HomeMy WebLinkAboutSP 144A; SDG&E Wastwater Facility; Specific Plan (SP)APPLICATION FOR COASTAL DEVELOPMENT PERMIT
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£'*'' V ' 'f< ,% '- LOCAL AGENCY REVIEW FORM
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[SECTION A (To be completed by-applicant)! \ J^O A°^^
Appl leant -SDG&E I • >j.^i-v--:--.^ '.- •••'•'•. -• V . '
Project description Demolition (grading) of existing Wastewater Treatment Ponds
Location • Encina Power Plant ~- *t600 Carlsbad Boulevard •
>l "Assessor's Parcel Number 210-010-33
.SECTION B (To be completed by local planning or building inspection department)!
.Zoning designation : •••••' l/Uj&'JjfaJj&j ftj/'tf du/ac
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General or Communi ,ty PI an desi gna ti on ' /AJ^i&w Mfl du/ac. ,.;, .,..;V- , ..__ . .-••:! ..^{ :•:.-, $ : -• .
Local Discretionary Approvals . ' ;
development meets all zoning requirements and needs no local permits
other than building permits.- -/
Q'P'roposed development needs local discretionary approvals noted below.
Needed Received ' . , " ''••".'
DO Design/Architectural review.
D D Variance for _ .
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' ' ;O : D Rezone from •
D 3- D . Tentative'Subdivision/Parcel Map No. _ _ '
[D^~ O Grading/Land "Development Permit No. _ _
O -D Planned Residential /Commercial Development
D ft " Si te, PI an; Review ,
D: ' D Condominium Conversion Permit
O \ . CU Conditional , Special , or Major Use Permit No.
D:" "D ; -Other
CEQA Status . ' .:" -•' ', '•
Categorically Exempt - Class Item
D Negative Declaration Granted .^ _____ _ __
Q Environmental .Impact Report Required, Final Report certified _
Prepared for the(pty)c.ounty of C0^^H^ byI / N^, ___ y —"* •' ........ •' ....... •...•^ " ..- . ^-^
Date i Title
DATE: April 8, 1991
TO: File
FROM: Adrienne Landers
SUBJECT: Wastewater Ponds Removal; Environmental Review
It has been determined by staff that the environmental review
necessary for removal of the wastewater treatment pond removal is
exempt from CEQA per Section 21000 et. seq. Public Resources Code,
in accordance with Section 15321, Chapter 3, Title 14, California
Code of Regulations. In addition, it was determined pursuant to
Section 15051(b) of CEQA that the California Water Regional Quality
Board was the Lead Agency and would obtain a Coastal Development
Permit from the Coastal Commission. The only approval necessary
from the City of Carlsbad is approval of a grading permit.
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD
SAN DIEGO REGION
CEASE AND DESIST
ORDER NO. 88-81
FOR
SAN DIEGO GAS & ELECTRIC COMPANY
ENCINA POWER PLANT
CLASS I SURFACE IMPOUNDMENTS
SAN DIEGO COUNTY
The California Regional Water Quality Control Board, San Diego Region, (hereinafter Regional
.Board) finds that:
1. On December 21, 1987. the Regional Board adopted Cease and Desist Order No. 87-138 for
violations of Waste Discharge Requirement Order No. 87-137.
2. Subsequent to adoption of Orders Ncs. 87-137 and 87-138, the discharger decided to close
the existing surface impoundments rather than upgrade the impoundments to meet the
requirements of the Toxic Pits Cleanup Act of 1984 and Subchapter 15, Chapter 3, Title 23
of the California Code of Regulations (Subchapter 15). By letter dated May 9, 1988, the
discharger reported to staff its intent to replace the impoundments with above-ground
tanks (for the metal cleaning and treated wastes) and an in-line treatment system (for the
low volume nonhazardous wastes). This decision was based on a cost and feasibility
analysis of retrofitting the surface impoundments to current standards, notably the seismic
design criteria as prescribed in Subchapter 15.
3. SDG&E's decision caused several discharge specifications contained in Order No. 87-137
to become obsolete. Therefore, Order No. 88-80 reflects necessary modifications to Order
No. 87-137, "Waste Discharge Requirements for San Diego Gas & Electric Company,
Encina Power Plant, Class I Surface Impoundments, San Diego".
4. TPCA prohibits any person, after June 30, 1988, from discharging liquid hazardous wastes
or hazardous wastes containing free liquids into a surface impoundment if the surface
impoundment contains hazardous waste and is within one-half mile of a potential source of
drinking water, and requires the person in that event to close the surface impoundment or
be granted an exemption with specific restrictions.
5. Waste Discharge Requirements Order No. 88-80 contains the following Prohibitions:
"A.2. The discharge of liquid hazardous wastes or hazardous wastes containing free
liquids to the existing surface impoundments after June 30, 1988 is prohibited.",
and
"A.3. The discharge of restricted hazardous waste into the surface impoundments is
prohibited."
CAD Order No. 88-81 -2-
6. The discharger intends to discharge wastes to the present surface impoundments until the
above-ground tanks are operational. Therefore, the discharger threatens to violate
Prohibitions A.2 and A.3 of Order No. 88-80 by the discharge of restricted hazardous
and/or liquid hazardous waste or hazardous wastes containing free liquids into the surface
impoundments after June 30, 1988. Documentation of the threatened violations are
contained in the August 22, 1988 Regional Board staff report and oral testimony presented
to the Board at a Public Hearing on August 29, 1988.
7. The discharger intends to comply with Order No. 88-80 by installing above-ground tanks
for the discharge and storage of restricted hazardous wastes, liquid hazardous wastes,
and/or hazardous wastes containing free liquids. The discharger has provided a schedule
for implementation of the above-ground tanks and for cease discharge to the surface
impoundments. The time schedule and Cease Discharge Order are based on the schedule
provided by the discharger,
8. Cease and Desist Order No. 87-138 was issued by the Board on December 21, 1987 for
violations of Waste Discharge Requirements Order No. 87-137. The directives contained
in Cease and Desist Order No. 88-81 replace those established in Cease and Desist Order
No. 87-138.
9. SDG&E has been informed of the threatened violations through correspondence, by-
meetings with Regional Board staff, and from the August 22, 19S8 Staff Cease and Desist
report.
10. On August 29, 1988 in Room B-109 of the State Office Building, 1350 Front Street, San
Diego, after due notice to the discharger and all other interested persons, the Regional
Board conducted a public hearing at which evidence was received concerning the
aforementioned threatened violations of Order No. 88-80.
11. This enforcement action is exempt from the provisions of the California Environmental
Quality Act in accordance with the California Code of Regulations. Title 14. Section
15308."
IT IS HEREBY ORDERED, that San Diego Gas & Electric Company (SDG&E) shall comply with
the following:
1. SDG&E shall cease and desist from violating Prohibitions A.2. and A.3. of Order No. 88-80
for the Encina Power Plant.
2. Compliance by SDG&E with Prohibition A.2. and A.3. of Order No. 88-80 shall be
achieved in accordance with the following time schedule:
Compliance Report Due
Task Date Date
(a). Submittal of a preliminary closure plan. 12,31/88 12/31,88
(b). Submittal of a detailed closure plan. 5.31 89 5 31/89
CAD Order No. 88-81 -3-
(c). Cease discharge of liquid hazardous waste or
hazardous waste containing free liquids into
existing surface impoundments. 7/31/90 8/15/90
(d). Initiate closure and cleanup. 8/01/90 9/15/90
(e). Finish closure and cleanup. 8/01/91 9/15/91
3. The discharger shall submit to the Regional Board quarterly progress reports detailing
progress made toward cease discharge, closure, and cleanup. These reports shall be due
30 days following the end of each quarter (January 30, April 30. July 30, and October 30).
4. The discharger shall submit to the Regional Board, on or before each compliance report
date, a report of compliance or noncompliance with the specific task. If noncompliance is
being reported, the reasons for such noncompiiance shall be stated, plus an estimate of
the date of compliance. The discharger shall notify the Regional Board by letter upon
return to compliance with the time schedule.
5. The discharger shall suspend and, or limit discharge of any liquid hazardous waste (or
restricted hazardous waste if produced) into the present surface impoundments until new
above-ground tank construction is complete or unless a vita! power plant cleaning
operation is required to prevent damage.
6. Until the new above-ground tank construction is complete, any restricted hazardous
wastes, liquid hazardous wastes, or hazardous wastes containing free liquid discharged to
the surface impoundments shall be removed within 30 days. Documentation of the
approximate liquid volume removed, disposal destination (chemical analyses if necessary to
determine disposal method), and the duration liquid was in the surface impoundment(s)
shall be submitted to the Regional-Board.
7. The discharger shall submit documentation and/or "as-builts" of completion of the above-
ground tanks and in-line treatment facilities upon completion.
8. The discharger shall submit documentation that cease discharge has been achieved.
PROVISIONS
1. Nothing in this Order shall be construed to preclude SDG&E from civil or criminal
penalties resulting from violations of Order No. 88-80.
2. The California Water Code provides that any person who intentionally or negligently
violates a Cease and Desist Order issued, reissued or amended by a Regional Board is
subject to a civil monetary remedy of discharge, up to $10,000 per day of violation or
some combination thereof.
3. The requirements prescribed by this Order supersede the requirements prescribed by
Cease and Desist Order No. 87-138. Cease and Desist Order No. 87-138 is hereby
rescinded upon issuance of this Order.
C&D Order No. 88-81 -4-
1, Ladin H. Delaney, Executive Officer, do hereby certify the foregoing is a full, true, and
correct copy of an Order adopted by the California Regional Water Quality Control Board,
on August 29, 1988.
LADIN H. DELANEY
Executive Officer
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD
SAN DIEGO REGION
ADDENDUM NO. 1
TO
CEASE AND DESIST ORDER NO. 88-81
FOR
SAN DIEGO GAS & ELECTRIC COMPANY
ENCINA POWER PLANT
CLASS I SURFACE IMPOUNDMENTS
California Regional Water Quality Control Board, San Diego Region
(hereinafter Regional Board) finds that:
1.
2.
3.
On August 29, 1988, the Regional Board adopted Cease and
Desist Order No. 88-81 for San Diego Gas & Electric Company
(SDG&E) for threatened violations of Prohibitions A. 2 and
A. 3 of Waste Discharge Requirements (WDR) Order No. 88-80.
Directive No. 2 of Cease and Desist Order No. 88-81
established the following schedule for compliance with
Prohibition A. 2 and A. 3 of WDR Order No. 88-80:
Task
(a) Submittal of a preliminary
closure plan.
(b) Submittal of a detailed
closure plan.
(c) Cease discharge of liquid
hazardous waste or hazardous
waste containing free liquids
into existing surface
impoundments.
(d) Initiate closure and cleanup.
(e) Finish closure and cleanup.
Compliance
Date
12/31/88
5/31/89
7/31/90
Report Due
Date
12/31/88
5/31/89
8/15/90
8/01/90
8/01/91
9/15/90
9/15/91
By letter dated March 21, 1990, SDG&E notified staff that
they would not be able to meet the order schedule and
closure dates of Directives Nos. 2(c), 2 (d), and 2(e) due to
delays in receiving the required local permits from the City
of Carlsbad (City). SDG&E stated that they requested a
determination of this issue in August 1988. In January
1989, the City determined that an amendment was required,
but the amendment was not approved by the City until July
.~«WJ- *? ',-_••
Addendum No. 1 to -2- June 4, 1990
CtD Order No. 88-81
SDG&E Encina Plant
1989. 8DG&E has requested an extension of the remaining
applicable compliance dates in the Cease and Desist order
compliance schedule due to these delays.
4. By letter dated April 10, 1990, the City confirmed that the
construction of above-ground storage tanks to replace the
existing surface impoundments required an amendment of the
specific plan regulating the Encina Power Plant. The
amendment was not approved by the City until July 1989.
5. This enforcement action is exempt from the provisions of the
California Environmental Quality Act (Public Resources Code,
Section 21000 et. seq.) in accordance with Section 15321,
Chapter 3, Title 14, California Code of Regulations.
IT IS HEREBY ORDERED, that Directive No. 2(c), (d) , and (e) of
Cease and Desist Order No. 88-81 is revised as follows:
Compliance Report Due
1. Task Date Date
(c) Cease discharge of liquid 6/30/91 7/15/91
hazardous waste or hazardous
waste containing free liquids
into existing surface
impoundments.
