Board
Mtg.
•Briefing on
Study and
Progress
Stakeholder
Workshop
1
•Invite: MAs,
SDCWA,
NSDWRC, City
of SD
•Present Study
Background
and Shortlist of
Options
Initial
Outreach
•Letters to
EWA's
Member
Agencies (MAs)
periodic briefings to MAM throughout
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TM6: Stakeholder Involvement Plan
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5 Next Steps
In the event that the Board authorizes EWA staff to continue planning and permitting activities beyond the
Feasibility Study, future stakeholder outreach should be focus on developing a formal partnership with the
water purveyor(s). Defining EWA’s role in the post-Feasibility Study timeframe will be key to any
implementation plan of wider reuse of EWA’s valuable water resources. It will invite continued discussions
with its potential partners, the retail water agencies, and could involve significant policy and financial
deliberations by its Board and Member Agencies.
5.1 Memorandum of Understanding
An early step in the future stakeholder process could be development of a Planning Memorandum of
Understanding (MOU) between EWA and the participating water purveyor(s). The Planning MOU would
focus on roles, responsibilities and potential cost sharing between EWA and the partner agencies for
additional planning work. It could also identify joint stakeholder outreach activities for a potential project,
which will include additional entities shown in
that were not formally engaged in the Study phase.
The Planning MOU would define the mutually agreeable next steps for project development. Some of the
key aspects for EWA to consider in defining its future role in a Planning MOU could include:
• Willingness to cost-share with partnering agencies for the next round of studies to move projects
forward with potential for EWA receiving reimbursement later.
• EWA can offer to fulfil an administrative role on project implementation, especially with regard to
AWT and conveyance infrastructure, permitting and zoning, water treatment operations expertise,
construction management, etc.
• Future regulatory changes may have a major impact on EWA’s role (e.g., a bill by Senator
Hertzberg mandating reduction in ocean discharges of treated wastewater). This may require a more
active and phased approach to EWA’s role that can be considered in future planning efforts.
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Appendix A – Letter of Support
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24422 Avenida de la Carlota, Suite 180
Laguna Hills, California 92653
949.420.5300
woodardcurran.com
Sept. 27, 2022 Item #10 Page 279 of 279
One Water North San Diego
Scott McClelland, P.E., BCEE
General Manager
Our Ask: Join Us In
One Water North San Diego
What is One Water North San Diego?
Non-Potable Reuse(NPR)
Level of Complexity
Existing
[Carlsbad/
SEJPA/
Olivenhain]
Groundwater Augmentation (IPR)
Surface Water Augmentation (IPR)
Raw Water Augmentation (DPR)
Treated Drinking Water Augmentation (DPR)
Level of Complexity+++
[City of SD]
Level of Complexity
++++
Level of Complexity
+++++
Level of Complexity++
[Oceanside]
Existing Regulations Regulations Expected by end of 2023
Ask: Become an Advocacy Agency
‣Cooperate with EWA in refining project concepts and costs
‣Review and provide input on outreach materials and deliverables
‣Advocate and solicit additional regional partners (wholesale and retail)
‣Participate in project concepts, regulatory, and pursuit of funding
‣Engage in discussion of potential institutional arrangements
‣Consider financial participation in future phases
The Time is Now
UncertaintyIn times of drought and water supply uncertainty, we need reliable, local supply
FundingWe need to capitalize on available funding opportunities
SustainabilityReduced ocean discharge is better for the environment
Drought Impacts Region
NPR –September 1, 2022
New Local Sustainable Supply
8%Local Surface Water6%Groundwater
11%Seawater Desalination
9%Recycled Water
13%Canal Lining Transfer
33%IID Water Transfer
2%MWD
18%Potable Reuse
With this project 18,000-25,000 AFY of potable reuse water could be created by 2040
Water Authority’s 2035 Projected Supply Mix
North County Needs a
One Water North San Diego
Demand > Supply
The Schedule
‣TimelineYears 1 2 3 4 5 6 7 8 9 10
Planning
Funding
Regulatory
Environmental
Design/Construction
Stakeholder/Public Outreach
Next Steps: Advocacy Activities
‣Meet with potential Advocacy Agencies
‣Discuss and develop Project concepts & alternatives
‣Refine Project concepts
‣Complete funding and regulatory strategies
‣Update concept designs and cost estimates
‣Complete Potable Reuse Strategic Plan
Join Us In
One Water North San Diego