(d) Initiate closure and cleanup. 7/01/91 8/15/91
(e) Finish closure and cleanup. 7/01/92 8/15/92
Ordered by:.
Dated: June 4, 1990
JPAienc C&D.amd
Arthur L. Coe
Acting Executive Officer
SDG&E C&D Add. Transmittal -2- June 14, 1990
Encina Power Plant
Enclosure
cc: Mr. Fred Jacobsen, Environmental Analyst, SDG&E
Mr. James Parsons, TPCA Program Manager, State Water
Resources Control Board, Division of Clean Water Programs,
Sacramento, California
Ms. Sheila Vassey, Senior Staff Counsel, Office of Chief
Counsel, State Water Resources Control Board, Sacramento,
California
San Diego Gas & Electric
P.O. BOX 1831 • SAN DIEGO, CA 92112 • 619/696-2000
April 2, 1991 FILENO.
Ms. Adrienne Landers
City of Carlsbad
2075 Las Palmas Drive
San Diego, CA 92009-4859
SUBJECT: WASTEWATER PONDS REMOVAL: ENVIRONMENTAL REVIEW
Dear Dee:
This letter follows the Planning Department's review and
concurrence that project environmental review per CEQA is the
responsibility of the California Regional Water Quality Control
Board (RWQCB). Per your request, copies of the Waste Discharge
Requirements (Order No. 88-80), Monitoring and Reporting Program
No. 88-80, Cease & Desist Order 88-81 plus an addendum, and the
Encina Power Plant Wastewater Ponds Closure Plan as approved by
the Board are attached for your files. The RWQCB will notice the
City of Carlsbad when it takes action to certify that the closure
process has been completed in compliance with the approved
closure plan and amends or rescinds the existing water discharge
requirement and cease and desist order.
A coastal development permit is required for the removal of
the wastewater ponds. This permit requirement will be processed
concurrently with the city grading permit requirement. Attached
is the LOCAL AGENCY REVIEW FORM that must be completed by the
city and submitted as part of the coastal permit application
filing. Your attention to the completion of the form and its
return to my attention would be greatly appreciated.
Please call me at 696-2410 if you have questions about this
matter.
David S. Siino
Senior Land Planner
DSS:kmd
Attachments
cc: Paul O'Neal, SDG&E
John Anderson, RWQCB
[LANDALTR.D02]
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD
SAN DIEGO REGION
MONITORING AND REPORTING PROGRAM NO. 88-80
FOR
SAN DIEGO GAS & ELECTRIC COMPANY
ENCINA POWER PLANT
CLASS I SURFACE IMPOUNDMENTS
SAN DIEGO COUNTY
Site Location: Section 18, T12S, R4W, SBB&M
A. MONITORING PROVISIONS
1. Samples and measurements taken as required herein shall be representative of the
volume and nature of the monitored discharge. All samples shall be taken at the
monitoring points specified in this Order. Monitoring points shall not be changed
without notification to and the approval of the Executive Officer.
2. The discharger shall develop and follow a ground-water monitoring program which
includes consistent and appropriate sampling and analytical procedures that accurately
measure indicator parameters and waste constituents and would provide a reliable
indication of ground and surface water quality.
3. Sample collection, storage, and analyses shall be performed according to the most
recent version of "Test Methods for Evaluating Solid Waste" (EPA/SW-846), "Methods
for Chemical Analysis of Water and Waste" (EPA/600/4-79-020), "Methods for Organic
Chemical Analysis of Municipal and Industrial Wastewater" (EPA-600/4-82-057), and/or
"Standard Methods for the Examination of Water and Wastewater."
4. All analyses shall be preformed in a laboratory certified to perform such analyses by
the California Department of Health Services or a laboratory approved by the
Executive Officer. The director of the laboratory whose name appears on the
certification shall supervise all analytical work in his/her laboratory and shall sign
all reports of such work submitted to the Regional Board.
5. Monitoring results must be reported on discharge monitoring report forms approved
by the Executive Officer.
6. The discharger shall retain records of all monitoring information, including all
calibration and maintenance records, copies of all reports required by this Order, and
records of all data used to complete the application for this Order. Records shall be
maintained for a minimum of five years from the date of the sample, measurement,
report, or application. This period may be extended during the course of any
unresolved litigation regarding this discharge or when requested by the Regional
Board Executive Officer.
7. Records of monitoring information shall include:
(a). The date, exact place, and time of sampling or measurements;
(b). The individual(s) who performed the sampling or measurements;
(c). The date(s) analyses were performed;
ORDER NO. 88-80 -2-
(d). The individual(s) who performed the analyses;
(e). The analytical techniques or method used; and
(f). The results of such analyses.
8. Calculations for all limitations which require averaging of measurements shall utilize
an arithmetic mean unless otherwise specified by the Executive Officer or in this
Order.
9. All monitoring instruments and devices used by the discharger to fulfill the
prescribed monitoring program shall be properly maintained and calibrated as
necessary to ensure their continued accuracy.
10. The discharger shall have, and implement, an acceptable written quality
assurance/quality control (QA/QC) plan for laboratory analyses. An annual report
shall be submitted by February 28 of each year which summarizes the QA/QC
activities for the previous year. Duplicate chemical analyses must be conducted on a
minimum of ten percent of the samples or at least one sample per quarter, whichever
is greater. A similar frequency shall be maintained for analyzing spiked samples.
11. The monitoring reports shall be signed by an authorized person as required by
Reporting Program E.I.
12. A composite sample is defined as a combination of at least 8 sample aliquots of at
least JOO milHliters, collected at periodic intervals during the operating hours of the
facility over a 24-hour period. The composite must be flow proportional; either the
time interval between each aliquot or the volume of each aliquot must be
proportional to either the stream flow at the time of sampling or the total stream
flow since the collection of the previous aliquot. Aliquots may be collected manually
or automatically.
13. A grab sample is an individual sample of at least 100 milliliters collected at a
randomly selected time over a period not exceeding 15 minutes.
B. GROUND-WATER MONITORING
1. The discharger shall continue a detection and background monitoring program for one
year (four quarters). The Board may require additional monitoring following the
completion and evaluation of this data. Surface water monitoring is established in
"Monitoring and Reporting Program No. 85-10" pursuant to Waste Discharge
Requirements Order No. 85-10 (NPDES Permit No. CA0001350).
2. Ground-water sampling for the detection and background ground-water monitoring
program shall include the constituents listed under interim Water Quality Protection
Standards. C.I. of Board Order No. 88-80 and shall include general ground-water
chemistry. The general ground-water chemical constituents shall include calcium
(Ca), magnesium (Mg). sodium (Na). potassium (K). chloride (CD, sulfate (804),
carbonate (CO3). and bicarbonate (HCO3). The quarterly monitoring reports shall
include a cation, anion balance for each well.
ORDER NO. 88-80 -3-
3. New monitoring weiis shall be designed and certified as adequate pursuant to Section
2555 of Subchapter 15 by a registered geologist or a registered civil engineer in the
State of California.
4. All monitoring wells shall be constructed in a manner that maintains the integrity of
the drill hole and prevents cross-contamination of saturated zones. The casing shall
be a minimum of two inches in diameter. The annular space shall be packed with
appropriate filter material that is sized to match the formation. The annular space
above the screened depth shall be appropriately sealed to prevent contamination of
samples and ground water from surface pollution. The well shall be adequately
developed to prevent the movement of sediment into the casing and to produce the
highest yield possible from the formation. Each well shall be marked permanently so
as to readily identify it and shall have a reference point tied into mean sea level
elevation by a licensed surveyor. All monitoring wells shall be logged during drilling
under the direct supervision of a California registered geologist. All monitoring well
logs submitted to the Board shall be signed by the registered geologist. All
monitoring well logs shall be filed with the Department of Water Resources (DW'R) on
forms provided by DWR, pursuant to Water Code Section 13751. Soil shall be
described according to the Unified Soil Classification System. Copies of the logs
and as-built specifications of the wells shall be submitted to the Regional Board.
5. Prior to sampling the wells, the presence of a floating immiscible layer in all wells
shall be determined at the beginning of each sampling event. If an immiscible layer
is found, the Regional Board shall be notified within 24 hours.
6. Prior to pumping the wells for sampling, the static water level shall be measured in
each well.
7. Prior to sampling the wells, the water standing in the casing shall be pumped using a
step-down purging method until the water chemistry has stabilized with respect to
pH and specific conductance. Water chemistry can be considered stable when in-line
specific conductance and pH readings are within +_10% and +_0.1 pH units respectively
over 2 successive well volumes. Samples shall be obtained that are representative of
the fresh aquifer formation water.
8. After purging, if 80% recovery of the initial water level exceeds three hours, a
sample should be collected as soon as the water level is sufficient to recover a
representative sample.
9. For each parameter specified, the discharger shall calculate the arithmetic mean and
variance of the samples obtained yearly and shall be included in the annual report.
C. REPORTING PROGRAM AND SCHEDULE
1. A letter of transmittal shall accompany each submitted monitoring report. The letter
should discuss the essential points in each monitoring report. Such a letter shall
include a discussion of any significant findings and violation(s) of requirements found
during the monitoring period and actions taken or planned for correcting the
violation(s). If the discharger has previously submitted a detailed time schedule for
ORDER NO. 88-80 -4-
correcting violation(s) a reference to the correspondence transmitting such schedule
will suffice. If no violations have occurred in the last monitoring period, it shall be
stated in the letter of transmittal. Monitoring reports and the letter of transmittal
shall be signed by a principal executive officer at the level of vice president or
his/her duly authorized representative, if such representative is responsible for the
overall operation of the facility from which the discharge originates. The letter
shall contain a statement by the official, under penalty of perjury, that to the best
of the signer's knowledge the report is true, complete, and correct.
2. Field logs for each ground-water well shall be included in the ground-water
monitoring reports. The information contained in these logs shall include: the name
of the person actually taking the sample, well number, date, time of sampling,
method of purging and sampling (if a pump is used, include, the type of pump used,
pump placement, and pumping rate), date each well was purged, well recovery time,
method of disposal of the purged water, an estimate of volume of water purged from
each well, the results of all field analyses, the method of monitoring the field
parameters, sampling procedure, depth to ground water, method of measuring the
water level, number of field blanks, presence of travel blanks, well number where
duplicate samples are taken, type of sample containers and preservatives, any
observations of the quality of the sample water (color, odors, immiscible phases,
etc.), chain of custody record, and any problems encountered during sampling.
3. All laboratory reports shall include QA/QC procedures. This shall include recovery
rates, results from blanks, spikes, and duplicate samples. An explanation for any
recovery rate which is less than the standard recovery rate for that particular
constituent shall be included.
4. The discharger shall submit a compliance evaluation summary of the ground-water
chemical data obtained for the quarter. The summary shall contain a table which
includes the following information:
(a). Monitoring parameters;
(b). Detection limit of monitoring equipment;
(c). Water quality protection standards for each parameter;
(d). Average concentration for each parameter over the previous four quarterly
monitoring events;
(e). Measured concentrations found in the current sampling event; and
(f). Whether a significant difference was found for each parameter.
The measured concentrations shall be reported with a "<" symbol only if the value
listed after the symbol is the detection limit achieved by the laboratory.
5. The discharger shall submit an annual report summarizing the previous year's ground-
water monitoring results. This report shall include the following:
(a). A summary of the QA/QC activities for the previous year(s);
(b). A summary of the previous year's water quality data results, which shall include
a graphical representation of the data.
ORDER NO. 88-80 -5-
The discharger shall submit a graphical illustration of the direction of ground-water
flow beneath the surface impoundments. The time of day at which each well's water
level is determined shall be included with the graphical presentation of the direction
of ground-water flow. Any wells subject to tidal influence should include tide tables
for that sampling period and a determination of in-coming or out-going tides.
The monitoring reports shall be submitted to the Executive Officer in accordance
with the following schedule:
Report Report Period Due Date
Quarterly January, February, March
April, May, June
July, August, September
October, November, December
Annual January - December
April 30
July 30
October 30
January 30
February 28
Forward monitoring reports to:
California Regional Water Quality Control Board
San Diego Region
9771 Clairemont Mesa Boulevard, Suite B
San Diego, CA 92124-1331
Ordered by:
LADIN H. DELANEY
Executive Officer
-5 rn
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD
SAN DIEGO REGION
ORDER NO. 88-80
WASTE DISCHARGE REQUIREMENTS
FOR
SAN DIEGO GAS & ELECTRIC COMPANY
ENCINA POWER PLANT
CLASS I SLTRFACE IMPOUNDMENTS
SAN DIEGO COUNTY
The California Regional Water Quality Control Board (hereinafter referred to as the Board),
San Diego Region, finds that: ••••
1. Mr. Gary D. Cotton, Senior Vice President of Engineering & Operations for San Diego
Gas & Electric Company (hereinafter referred to as the discharger), P.O. Box 1831, San
Diego, California, 92112, submitted a complete Report of Waste Discharge dated October
7, 1987 for operation of six surface impoundments at the Encina Power Plant. The report
includes a hydrogeologic assessment report (HAR), dated December 31, 1985, pursuant to
provisions of the Toxic Pits Cleanup Act of 1984 (TPCA), Section 25208 of the California
Health and Safety Code (CHSC) and additional information pursuant to Subchapter 15,
Chapter 3, Title 23 of the California Code of Regulations (Subchapter 15).
2. The discharger owns and operates a power plant at 4600 Carlsbad Boulevard, in the
southwest sector of the City of Carlsbad, California, adjacent to and immediately
south of the Agua Hedionda Lagoon on the Pacific Ocean. The power plant is in Section
18, T12S, R4W, SBB&M. A site map is shown in Attachment A appended hereto as a part
of this Order.
3. The Encina Power Plant has five steam turbine generators and one gas turbine generator.
All five units burn gas or fuel oil depending on economic conditions. All units operate
independently, or in conjunction with, one another; but share the once-through cooling
water system. The table below summarizes each unit's capacity and start up date.
Unit Date on Line Capacity
1 1954 105 MW
2 1956 104 MW
3 1958 110MW
4 1973 287 MW
5 1978 315 MW
Gas Turbine 1968 20 MW
Total Plant Capacity 941 MW
The total rated net generating capability of the Encina Power Plant is 941 megawatts
(MW). and there are no pians for major modifications in the capacity of the plant in the
near future.
ORDER NO. 88-80 -2-
4. At full capacity the total estimated water usage at the Encina Power Plant is 858.7
million gallons per day (MGD) of which 99.81 percent is once through cooling water
obtained from the Pacific Ocean. The balance of the service water is obtained from the
municipal water supply. Seepage and ground-water pumping account for over 1.6 MGD in
additional plant flow. Cooling water is withdrawn from the Pacific Ocean via the Agua
Hedionda Lagoon. After passing through the intake structure, trash racks and traveling
screens; the water is pumped through the condensers. The amount of cooling water
required is dependent upon the number of units in operation. The heated water is
discharged to the Pacific Ocean after passing through a discharge pond.
5. A breakdown of the estimated maximum wastewater discharged to the surface
impoundments at the Encina Power Plant is tabulated below.
How
Nonhazardous Waste Stream (Gallons Per Day)
(a) Low Volume Wastewater 125,000
(1) Condensate boiler blowdown
(2) Evaporator blowdown
(3) Sample drains
(4) Floor drains
(5) Demineralizer
(6) Softeners
(7) Dealkalizer
(8) Condenser cleaning
(9) Reverse osmosis
(10) Purged ground water from
monitoring wells
(11) Treated low volume waste
Estimated Annual Maximum
Hazardous Waste Stream Volume in gallons *
(a) Metal Cleaning Wastewater 5,375,000
(1) Boiler chemical cleaning
(2) Hypochlorinator chemical cleaning
(3) Evaporator chemical cleaning
(4) Air heater wash
(5) Boiler fireside wash
(6) Condenser chemical cleaning
(7) Reverse osmosis cleaning
(8) Treated metal cleaning waste **
* Based on two boiler chemical cleanings per year and three boiler fireside washes per unit
per year per facility.
** Occasionally, the treated metal cleaning wastewater contains hazardous waste constituents
and will be handled as a hazardous waste.
ORDER NO. 88-80 -3-
6. The Board issued "Waste Discharge Requirements For San Diego Gas & Electric Company,
Encina Power Plant" for discharge to the Pacific Ocean under the National Pollutant
Discharge Elimination System pursuant to Section 402 of the Clean Water Act. Order No.
85-10 (NPDES Permit No. CA0001350) was reissued January 28, 1985.
7. The Encina Power Plant has six surface impoundments which are used for temporary
storage of wastewater. Wastewaters which require treatment are treated in an adjacent
physical/chemical treatment facility. The treated wastewater is then discharged to the
Pacific Ocean in accordance with Order No. 85-10 (see Finding No. 6).
8. The six surface impoundments at the power plant were constructed in 1978 and are
located in two separate areas. Impoundments Nos. 1, 2, 3, and 4 are located north of
the power plant. From west to east, they consist of two low-volume waste impoundments
(Nos. 1 and 2, with a maximum storage capacity of 300,000 and 590,000 gallons each
respectively) and two metai-cleaning waste impoundments (Nos. 3 and 4, with a maximum
storage capacity of 750,000 and 330,000 gallons each respectively). Treated wastewater
impoundments (Nos. 5 and 6, with a maximum storage capacity of 220,000 and 270,000
gallons each respectively) are located northeast of the plant, approximately 540 feet from
the low-volume and metal-cleaning waste impoundments. Impoundment No. 1 is
approximately 60 feet south of Agua Hedionda Lagoon.
9. Boiler fireside washes are needed to remove soot and accumulated combustion by-
products from metal surfaces in order to maintain efficient heat transfer. Frequency
again depends on the fuel being burned. These washes are accomplished by spraying
high-pressure water against the surfaces to be cleaned. The wastewaters generated
contain an assortment of dissolved and suspended solids with loadings and constituents
dependent upon the fuel used.
10. Metal cleaning waste waters undergo neutralization, floccuiation, and chemical
precipitation at an on-site waste water treatment plant. For low volume wastes that are
treated, the facility provides physical-chemical treatment (neutralization, floccuiation, and
chemical precipitation) if required; otherwise the waste is discharged from the primary
treatment tank, or the physical-chemical treatment plant to the condenser cooling water
flow.
11. The power plant site area consists of low, rolling hills of Eocene sediments bounded on
the west by a coastal plain where the Eocene sediments are overlain by Pleistocene and
Holocene sediments. Fill soils consist of silty to clayey sands and range in thickness from
6 to 32 feet. Lagoonal deposits underlie the fill (surface impoundments 1-4 area) and
consist of silty sands and sands with occasional ciayey sand imerbeds. The lagoonal
sediments range in thickness from 0 to about 65 feet. Underlying the lagoonal deposits is
the Santiago Formation which consist of very dense, silty to clayey sands with occasional
clay interbeds. Beneath the fill (under surface impoundments 5 and 6) is the Pleistocene
coastal terrace deposits. These terrace deposits consist of medium dense sands with
intermittent gravels. This unit is up to 15 feet thick.
ORDER NO. 88-80 -4-
12. The surface impoundments are subject to regulations under the State Board's land
disposal regulations (Subchapter 15) and TPCA. On December 21, 1987, the Regional
Board adopted Order No. 87-137, which prescribed waste discharge requirements for the 6
surface impoundments. The requirements contain specifications and provisions to bring the
discharger into full compliance with Subchapter 15 and TPCA.
13. Board Order No. 87-137 also granted the discharger several exemptions from the
requirements of TPCA which would enable the discharger to retrofit its present surface
impoundments and to continue uninterrupted operation. In particular, Order No. 87-137
granted the discharger an exemption from the TPCA prohibition against discharge of
liquid hazardous waste or hazardous waste containing free liquids into a surface
impoundment after June 30, 1988 if the impoundment is located within 1/2 mile
upgradient of a drinking water source. Order No. 87-137 also granted the discharger a
temporary exemption, until December 21, 1988, from the TPCA prohibition against
discharge of liquid hazardous wastes or hazardous wastes containing free liquids into a
surface impoundment.
14. Concurrently with adoption of Order No. 87-137, the Board issued Cease and Desist Order
No. 87-138 pursuant to Section 13301 of the California Water Code, requiring the
owner/operator to retrofit the surface impoundments and to clean up any pollution which
had occurred.
15. Subsequent to adoption of Order Nos. 87-137 and 87-138, the discharger decided to close
the existing surface impoundments rather than upgrade the impoundments to meet TPCA
and Subchapter 15 requirements. By letter dated May 9, 1988, the discharger reported to
staff its intent to replace the impoundments with above-ground tanks (for the metal
cleaning and treated wastes) and an in-line treatment system (for the low volume
nonhazardous wastes). This decision was based on a cost and feasibility analysis of
retrofitting the surface impoundments to current standards, notably the seismic design
criteria as prescribed in Subchapter 15.
16. SDG&E's decision caused several discharge specifications contained in Order No. 87-137
to become obsolete. Therefore, Order No. 88-80 reflects necessary modifications to Order
No. 87-137. "Waste Discharge Requirements for San Diego Gas & Electric Company,
Encina Power Plant, Class I Surface Impoundments, San Diego".
17. Order No. 88-80 rescinds the three exemptions granted by Order No. 87-137 and
prescribes standards for closure of the impoundments. In addition, Order No. 88-80
implements TPCA prohibitions contained in CHSC Sections 25208.4(a) and (cX2) against the
discharge of hazardous and restricted hazardous wastes into surface impoundments.
18. The discharger intends to discharge low volume nonhazardous wastes into some of the
impoundments after December 1988 for temporary storage until the in-line treatment
system is operational.
19. The discharger has demonstrated that all sludges have been removed from all of the
impoundments and that all of the impoundment liners have been tested and are
nonhazardous.
ORDER NO. 88-80 -5-
20. Under TPCA, exemptions from the discharge prohibitions contained in CHSC Sections
25208.4(a) and (cX2) may be granted by a Regional Board only if a surface impoundment
complies with TPCA requirements regarding liners, leachate collection and ground-water
monitoring. A temporary exemption from the liner requirements may-be -granted in some.
cases, under Section 25208.5(c), to enable a discharger to bring a facility into compliance
with these requirements. Since the discharger in this case no longer intends to retrofit
its impoundments, the basis for the exemptions granted in Order No. 87-137 are no longer
applicable.
21. Additionally, a revised Cease and Desist Order No. 88-81 has been drafted for adoption
by the Regional Board. Cease and Desist Order No. 88-81 replaces Cease and Desist
Order No. 87-138.
22. The discharger has submitted results from four quarters of ground-water monitoring data.
The first two quarters of data are results of analyses performed by a contract laboratory
and the last two quarters of data are results of analyses performed by the discharger's
laboratory. There are significant discrepancies between the two sets of data. Therefore,
the Board has concluded that interim water quality protection standards will be established
until additional ground-water monitoring results have been evaluated. The Board will
require the discharger to continue background and detection monitoring for another year.
At the end of this period, the Board will establish final water quality protection
standards, based on the additional information, for the facility. In the interim, the
discharger will not be required to implement or initiate verification monitoring until the
final water quality protection standards have been established.
23. The Comprehensive Water Quality Control Plan Report, San Diego Basin (9) (Basin Plan)
was adopted by this Regional Board on March 17, 1975; approved by the State Water
Resources Control Board (State Board) on March 20, 1975; with subsequent updates by the
Regional Board which were also approved by the State Board. The Basin Plan establishes
water quality objectives for the San Diego Basin.
24. The Basin Plan established the following as potential and existing beneficial uses for the_
Agua Hedionda Lagoon coastal area;
(a). Industrial Service Supply
(b). Water Contact Recreation
(c). Non-Contact Water Recreation
(d). Ocean Commercial and Sport Fishing
(e). Saline Water Habitat
(f). Preservation of Rare and Endangered Species
(g). Marine Habitat
(h). Shellfish Harvesting
25. This facility is exempt from provisions of the California Environmental Quality Act
(Section 15301, Title 14 of the California Code of Regulations) as an existing facility
with minor modifications and having no anticipated expansion of use. The Regional
Board finds that no adverse water quality impacts will result if the discharger complies
with the terms of this Order.
ORDER NO. 88-SO -6-
26. The Regional Board has notified the discharger and all known interested agencies and
persons of its intent to prescribe waste discharge requirements for this discharge.
27. The Regional Board has, in a public meeting, heard and considered all comments
pertaining to the discharge.
IT IS HEREBY ORDERED, based on the record, that the Regional Board take the following
actions:
1. The following exemptions, which were granted on December 21, 1987, are hereby
rescinded upon adoption of this Order:
(a). Exemption from Section 25208.4(a) pursuant to Section 25208.4(b)(l) for the continued
discharge of liquid hazardous wastes or hazardous wastes containing free liquids into
surface impoundments Nos. 1 through 6 which are within one-half mile upgradient
from a potential source of drinking water.
(b). Exemption from Section 25208.4(c)(2) pursuant to Section 25208.16(a) as described in
Finding No. 31 of Order No. 87-137 for surface impoundments Nos. 1 through 6.
(c). The temporary exemption from Section 25208.5(a) for up to one year from the
effective date of Order No. 87-137 (December 21, 1988), for the sole purpose of
bringing surface impoundments Nos. 1 through 6 into compliance with Section
25208.5(a).
IT IS FURTHER ORDERED, that San Diego Gas & Electric Company shall comply with the
following:
A. PROHIBITIONS
1. Neither the treatment nor the discharge of wastes shall create a pollution or a
nuisance as defined in Section 13050, Division 7 of the California Water Code.
2. The discharge of liquid hazardous wastes or hazardous wastes containing free liquids
to the existing surface impoundments after June 30, 1988 is prohibited.
3. The discharge of restricted hazardous waste into the surface impoundments is
prohibited.
4. The discharge of any low volume nonhazardous wastes or waste constituents from the
surface impoundments or associated piping to any surface waters of the State or to
surface drainage courses is prohibited unless the discharge is permitted under the
National Pollutant Discharge Elimination System by issuance of Waste Discharge
Requirements by the Regional Board.
ORDER NO. 88-80 -7-
B. DISCHARGE SPECIFICATIONS
1. Prior to final closure of the surface impoundments, the discharger shall submit a
closure and post-closure maintenance plan for approval by the Executive Officer.
The plan shall provide for continued compliance with all applicable standards
pursuant to Subchapter 15 and future revisions thereto, throughout the closure and
post-closure maintenance period.
2. The discharge of any low volume nonhazardous wastes or waste constituents from the
surface impoundments or associated piping to ground waters of the State or to the
vadose zone surrounding the surface impoundments shall not cause a pollution,
nuisance, or cause the Basin Plan objectives to be exceeded.
3. The discharge of low volume nonhazardous wastes to the existing surface
impoundments shall be continued only until the proposed in-line low volume waste
treatment system is complete and functional. Upon completion of the in-line
treatment system, discharge to the impoundments shall terminate and the discharger
shall notify the Executive Officer, in writing, to that effect.
C. WATER QUALITY PROTECTION STANDARDS
1. At present, interim water quality protection standards have been developed for
indicator parameters and for waste constituents which are reasonably expected to be
in or derived from wastes discharged into the surface impoundments. They are based
on the current background water quality. The interim water quality protection
standards include the following:
Water Quality Protection
Constituents Standard (mg'!)
pH (pH Units) 7.0 - 8.3
Arsenic (As) 0.008
Cadmium (Cd) 0.1
Copper (Cu) 0.3
Chromium (Total Cr) 0.16
Lead (Pb) 0.2
Molybdenum (Mo) 0.37
Nickel (Ni) 1.6
Vanadium (V) 0.1
Zinc (Zn) 0.41
Oil & Grease 34
2. The discharger shall continue a ground-water detection and background monitoring
program at points of compliance for one year (four quarters) as set forth in
"Monitoring and Reporting Program No. 88-80."
3. Until final water quality protection standards are established, pursuant to C.I. of this
Order, the discharger shall not be required to implement or initiate a verification
monitoring program pursuant to Subchapter 15.
ORDER NO. 88-80 -8-
D. PROVISIONS
1. Ground-water monitoring shall apply during the active life of the surface
impoundments (including the closure period unless all waste, waste residues,
contaminated containment system components, and contaminated geologic materials
have been removed or decontaminated at closure).
2. The discharger shall comply with "Monitoring and Reporting Program No. 88-80" and
future revisions thereto, as specified by the Executive Officer. Monitoring results
shall be reported at the intervals specified in Monitoring and Reporting Program No.
88-80.
3. Prior to any change in ownership of these facilities/operations, the discharger shall
transmit a copy of this Order to the succeeding owner/operator, and forward a copy
of the transmittal letter to this Board.
4. This Qrder does not authorize violation of any federal, state, or local laws or
regulations.
5. The discharger shall maintain a copy of this Order at the site to be available at all
times to site operating personnel.
6. The discharger shall notify the Regional Board (in writing) seven days prior to any
vital power plant cleaning operation that could possibly generate restricted hazardous
waste.
E. NOTIFICATIONS
1. These requirements have not been officially reviewed by the United States
Environmental Protection Agency and are not issued pursuant to Section 402 of the
Clean Water Act.
2. The California Water Code provides that any person who intentionally or negligently
violates any waste discharge requirements issued, reissued, or amended by this
Regional Board is subject to a civil monetary remedy of up to 20 dollars per gallon
of waste discharged or, if a cleanup and abatement order is issued, up to 15,000
dollars per day of violation or some combination thereof.
3. The California Water Code provides that any person failing or refusing to furnish
technical or monitoring program reports, as required under this Order, or falsifying
any information provided in the monitoring reports is guilty of a misdemeanor.
4. The requirements prescribed by this Order supersede the requirements prescribed by
Board Order No. 87-137. Order No. 87-137 is hereby rescinded upon adoption of this
Order.
ORDER NO. 88-80 -9-
I, Ladin H. Delaney, Executive Officer, do hereby certify, the foregoing is a full, true, and
correct copy of an Order adopted by the California Regional Water Quality Control Board,
on August 29, 1988.
LADIN H. DELANEY
Executive Officer
CLOSURE PLAN
ENCINA POWER PLANT
Prepared for:
SAN DIEGO GAS & ELECTRIC COMPANY
CARLSBAD, CALIFORNIA
Prepared by:
MITTELHAUSER CORPORATION
LAGUNA HILLS, CALIFORNIA
/V1ITTELH>1USER Lcorpora hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RJ
TABLE OF CONTENTS
Page No,
1. 0 INTRODUCTION 1-1
2.0 FACILITY INFORMATION 2-1
2.1 General Facility Description 2-1
2.2 Waste Management Unit Being Closed 2-1
2 . 3 Owner/Operator Information 2-3
2 . 4 Power Plant Contact 2-3
3 . 0 WASTE MANAGEMENT FACILITY 3-1
3.1 Impoundment Design 3-1
3.1.1 Impoundment Operation 3-5
3.2 Maximum Extent of Operations and Maximum
Inventory 3-9
3.3 Waste Identification 3-9
4 . 0 CLOSURE PROCEDURES 4-1
4 .1 Closure Performance Standards 4-1
4 . 2 Site Cleanup Strategy 4-1
4.2.1 Introduction 4-1
4.2.2 Analysis Parameters 4-2
4.2.3 Cleanup Levels 4-6
4 . 3 Approach to Closure 4-8
4.3.1 Existing Analytical Data 4-9
4.3.2 Summary of Closure Activities 4-12
4 . 4 Final Closure Activities 4-15
4.5 Schedule for Closure 4-18
4.6 Post-Closure Plan 4-19
5.0 SAMPLE CONTROL 5-1
6. 0 DECONTAMINATION OF FACILITY EQUIPMENT 6-1
7.0 CLOSURE COST ESTIMATE 7-1
7.1 Contingent Closure and Post-Closure Plan
and Cost Estimate 7-3
8 . 0 FINANCIAL ASSURANCE AND LIABILITY COVERAGE 8-1
8.1 Financial Assurance for Closure/Post-Closure 8-1
8.2 Liability Coverage for Sudden and Non-Sudden
Accidental Occurrence 8-2
(i)
/V1ITTELH/1USER vcorporation
SDG&E
Encina Power Plant
Closure Plan
December 1988
Rev: 0
P1080RJ
LIST OF TABLES AND FIGURES
Figures
2-1
3-1
3-2
3-3
3-4
4-5-1
Tables
3-1
3-2
3-3
3-4
3-5
Page No,
Site Location Map 2-2
Site Plan 3-2
Plan View of Surface Impoundments 3-3
Schematic Cross Section of Typical Impoundment... 3-5
Groundwater Subdrain and Leachate Collection
Systems 3-7
Proposed Locations of Soil Borings for LVW 1
and 2 4-5-5
Impoundment Characteristics 3-8
Chemical Constituents of Metal-Cleaning
Operations 3-12
Chemical Constituents of Low-Volume Waste 3-13
Impoundment Waste Stream Characteristics - 1985.. 3-14
Impoundment Waste Characteristics - 1986 3-15
LIST OF ATTACHMENTS
4-1 Analytical Data from RI
4-2 Establishment of Background Levels
4-3 Deionized Water Waste Extraction Test Rationale
4-4 Closure Step Decision Diagram
4-5 Sampling and Analysis Plan
4-6 Letter Regarding Remedial Investigation Report
8-1 Draft Letter by Financial Officer
8-2 Special Report from SDG&E's Independent Certified
Accountant
8-3 Opinion of Independent Certified Public Accountants
8-4 Fourth Quarter of 1987 Financial Summary
(ii)
/MITTELKMUSERcorpora hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RA
SECTION 1.0
INTRODUCTION
/HITTELH/4USER t^corporation
SDG&E 1-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RA
1.0 INTRODUCTION
San Diego Gas and Electric Company (SDG&E) hereby
submits this Closure Plan for the Wastewater Ponds located at the
Encina Power Plant. The Plan is submitted to California San Diego
Regional Water Quality Control Board (RWQCB) and the California
Department of Health Services (DHS).
This Closure Plan meets the requirements of 40 CFR265
for an Interim Status RCRA facility and of Title 22 and Title 23
of the California Code of Regulations (CCR). The plant will
continue operating the wastewater ponds and the groundwater
monitoring system under Title 23 until final closure is approved
by the regulatory agencies.
The closure approach presented in Section 4.0 has been
developed on data presented to the RWQCB in two reports. These
reports are:
1. Hydrogeologic Assessment Report (HAR) for the Encina
Power Plant, September 1986, and
2. Remedial Investigation (RI) for the Encina Power
Plant/ February 1988.
/MITTELHMUSER .corpora hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RB
SECTION 2.0
FACILITY INFORMATION
/MITTELH/1USER t.corporation
SDG&E 2-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RB
2.0 FACILITY INFORMATION
2.1 GENERAL FACILITY DESCRIPTION
San Diego Gas and Electric is a privately owned public
utility providing electric service in SDG&E's California service
territory. Encina Power Plant is owned and operated by the San
Diego Gas and Electric Company (SDG&E). The plant is located in
Carlsbad, California; on the coast line of the Pacific Ocean. A
site location map is presented in Figure 2-1.
2.2 WASTE MANAGEMENT UNIT BEING CLOSED
This Closure Plan is for six surface impoundments
located at the SDG&E Encina Power Plant. The surface impoundments
are used for the temporary collection of wastewater prior to
treatment and/or discharge to the Pacific Ocean in accordance with
NPDES Permit Number CA0001350. Sediment that accumulates in the
impoundments is analyzed and disposed of in accordance with
Federal and State regulations.
SDG&E has decided to replace the existing six surface
impoundments with a new wastewater system consisting of
aboveground tanks. When the new system is in operation, SDG&E
will implement this closure plan.
Oceanside
SDG&E
ENCINA
POWER PLANT
Cardiff by the Sea
N
GRAPHIC SCALE (miles)
Del Mar
Pacific
Ocean
3AA
'KYM
**" 12/oe/aa
"""AS SHOWN
*•"• "PIDBO
FIGURE 2-1
SITE LOCATION MAP
soue ENONA POVEK PLANT
1080-00-006
/HITTELH/IUSERcorporation
SDG&E 2-3 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RB
2.3 OWNER/OPERATOR INFORMATION
The name, address and telephone number for the owner/
operator of the facility, the type of facility and SIC code are as
follows:
Owner/Operator: San Diego Gas and Electric Company
101 Ash Street
P. 0. Box 1831
San Diego, CA 92112
(619) 696-2000
Facility: San Diego Gas and Electric Company
Encina Power Plant
4600 Carlsbad Blvd.
Carlsbad, CA 92008
(619) 235-7777
Type of Facility: Electric Power Generation
- SIC: 4911
2.4 CONTACT
The SDG&E contact with regard to the Closure Plan is:
Name: Mr. Lee R. McDonald, P.E.
Environmental Programs
Administrator
- Address: 101 Ash Street
P. 0. Box 1831
San Diego, California 92112
- Phone: (619) 696-4391
/MITTELH>1USER tcorpora hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
SECTION 3.0
WASTE MANAGEMENT FACILITY
/MITTELH/1USERcorporation
SDG&E 3-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
3.0 WASTE MANAGEMENT FACILITY
The six surface impoundments at the Encina Power Plant
are grouped in two separate areas as shown on the site plan,
Figure 3-1. Impoundments No. 1, 2, 3 and 4 are located north of
power plant. From west to east, there are two low-volume waste
impoundments (Nos. 1 and 2) and two metal-cleaning waste
impoundments (Nos. 3 and 4) . Treated wastewater impoundments,
Nos. 5 and 6, are located adjacent to the water treatment plant
which is located approximately 540 feet southeast from the other
impoundment cluster. The impoundments are shown on Figure 3-2.
3.1 IMPOUNDMENT DESIGN
The surface impoundments were constructed in 1978. The
low-volume and metal-cleaning waste impoundments (Nos. 1 through
4) are built on an engineered pad of compacted fill. The
elevation of the top of the impoundments is approximately +27 feet
mean sea level (MSL) and the base elevation is approximately +6 to
+17 feet MSL. The elevation of the lower liners of the
impoundments vary between approximately +10 to +14 feet MSL.
Impoundments No. 5 and 6 are also on an engineered fill pad with a
crest elevation of approximately +38 feet MSL. The lower liner of
these impoundments is at an elevation of approximately +30 feet
MSL. The west face of the berm at Impoundments No. 5 and 6 is
covered by concrete, and slopes steeply toward a drainage channel.
AGUA HEDIONDA
LAGOON
LOW-VOLUME WASTE
IMPOUNDMENTS
BT2
PACIFIC
OCEAN
METAL-CLEANING
WASTE
IMPOUNDMENTS-
DRAINAGE
CHANNEL
POWER
PLANT
MW-12 \MW-6
\
Jl
MW-10
B11
i TREATED WASTEWATER
..... ,, \ IMPOUNDMENTSMW-ll .
-f \
\
LEGEND:
Indicates approximate location
of monitoring well.
Indicates approximate location
of background boring.
(^ Indicates number of impoundment.
| [ Indicates approximate location of
generalized geologic cross section.
CSX
KYU
12/M
AS SHOWN
MB »» 10*00706
200 400
Graohic Scale (Feet)
FIGURE 3-1
SITE PLAN
SDCJC ENONA POWER PLANT
Ion.10BO-00-005
LEGEND
A A Slope in direction of arrow
•~« Valve
(j) Control structure/sump
CONTROL
BUILDING
TREATED WASTEWATER
IMPOUNDMENTS
LOW-VOLUME WASTEWATER
IMPOUNDMENTS
TREATMENT
PLANT
METAL-CLEANING WASTEWATER
IMPOUNDMENTS
TREATMENT
PLANT
TO PUNT DISCHARGE
P) DISCHARGE PUMPS P-150 A It B
"• TO PLANT DISCHARGE
FROM
POWER
PLANT
GRAPHIC SCALE (FEET)
100
10BOOOO1
FIGURE 3-2
PLAN VIEW OF SURFACE IMPOUNDMENTS
IMPOUNDMENT CLOSURE PLAN
SOC&t ENCINA POWER
MM I I I 1 I U i I I
/VUTTELH/1USER t.corpora hon
SDG&E 3-4 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
Based on information supplied by SDG&E, the low-volume
and metal-cleaning waste impoundments overlie the location of a
former unlined waste impoundment. SDG&E has indicated that the
unlined impoundment received discharges of low-volume and
metal-cleaning wastes prior to construction of the present
impoundments. Prior to construction of Impoundments No. 1 through
4, soils in the area of the former unlined impoundment were
excavated and the area was filled.
An additional lined impoundment was constructed in an
area northeast of the present impoundments and was used as a
temporary impoundment for low-volume and metal-cleaning wastes
during construction of Impoundments No. 1 through 4.
The impoundments were installed as double-lined with a
3-inch thick upper liner and a 2-inch thick lower liner, both
constructed of hydraulic asphalt concrete (HAC). Figure 3-3
presents a schematic cross section of this impoundment liner
design.
Each impoundment has a leachate collection system which
consists of 6-inch inner diameter perforated polyvinyl chloride
(PVC) in an aggregate fill located between the liners. The
leachate collection system drains into sumps at the control
structures. The sump pumps are controlled by water-level sensors
which activate the pumps and automatically pump leachate, if
'DRAIN CLEANOUT
HYDRAULIC ASPHALT CONCRETE (3" thick)
PERFORATED
LEACHATE DRAIN.
(6" inner d!ameter)\
PORTLAND CEMENT CONCRETE
DRAIN FLUSHING RISER
(3" Inner diameter)HYDRAULIC ASPHALT
CONCRETE (2" thick)
AFTER SDG&E. 1976. POND LINING SECTION VIEW. SHEET C-10.
KKM
12/M
NONE
P1080
FIGURE 3-3
SCHEMATIC CROSS SECTION
OF TYPICAL IMPOUNDMENT
IMPOUNDMENT CLOSURE PLAN
S3CJC ENCINA POWER PLANT
A1ITTEL ion.1080-00-002
/MITTELH>4USER vcorpora hon
SDG&E 3-6 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
detected, back into the impoundments. Flushing lines between the
impoundment liners permit injection of water for the purpose of
purging the leachate collection system. The installation details
for the collection piping are presented in Figure 3-4. A summary
of impoundment design characteristics, capacity and surface area
is provided in Table 3-1.
A groundwater subdrain system was installed beneath the
lower liner of Impoundments No. 1 through 4 to relieve possible
hydrostatic uplift pressures during periods of high groundwater
elevations. The subdrain system consists of 6-inch perforated
pipe, within aggregrate-filled trenches beneath the lower liners,
that drains to a common collector and discharges to Agua Hedionda
Lagoon (Figure 3-4).
3.1.1 Impoundment Operation
The Encina Power Plant has six on-site surface
impoundments and a wastewater treatment facility for the treatment
of low-volume wastes and metal-cleaning wastes. Following
treatment, impoundment wastewaters are discharged to the Pacific
Ocean under National Pollutant Discharge Elimination System
(NPDES) Permit No. CA0001350. Sediment that accumulates in the
impoundments is analyzed and disposed in accordance with federal
and state regulations.
n
GRQUNDWAJER SUBDRAIN SYSTEM
• Perforated Subdrain (6")*
— Subdrain Collector (6")*
LEACHATE -COLLECTION SYSTEM
— Inlet Piping (6")*
- Perforated Drain (6")*
— Drain Collector (6")*
- Drain Flushing Riser (3")*
Control Structure/Sump
Drain Cleanout
Impoundment Inlet Structure
+ Inner Diameter
TREATED WASTEWATER
IMPOUNDMENTS
LOW-VOLUME WASTEWATER
IMPOUNDMENTS
METAL-CLEANING WASTEWATER
IMPOUNDMENTS
GRAPHIC SCALE (FEET)
"*" HJTCMC »r
rff ay
"*"" KKM '
1A11 12/88 '
sc'a- NOUE
f° C10B00003
w FIGURE 3-4
GROUNDWATER SUBDRAIN AND
LEACHATE COLLECTION SYSTEMS
IMPOUNDMENT CLOSURE PLAN
-— 5t>&4£ FNCINA PnWFR PI ANT
Xi4n IH U JllCCI? I awa no 1 REV
/MITTELHXUSER
SDG&E
Encina Power PlantClosure Plan
Surface Date of
Impoundment* Construction
TABLE 3-1
IMPOUNDMENT CHARACTERISTICS
ENCINA BAY POWER PLANT
Estimated
Approximate Approximate Storage
Dimensions Area, Capacity
(feet) sq.ft. (gallons)
LVW No. 1 1978 115 X 80 9,200
x 11 (depth)
LVW No. 2 1978 130 x 85 11,000
x 14 (depth)
MCW No. 3 1978 140 x 90 12,600
x 15 (depth)
MCW No. 4 1978 90 x 80 7,200
x 13 (depth)
TW No. 5 1978 120 x 85 10,200
x 6 (depth)
TW No. 6 1978 140 x 70 9,800
300,000
590,000
750,000
330,000
220,000
270,000
x 6 (depth)
60,000 2,460,000
* LVW: Low-volume waste
MCW: Metal-cleaning waste
TW: Treated wastewater
b HAC - Hydraulic asphalt concrete.
c Treated wastewater impoundments receive all metal-cleaning wastes
wastes which are treated in the chemical treatment facility.
December 1988
Rev: 0
P1080RR
1985
Estimated
Impoundment
Throughput Liner
(gal x 10') Material
10.7 HAC"
3-inch upper
2-inch lower
12 . 6 Same
1 . 8 Same
2 . 2 Same
1 . 9 Same
1 . 9 Same
and any low-volume
/HITTELH/IUSER L.^corporation
SDG&E 3-9 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
Metal-Cleaning Wastes. Metal-cleaning wastes are
generated from chemical cleaning operations within the power
plant/ including boiler fireside washes/ air preheater washes/ and
boiler water-side acid and chelant (Vertan) cleanings/
hypochlorinator cleanings and reverse osmosis cleanings. Wastes
are initially received in Impoundment Nos. 3 or 4 and then
processed through the chemical treatment facility for removal of
metals.
Low-Volume Wastes. Sources of low-volume wastes
typically discharged to surface impoundments include:
evaporator blowdown,
sample line discharges/
floor drain discharges/
demineralizer waste,
zeolite softener waste,
reverse osmosis brine, and
condenser cleaning waste.
These wastes are typically received in Impoundment Nos.
1 and 2. If an analysis indicates compliance with the plant's
NPDES permit limitations, low-volume wastes are discharged along
with the plant's cooling water system in accordance with the NPDES
permit; otherwise, they are processed through the chemical
treatment facility prior to discharge.
Treated Wastewater. Treated wastewater is discharged
from the tanks in the chemical treatment facility into Impoundment
/MITTELKMUSERcorpora hon
SDG&E 3-10 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
Nos. 5 and 6. The treated wastewater is then discharged along
with the plant's cooling water if chemical analyses indicate
compliance with the plant's NPDES permit limitations.
3.2 MAXIMUM EXTENT OF OPERATION AND MAXIMUM INVENTORY
The maximum extent of operations for the six pond system
is approximately 1.5 acres in surface area. The maximum possible
inventory, if all the ponds were simultaneously full of wastewater
or treated water, is 2,460,000 gallons. The methods of operation
would make this event highly unlikely, but it is reported per
regulatory requirements. Table 3-1 presents impoundment
characteristics for the Encina Power Plant.
These facilities are not located within the 100-year
floodplain. Rain run-off is diverted around the ponds by local
grading.
3.3 WASTE IDENTIFICATION
San Diego Gas & Electric provided detailed chemical
analyses of the waste streams in their Hydrogeologic Assessment
Report (HAR) submitted to the San Diego Regional Water Quality
Control Board. Several tables from the HAR are reproduced here
which summarize the waste composition information.
/MITTELH/4USER vcorporation
SDG&E 3-11 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
Chemicals that are used in boiler metal-cleaning
operations and that may be present in low-volume wastes are shown
in Tables 3-2 and 3-3, respectively. Results of chemical analyses
of composite samples of metal-cleaning wastes, treated wastes, and
low-volume wastes collected by SDG&E in 1985 are summarized in
Table 3-4. Chemical analyses of treated and untreated water side
acid cleaning wastes from the South Bay Power Plant are also
provided in Table 3-4 and are considered representative of similar
waste streams at the Encina Power Plant.
Samples of treated, low-volume, and metal-cleaning
wastewaters were collected from the Encina Power Plant
impoundments in January 1986. Samples were analyzed for metals,
general minerals, purgeable and extractable organics, and other
constituents according to Environmental Protection Agency (EPA)
test procedures. The results of these analyses and results of
chemical analyses of filter cake samples collected by SDG&E in
January 1986 and by Woodward-Clyde Consultants in April 1986 from
the Encina chemical treatment facility are given in Table 3-5.
Results of the analyses of a low-volume waste sludge sample
collected from Impoundment No. 1 are also presented in Table 3-5.
Chemical analyses of wastewater constituents were
compared to the applicable soluble threshold limit concentrations
(STLCs) for hazardous waste (CCR, Title 22, Article 11, Section
66699). For those constituents with established STLC values,
TABLE 3-2
CHEMICAL CONSTITUENTS OF
METAL-CLEANING OPERATIONS
ENCINA POWER PLANT
Acid Cleaning Chemicals
0 Hydrochloric Acid
0 Brornate
0 Thiourea
0 Citric Acid
0 Inhibitor - Dowell A120
Chemical Formula
HC1
HOOCCH2C(OH) (COOH)CH2
Proprietary
Chelant Cleaning Chemicals
EDTA (Vertan 675)
0 Ammonium Hydroxide
0 Ammonium Bicarbonate
0 Inhibitor - Dowell A251
(COOH-H2C)2-N-CH2-CH2-N-(CH2-COOH)
NH.OH4
NH.HCO.4 3
Proprietary
Reverse Osmosis Unit Cleaning Chemicals
0 Polycarboxylic Acid
0 Sulfamic Acid
Citric Acid
[R] COOHn
C,H.,NHSO,OHoil i
HOOCCH2(OH)(COOH)CH2
Hypochlorinator Unit Cleaning Chemical
Dilute Nitric Acid
* Table from the Hydrogeologic Assessment Report
Prepared for San Diego Gas and Electric Company
HNOr
Table 3-3
CHEMICAL CONSTITUENTS OF LOW-VOLUME WASTE
ENCINA POWER PLANT
Chemical Active Ingredient
Nalco 8331
Nalco 1367b
Nalco 71-D5b
Nalco 7328b
Nalco 356
Nalco 1362*
Nalco 789*
Nalco 1340*
Nalco 750*
Nalco 19-HC
Nalco 7763
Monosodlum Phosphate
Dibasic DIsodium Phosphate
£Trisodium Phosphate
Sulfuric Acid
Hydrochloric Acid
Nitric Acid
Sodium Bichromate
Sodium Hydroxide
Sodum Nitrite-26Z
Polyglycol-lOOZ
Polyglycol/Fatty Acids-lOOZ
Bis(tri-n-butyltin) oxlde-2.5Z
Cyclohexamine-25Z
Amlnomethylenephosphate-7Z
Polyphospate-5Z
Polyacrylate-lOOZ
Polyoxylated Clycol-lOOZ
Hydrazine-35Z
Anionic Polymer-17Z
Chemical Formula Use Where Used
NaNCK
NH2CCHCH-P04
CH2-CHOHCOOH
NaH2P04
HC1
NaOH
Corrosion Inhibitor
Deposit Penetrant
Defoamer
Microbiocide
Neutralizing Amine
Deposit Inhibitor
Deposit Inhibitor
Deposit Inhibitor
Antifoam
Oxygen Scavenger
Anionic Polymer
Boiler Water Conditioner
Boiler Water Conditioner
Boiler Water Conditioner
pH Control
Regeneration
Regeneration
Regeneration
Corrosion Inhibitor
pH Control
pH Control
Regeneration
Service Water Systems
Service Water System*
Service Water Systems
Service Water Systems
Condensate Systems
Units 1,2,3 Evaporators
Unit 5 Flash Evaporator
Unit 5 Flash Evaporator
Units 1,2,3 Evaporators
& Unit 5 Flash Evaporator
Boiler
Wastewater Treatment
Boiler
Boiler
Boiler
Wastewater Treatment
Deminerallzer
Wastewater Treatment
Hypochlorlnator
Service Water Systems
Wastewater Treatment
Service Water Systems
Demlneralizer
.Evaporators are not presently in use.
Use of these chemicals was discontinued in 1985.
°Boller blowdown Is not discharged to the impoundments.
However, Che boilers may occasionally be drained to the impoundment?.
— Chemical formula hot available.
* Table from the Hydrogeologic Assessment Report Prepared for: San Diego Gas and Electric Company
Table 3-4
IKPOUNDMENT WASTESTREAM CHARACTERISTICS - 1985
SDC&E POWER PLANTS
Wastestream Composite Samples (mg/1)
South Bay
Water-Side Water-Side Water-Side
Acid Acid Acid
•
STLCb
Constituents (mg/1)
Antimony 15.0
Arsenic 5.0
Barium 100
Beryllium 0.75
Cadmium 1.0
Total Chromium 560
Chromium VI 5
Cobalt 80
Copper 25
Lead 5
Mercury 0.2
Molybdenum 350
Nickel 20
Selenium 1.0
Silver 5
Thallium 7.0
Vanadium 24
Zinc 250
PH S2,al2.5*
Pentachlorophenol 1.7
Trichloroethylene 204
Acute Fish Toxicity 500
Reactivity g
FlnmnabiHty h
California Administrative Code,
j Sample collected at SDG&E South
24-hour composite sample.
, California Administrative Code,
100Z fish survival.
? California Administrative Code,
California Administrative Code,
Clean (Un- Clean (Un- Clean
treated)0 treated)0 (treated)
9/27/85
fc —
0.005
—
—0.08
K20
NA
--2.9
1.5
—
—43
—NA
—1.0
41
NA
NA
NA
180
None
None to
boil
Title 22,
Bay Power
Title 22,
Title 22,
Title 22,
11/3/85
-» —0.058
—
—0.01
0.50
NA
0.19
8.8
0.4
—0.11
4.0
—NA
—6.0
0.15
NA
NA
NA
1,800
None
None to
boll
Article 11,
Plant.
Article 11,
Article U,
Article 11,
11/6/85
..
0.026
—
—0.01
—NA
0.07
—
—
—0.11
—
—NA
—2.0
—13
NA
NA
49,000
None
None to
boil
Section 66699
Section 66708
Section 66705
Section 66702
Untreated
Chelant
(Vertan)
Clean
10/23/85
»
0.08
1.7
——. 2.2
—
—- 300
4.3
—
—76.0
—NA
—4
9.5
9.6
NA
NA
4,200
i
None to
boil
.
.
.
Processed
Water from
Vertan
Clean
11/4/85
••—
0.094
—
—0.01
0.25
—0.13
—0.4
—0.11
32.0
—NA
—
—0.05
12.3
NA
NA
12,000
None
None to
boil
Fireside
Wash (Un-
treated)
8/10/85
NA
—NA
NA
—
—NA
NA
1.29
—
—NA
24.8
—
—' NA
—3.96
5.2
—
—<560,000
None
NA
Encina
Fireside
Wash (Un-
treated)
10/26/86
~_
0.22
0.8
—
—2.7
NA
1.76
2.20
0.6
—
—31.
0.01
NA
—17
3
3.0
NA
NA
120,000
None
None to
boil
Water from
Fireside
Wash
(treated)
8/19/85
NA
—NA
NA
—
—NA
NA
—
—
—NA
1.2
—
—NA
—
__
5.8
NA
NA
f
None
NA
Rainbow
Tower
Slowdown
j/ 30/85
NA
—NA
NA
—12.2
1.1
NA
1.33
—
—NA
—— -
—NA
—5.01
6.95
—
—f
NA
NA
.
Low-
Volume
Waste3
8/1/85
MA
—NA
NA
—
—_-
NA
0.12
—
—NA
2.8__
__
NA__
0.25
6.6
—
—f
None
NA
Releases bromine gas when oxidized.
»-« - Not detected.
NA • Not analyzed.
* Table from the Hvdroeeoloeic Assessment- Itenorf Prona-rcsH fnT- • Ran T)T ocrr* fla ^ •3 T-» ^1 P T rt rt *- 1
Project 1 J35K-ENRP
Parameter
General Minerals
PH
Specific Conductance (umhos/cm)
Filterable Residue (IDS)
Sodium
Potassium
Calcium
Magnesium
Manganese
Iron
Chloride
Bromide
Fluoride
Sulfate
Nitrate (as NOj)
Total Phdsphorous
Alkalinity
Carbonate Alk
Bicarbonate Alk
-Hydroxide Alk
Total Alkalinity
Table 3-5
IMPOUNDMENT WASTE CHARACTERISTICS - 1986
ENCINA POWER PLANT
Solid Waste (mg/kg)Impoundment Wasteva'ter (mg/1)
TTLC*
S2.212.58
None
None
None
None
None
None
None
None
None
None
18,000
None
None
None
None
None
None
None
Filter Cak|
(January)
Dry
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Wet
10.1
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Filter Cakec
(April)
9.6
NA
NA
NA
NA
NA
NA
620
64,000
NA
~
0.1
NA
—
1700
NA
NA
NA
NA
Low- Volume
Waste Sludge
(April)
7.4
NA
NA
NA
NA
NA
NA
230
39,000
NA
0.23
NA
—
3200
NA
NA
NA
NA
STLCe
S2,a2.58
None
None
None
None
None
None
None
None
None
None
180
None
None
None
None
None
None
None
Treated ~
Wasteuater
8.8
8,500
7,000
2,300
7.1
33
3.8
0.01
0.4
3,900
—
0.49
520
~
0.3
42
31
0
73
Metal-Cleaning
Wasteuater
2.5
10,000
6,000
1.700
6.8
11
45
1.8
200
3,800
—
0.27
170
—
4.4 '
42
31
0
73
Low-Volume
Wastewater
10.8
460
280
55
0.63
16
1.4
—
—
30
—
—
14
—
0.4
42
31
0
73
Projei >. 55935K-ENRP
Table 3-5 (continued)
IMPOUNDMENT WASTE CHARACTERISTICS - 1986
ENCINA POWER PLANT
Solid Waate (mg/kg)Impoundment Wastevater (mg/1)
Parameter
Total Organic Nitrogen
Ammonia Nitrogen
Total Kjeldhal Nitrogen
Mat a Is
Arsenic
Aluminum
Antimony
Bariun
Beryllium
Cadmium
Copper
Chromium
Cyanide
Lead
Mercury
Molybdenum
Nickel
Selenium
Silver
Thallium
Vanadium
Zinc
me*
None
None
None
300
None
500
10,000
75
100
2,500
500h
None
1,000
200
3,500
2,000
100
500
700
2,400
5,000
Filter Cake
(January) Filter Cakec
Dry
NA
NA
NA
NA
NA
302
NA
8.7
7,639
83
~
365
NA
NA
14,350
NA
NA
18
NA
2.026
Wet
NA
NA
NA
32.4
NA
NA
117
NA
3
2,078
32
0.043
141
0.099
NA
5,539
0.07
NA
_-
NA
782
(April)
1,900
—1,900
22
710
—
120
0.44
0.7
2,600
46
NA
100
—
—
4,900
5.1
—
—
1.300
700
Low-Volume
Waste Sludged
(April)
5,700
—
5,700
86
2,900
—
1,700
0.31
3.5
780
270
NA
670
14
--
6,100
1.7
1.6
—
11,000
790
STLCe
None
None
None
5
None
15
100
0.75
1.0
25
5h
None
5
0.2
350
20
1
5
7
24
250
Treated Metal-Cleaning Low-Volume
Wastevater Wastevater Wastevater
55 22 1
11 11 0.4
66 33 1.4
0.022 0.14 —
0.43 2.6 —
—
0.044 0.26 0.097_
—
—
0.6 0.18
NA NA NA
—
0.001 0.0021
0.15
0.13 3.2
—
—
—
0.7 5.5 0.16
0.07 0.89 —
Proj o. 55935K-ENRP
Table 3-5 (concluded)
IMPOUNDMENT WASTE CHARACTERISTICS - 1986
ENCINA POWER PLANT
Solid Waste (mg/kg)Impoundment Wastevater (mg/1)
Parameter
Organic Compounds
Oil and Crease
Phenolics
EDTA
Hydrazine
Thlourea
1,1, l-Trichloroe. thane
Tetrachloroethylene
Toluene
Catbon Disulflde
2-4. Dlmethylphenol
C10-C36 Hydrocarbon Matrix
C16-C36 Hydrocarbon Matrix
Acetophenone
C-10 Nitrogen Compound
Anfolecular Sulfur
TTLC*
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
Filter Cakg Low-Volume .
(January) Filter Cakec Waste Sludge
Pry
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Wet (April) (April)
3.5 1000 170,000
NA — 54
NA 5.4 5.0
NA
NA
NA
NA — 0.7
NA
NA
NA
NA 10,000
NA -- 400,000
NA
NA 40
NA
STLC6
None
None
None
None
None
None
- None
None
None
None
None
None
None
None
None
Treated Metal-Cleaning Low-Volume
Wastewater Wastevater Wastevater
19 42 —
0.17 0.16 0.13
NA NA NA
NA NA MA
NA NA NA
0.002
0.001
0.010
0.800 -- 0.02
0.012 -- —
—
~
0.1 — 0.02
•
0.3
— Not detested, NA - Not analyzed
* Total Threshold Limit Concentration, California Administrative Code, Title 22, Article 11, Section 66699.
Sample collected and analyzed by SDG&E in January 1986.
*' Sample collected from chemical treatment facility by WCC in April 1986.
Sample collected by WCC from Low-Volume Waste Impoundment No. 1 in April 1986.
" Soluble Threshold Limit Concentration, California Administrative Code, Title 22, Article 11, Section 66699.
Samples collected b'y SDG&E and WCC from impoundments in January 1986.
* California Administrative Code, Title 22, Article 11, Section 66708.
TTLC and STLC provided are for Chromium VI.
* Table from the Hydrogeologic Assessment Report Prepared for: San Diego Gas and Electric Company
/MITTELhMUSER tcorporation
SDG&E 3-16 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RC
wastewater concentrations in January 1986 samples from the
impoundments were below the applicable STLCs. However, 1985
composite waste stream samples of boiler water-side acid
cleanings, at the South Bay Power Plant exceeded STLCs for
nickel, toxicity and pH. Chelant cleanings and boiler fireside
wash wastes at the Encina Power Plant exceeded STLC's for nickel
and copper. Concentrations of copper and nickel in the 1986
filter cake sample exceeded the applicable total threshold limit
concentrations [ (TTLCs) CCR, Title 22, Article 11, Section
666999] . Concentrations of nickel and vanadium in the 1986
low-volume waste sludge exceeded the applicable TTLCs.
None of the constituents analyzed in wastewater samples
exceeded criteria for restricted hazardous wastes (Section
25122.7, California Health and Safety Code). Furthermore, none of
the concentrations of constituents analyzed in waste stream,
wastewater, sludge, or filter cake samples exceeded TTLCs for
extremely hazardous wastes (CCR, Title 22, Article 11, Section
36723) .
/MITTELH/IUSER v'corporation
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
SECTION 4.0
CLOSURE PROCEDURES
/HITTELU4USER t."corporation
SDG&E 4-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
4.0 CLOSURE PROCEDURES
4.1 CLOSURE PERFORMANCE STANDARDS
During closure of the wastewater ponds at the Encina
Power Plant, SDG&E intends to remove all wastes and contaminated
materials to agreed upon levels from the wastewater ponds. Upon
completion of closure activities, there will be no threat to human
health or the environment. Extended post closure maintenance is
therefore not anticipated. Until closure is complete, SDG&E will
continue to take all steps to prevent threats to human health and
the environment and will maintain current security operations.
All closure activities will be conducted under
supervision of an independent engineer or a registered engineering
geologist. A detailed written narrative of closure activities
will be prepared, certified and submitted to the regulatory
agencies after closure has been completed.
4.2 SITE CLEANUP STRATEGY
4.2.1 Introduction
The State of California requires removal or
decontamination of waste residues, contaminated liners and
contaminated subsoils when a surface impoundment is closed. This
/MITTELH/4USER L.corporation
SDG&E 4-2 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
requirement, in 22 CCR67288 and 23 CCR2582, does allow
contaminated subsoil to remain at a closed surface impoundment if
it can be shown that it does not pose "a significant hazard to
water quality, public health, domestic livestock, wildlife or the
environment." A site cleanup strategy for closure of the surface
impoundments is described in this section. The strategy will be
utilized to decide if subsoils are contaminated, and, if they are
contaminated, whether the subsoils may be left on-site.
4.2.2 Analysis Parameters
To develop a cleanup strategy, it is necessary to
identify analysis parameters and the action levels that will
indicate whether the subsoils are contaminated. The parameters to
be analyzed are based on past analyses of four types of samples
associated with the impoundments:
1. Waste streams that were discharged to the impoundments;
2. Wastewater in the impoundments;
3. Solids filtered or settled from the impoundments'
contents; and
4. Soil samples from borings beneath and adjacent to the
impoundments.
The samples of the four media were taken as part of two
earlier studies of the impoundments, "Hydrogeologic Assessment
Report, Encina Power Plant," September 1986 and "Remedial
Investigation, Encina Power Plant," February 1988. Analytical
/V1ITTELH>1USERcorporation
SDG&E 4-3 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
data tables from these reports are presented in Chapter 3.0 and in
Attachment 4-1. Locations of the samples and discussions of the
analytical results can be found in those studies. The following
discussion will focus only on constituents that were present in
the wastes placed in the impoundments and on waste constituents
that were present in subsoil samples at concentrations greater
than the background concentrations.
Table 2.3-3 from the Hydrogeologic Assessment Report
(HAR) is presented in Chapter 3.0, Table 3-4. It lists
concentrations of metals and a few other parameters in waste
stream composite samples. These analyses indicate that
concentrations of copper and nickel in several waste streams
exceeded the STLCs. Concentrations of metals and other parameters
listed in Table 2.3-4 from the HAR and presented in Chapter 3.0,
Table 3-5, indicate that filtered and settled solids from the
impoundments were hazardous because total copper, nickel and
vanadium exceeded the respective TTLCs. In addition, arsenic,
barium, chromium, lead and mercury concentrations in these samples
exceeded ten times the STLCs. Concentrations of metals in
wastewater in the impoundments were less than the STLCs.
Concentrations of other parameters, including specific organic
compounds, were low in both the solids and wastewater. Oil and
grease, phenolics, and hydrocarbons were high in the solids.
TPH will be used as an indicator parameter for organics during
closure.
/V1ITTELH/4USER tcorporation
SDG&E 4-4 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
Tables 7.2-1 and 7.2-2 from the HAR are presented in
Attachment 4-1. They present analytical data for samples taken
from borings around the perimeters of the impoundments. Samples
Ell-2 (Table 7.2-1), E10-3, E10-7, Ell-2 and E12-2 (Table 7.2-2)
are far enough away from the impoundments that they were
considered background samples. A comparison of samples taken near
the impoundments to the background samples was made. Those
parameters whose concentrations exceeded twice the average
background concentration, by soil type, include barium, chromium,
copper, nickel and zinc. Samples near the impoundments were also
compared in the HAR to the background samples using a statistical
frequency distribution. This evaluation showed that beryllium,
copper, nickel and zinc had bi-normal distributions, indicating
two or more dissimilar sample populations.
Based on the analytical data discussed above, the
Regional Water Quality Control Board suggested that soil samples
from beneath the impoundments be analyzed to determine the extent
to which soil remediation might be necessary. SDG&E subsequently
retained a consultant to perform a RI. Table 5.2-1 from that
report is presented in Attachment 4-1. Analytical data for nine
metals and total petroleum hydrocarbons are listed in that table.
The samples came from borings through the bottoms of the
impoundments and were intended to show if contamination had
occurred directly beneath the impoundments. The parameters
selected for these analyses are the same as those which were
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mentioned above as being in the wastes or in soils at
concentrations greater than background concentrations.
In the RI the data presented in Table 5.2-1 were
compared to background data using Cochran's approximation to the
Behrens-Fisher Student's t-test. Arsenic, chromium/ nickel/ lead
and vanadium concentrations were statistically different by this
evaluation. The results of the statistical analysis is presented
on Tables 6.1 and 6.2 in Attachment 4-1.
Based on the extensive past analyses described above/ 11
parameters will be analyzed during closure: total petroleum
hydrocarbons/ pH, arsenic, barium, chromium, copper, mercury/
nickel, lead, vanadium and zinc. Total petroleum hydrocarbons was
selected as a screening parameter to indicate migration of
petroleum wastes from the impoundments; pH will indicate the
extent to which acidic or basic wastewaters have altered soil
chemistry. The nine metals are those that have been present in
relatively high concentrations in wastes or subsoils according to
the criteria discussed above.
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4.2.3 Cleanup Levels
Cleanup levels will be based on naturally occurring
total background concentrations of the 11 parameters. The basis
for determining cleanup levels in soils is presented in Attachment
4-2. For each parameter a separate cleanup level will be
calculated for each soil type and for each of the two impoundment
areas.
There are analytical data for four background samples in
the HAR and for ten samples in the RI. SDG&E will use this data
and augment it with data from four borings/ two each in
uncontaminated areas near the two impoundment areas. Samples will
be taken every two feet to groundwater in each boring. A minimum
of two and a maximum of four samples will be analyzed from each
soil or formation type in each boring. The other samples will be
archived for possible later analysis.
Soil cleanup levels for total metal concentrations equal
to the mean plus three standard deviations will be calculated
separately for each soil type in each of the two impoundment
areas. The basis for mean plus three standard deviations is
presented in Attachment 4-2.
Samples beneath the surface impoundments will be
analyzed for the same 11 parameters as the background samples.
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The total metal concentrations in potentially contaminated soils
will then be compared to the cleanup levels to determine whether
significant contamination has occurred. If the concentration of
any metal exceeds the respective cleanup level, the soil may be
sampled and analyzed again. The reanalysis must confirm
contamination or the soil will be considered clean.
Alternate approaches may be proposed to the regulators
by SDG&E for addressing low levels of contaminants. One such
approach is presented in Attachment 4-3. This Attachment
describes procedures used under similar site circumstances where
there were no beneficial uses of the shallow groundwater with
elevated metals. Samples were analyzed using a deionized water
extraction. The extraction evaluates the potential for metal
ions to migrate through soils. The rational for using this test
which has been approved by regulators is presented in
Attachment 4-3. The basis for this decision is available
health-based information. Alternatively, contaminated soil may be
treated in place.
Once the spatial extent of soil contamination is
determined, the soils will be excavated for proper disposal or
treatment. After removal or treatment of contaminated soil,
confirmation samples will be taken in which pH and total
concentrations of the nine metals will be analyzed. If earlier
samples exceeded the background standards for total petroleum
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hydrocarbons, hydrocarbons will also be measured in the
confirmation samples. Analytical results from the confirmation
samples are expected to indicate that contamination has been
removed or successfully treated. However, if the tests show
contamination still exists, up to two feet more of soil will be
removed and the soils retested. Sampling, analysis and removal
will continue until the soil is found to be uncontaminated or
groundwater is reached. If excessive contamination exists, SDG&E
may decide to leave the contaminated soils in place and proceed
with post-closure. In the latter event, the regulatory agencies
will be contacted and a remedial action plan developed.
The site cleanup strategy is summarized in Attachment
4-4, Closure Decision Diagram. The diagram shows what tests will
be run and how the results will be used to determine waste
classifications for soil underlying the surface impoundments.
4.3 APPROACH TO CLOSURE
This section is a description of SDG&E's overall
approach for closure of the surface impoundments. Extensive
analytical data associated with soils and groundwater underlying
the impoundments and the asphalt liners of the impoundments have
already been collected. The analytical data, which is described
in Section 4.3.1, will be supplemented during closure by
additional sampling in contaminated areas.
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Closure activities are summarized in Section 4.3.2; the
actual closure steps are described in Section 4.4. During
implementation of the closure steps, samples of water/ asphalt
concrete, gravel and soils will be collected. Attachment 4-5,
"Sampling and Analysis Plan," describes the procedures for
collecting and analyzing the samples.
4.3.1 Existing Analytical Data
As mentioned above, extensive soils characterization
data have been previously collected by SDG&E as part of two
earlier studies, "Hydrogeologic Assessment Report, Encina Power
Plant," September 1986 (HAR) and "Remedial Investigation, Encina
Power Plant," February 1988 (RI). Data tables from these reports
are reproduced in Chapter 3.0 and Attachment 4-1.
During the implementation of the RI, samples of the
asphalt liners (upper and lower) and soils underlying the surface
impoundments were obtained and analyzed. The groundwater
monitoring data collected through 1987 was reviewed for
significant increases.
Samples of the asphalt liners (upper and lower) were
obtained and analyzed for moisture content, pH, TTLC and STLC.
These results indicated that the liners are not hazardous
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materials. These results are presented in Attachment 4-1, Table
5.1.
The soil samples underlying the surface impoundments
were collected and analyzed for moisture content, total petroleum
hydrocarbons (TPH), pH, TTLC and STLC. These results indicated
that none of the soils underlying the surface impoundments are
hazardous materials except for LVW 2. The STLC limit for
vanadium, 24 mg/1, was exceeded in boring B-2 at a depth of
1.5-2.5 feet. These results are presented in Attachment 4-1,
Tables 5.2-1, 5.2-2 and 5.3.
The soil and groundwater analytical data were then
evaluated statistically to determine if significant contamination
had occurred. The results of these evaluations are shown in
Tables 6.1 and 6.2 in the RI. These tables are reproduced in
Attachment 4-1.
Soil beneath the Low Volume Waste Pond 1 (LVW 1) was
found to be contaminated with chromium and nickel and copper. The
soil beneath the Low Volume Waste Pond 2 (LVW 2) was found to be
contaminated with nickel and vanadium. Soil beneath LVW 1 and
Metal Cleaning Waste Pond 4 (MCW 4) had an extreme value for
vanadium concentration.
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Soil beneath Treated Waste Ponds 5 and 6 (TW 5 and 6)
was found to have a statistically significant level of arsenic.
This increase may be from comparing the soil results to background
levels which may not represent the material underlying the
impoundments. Finally, groundwater in well 5/ adjacent to TW 5,
showed statistically significant levels of nickel.
After reviewing the RI, the California Regional Water
Quality Control Board (RWQCB), San Diego Region, concluded in a
letter dated May 11, 1988, that "a polluted vadose zone exists
beneath LVW impoundment No. 2". The RWQCB has required soil
remediation beneath LVW 1 and 2. The May 11 letter is presented
in Attachment 4-6.
Based on the soil results and the statistical analyses
described above and the conclusions of the RWQCB expressed in the
May 11 letter, SDG&E proposes to sample soil beneath LVW 1 and 2
during closure to determine the extent of contamination.
The samples of soil beneath the other four ponds did
not indicate any contamination in levels which would require
remediation. However, since these ponds will not be closed for
approximately two years, random soil sampling and analysis will
be performed during closure to verify that no soil contamination
exists.
/MITTELH>1USER t.corporation
SDG&E 4-12 December 1988
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4.3.2 Summary of Closure Activities
At the start of closure/ discharges to the surface
impoundments will cease, and any remaining wastes in the ponds
will be treated in the wastewater treatment system and discharged
to the Pacific Ocean in compliance with the plant's NPDES permit.
Piping to the surface impoundments that will not be
used with the above grade tank system will be flushed with water.
The final wash water will be tested to confirm that the lines are
decontaminated. The lines will then be either abandoned in place
or removed and either disposed off-site. The impoundments
themselves will be washed or cleansed using high pressure water
and/or steam, as appropriate. The resulting wastes will be pumped
to the wastewater treatment system for treatment and then
discharged in accordance with the NPDES permit. Alternatively,
the wastes may be placed in portable tanks and then disposed of
off-site at an approved disposal site.
After cleaning is completed, the surface impoundments
will be inspected for structural damage and visible contamination
on the asphalt liner. The inspection will be performed as
described in Attachment 4-5, Sampling and Analysis Plan.
The two liners and the gravel between the liners will be
sampled and analyzed to demonstrate that they have been
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decontaminated. If structural damage or areas of visual
contamination are reported during the inspection, the asphalt
concrete liners and gravel between the liners will be sampled at
that point. If no deterioration is observed during the
inspection, the sample points will be randomly selected for the
units which have no previous indication of contamination. At LVW
1 and 2, sample points will be selected authoritatively in order
to help determine the extent of existing contamination. Samples
from each boring will be taken and analyzed for metals in
accordance with the Sampling and Analysis Plan, Attachment 4-5.
Previous analysis has shown the liners to be non
hazardous. However, if the liner or gravel is hazardous, it will
be transported off-site to a hazardous waste disposal facility.
If the liners and gravel are not hazardous, they will
either be broken up and buried on site or excavated and
transported to an off-site facility, such as a municipal
landfill. The choice of the method for disposal will depend on
the classification by the RWQCB of the backfilled surface
impoundments. If the RWQCB plans to classify the surface
impoundments as landfills if the asphalt and gravel are buried,
the liners and gravel will be disposed of off-site. If the RWQCB
does not classify the impoundments as landfills, SDG&E will
dispose of the these materials with the backfill material placed
in the impoundments.
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Soil samples will be taken below or around each
impoundment to determine if any contamination exists below the
ponds or, if necessary, the vertical and horizontal extent of any
soil contamination underlying the ponds. The sampling locations
will be randomly selected in the units where previous analysis
does not indicate significant contamination and liner
deterioration is not evident. Sampling locations will be
authoritatively placed in units where, based on the history of the
site, analytical results presented in the RI, and results of the
inspection of the liner, contamination is suspected or confirmed.
Soil will be segregated by classification: background,
contaminated (statistically greater than background levels) and
hazardous. Contaminated soils will be disposed based on their
classification as either hazardous or non-hazardous waste. Soils
with concentrations less than the background levels will be left
on-site. After removal of contaminated soils, additional
confirmation samples will be taken and analyzed for the identified
constituents.
SDG&E will work closely with the regulatory agencies
during implementation of the soil sampling and analysis
activities. Should excessive soil contamination preclude clean
closure, a revised closure plan and a post-closure plan will be
submitted. The revised closure plan will outline the activities
/MITTELH/1USER vcorporation
SDG&E 4-15 December 1988
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Closure Plan P1080RD
to close the area as a landfill and will describe the activities
that will be completed during the post closure period.
4.4 FINAL CLOSURE ACTIVITIES
/
Final closure of the impoundments will commence
approximately two months after the new aboveground tank system has
been operating. The expected starting date for closure activities
is August 1990. However, this date may be impacted due to local
grading requirements which are out of SDG&E's control. These
requirements do not allow grading operation to occur between
October and April
Normal operation includes treatment of wastewater and
discharging to the Pacific Ocean in compliance with the NPDES
permit and removal of sludges by a registered hauler to an
approved off-site facility. It is expected that the impoundments
will be empty/ or nearly empty/ at the start of closure
operations.
Throughout closure, SDG&E will consult with the
regulatory agencies to inform them of any unexpected events which
might impact the closure activities and will notify them at least
48 hours prior to inspection of the impoundments, sampling
activities and removal of the liners.
/MITTELH/IUSER t.corporation
SDG&E 4-16 December 1988
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The following closure steps will be implemented after
approval of the Closure Plan by RWQCB and DHS:
Step 1: Notify RWQCB and DHS 14 days before implementation of
the approved Closure Plan.
Prepare Site Specific Health and Safety Plan for the
implementation of the closure plan.
Step 2: Treat any wastewater and sludges remaining in the pond
using the wastewater treatment system. Discharge the
treated wastewater to the Pacific Ocean in compliance
with the NPDES Permit. The sludges will be dewatered
and disposed of as a hazardous waste.
Step 3: Disconnect the piping associated with the surface
impoundments.
Step 4: Wash the surfaces of the impoundment liners to remove
any remaining waste residues. The asphalt concrete will
be washed using either a hydroblaster or steam cleaner.
The wash water will be collected using a pump or vacuum
truck and placed in a portable tank or will be
transferred to the wastewater treatment system.
Step 5: Flush with water the piping that is associated with the
surface impoundments and will not be used with the new
tank system. The flush water will be collected in the
surface impoundments. A sample of the flush water will
be obtained and analyzed for the parameters listed in
the Sampling and Analysis Plan, Attachment 4-5. If the
flush water is hazardous, the piping will be flushed and
the water sampled again. This will continue until the
piping flush water is not hazardous. After flushing of
the piping is complete, the flush water will be treated
in the wastewater treatment system. Flushed piping will
be abandoned inplace.
Step 6: Inspect the asphalt concrete liner for structural damage
and any signs of leakage. Document the inspection as
described in Part C of Attachment 4-5, "Sampling and
Analysis Plan."
Step 7: Sample and analyze the asphalt concrete (top and lower)
liners and the gravel between the liners in accordance
with the Sampling and Analysis Plan in Attachment 4-5.
The analytical results will be compared to the
background values identified in the RI.
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The material will be left on-site or disposed at an
appropriate landfill, depending on analytical results
and the RWQCB determination of the classification of the
material. The material will be left on-site if RWQCB
agrees that this would not constitute a landfill
regulated under Title 23. If on-site disposal will
result in the area being regulated as a landfill/ the
material will be excavated and disposed at an
appropriate off site landfill.
Step 8: Test the underlying and surrounding soil for
contamination. Evaluate and decontaminate the site as
described in Section 4.3, Site Cleanup Strategy. See
Attachment 4-5, "Sampling and Analysis Plan," for
detailed procedures.
Step 9: Remove any contaminated soil and dispose as appropriate
based on its waste category.
Step 10: Confirm that the site is decontaminated by testing for
total petroleum hydrocarbons, pH and metals in
accordance with the Sampling and Analysis Plan. If
contamination exists, continue soil removal and testing
until site is decontaminated.
If soil analyses demonstrate low levels of
contamination, SDG&E may propose using a deionized water
extraction test for evaluating the potential threat to
human health or the environment from the metal ions in
the soils. A rationale for this methodology is
presented in Attachment 4-3.
If excessive contamination is found, meet with
regulatory agencies and develop a revised closure plan
and a post-closure plan.
Step 11: Backfill the excavation with the existing berms and
supplement as necessary with clean fill material.
Step 12: Certify closure of the surface impoundments in
accordance with the approved Closure Plan. Submit to
DHS and RWQCB certification by SDG&E and an independent
professional engineer or a registered engineering
geologist (registered in California) that the surface
impoundments have been closed in accordance with the
approved Closure Plan.
An independent engineer and/or a registered engineering
geologist will direct the appropriate steps of closure.
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4.5 SCHEDULE FOR CLOSURE
After approval of the Closure Plan, all hazardous wastes
will be emptied from the surface impoundment within 90 days
following the start of closure, as required. All closure
activities will comply with the approved Closure Plan and will be
completed within the required 180 day time period. The
time period to complete closure may be extended due to local
grading activity restrictions during the months between October
and April which are out of SDG&E's control.
The following table shows the estimated time required to
complete each step of the closure process.
Days Required to
Closure Activity Complete Activity
1. Notify regulatory agencies
2. Remove wastes from impoundments 10
3. Disconnect pipelines 10
4. Flush and sample pipelines 5
5. Decontaminate impoundments 5
6. Inspect concrete 5
7. Sample and dispose of liner material 30
8. Sample and test underlying soil 30
9. Remove contaminated soil 40
10. Retest soil and remove as necessary 25
11. Backfill excavation 15
12. Certify closure 5
TOTAL 180 days
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4.6 POST-CLOSURE PLAN
It is assumed that no hazardous wastes or constituents
above background levels will remain in soil surrounding the
impoundments after closure. If, during closure, the results of
the sampling and analysis program indicate subsoils to be
hazardous and SDG&E makes the decision to not remove the hazardous
waste, a Post-Closure Plan will be prepared and submitted to EPA,
DHS and RWQCB for approval, in accordance with State and Federal
Regulations.
/MITTELKMUSER ucorpora Hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RD
ATTACHMENT 4-1
ANALYTICAL DATA FROM RI
Project No. 8753249K-ENRP
TABLE 5.1
HAG CORE SAMPLE ANALYSES
ENCINA POWER PLANT
(Units • rag/kg, unless noted otherwise)
Impoundment
Background
LW1
MCW4
TW6
Liner
Patch
Mix
Patch
Mix*
Patch
Mix*
Upper
Lower
Upper
Lower
Upper
Lower
Sample I.D.
Number
ENC-NPA-HAC-10/28
SB-NPA-HAC-10/27
SB-NPA-HAC-11/3
ENC-P1-B1-UL
ENC-P1-B1-LL
ENC-P4-B6-UL
ENC-P4-B6-LL
ENC-P6-B10-UL
ENC-P6-B10-LL
Detection Limits
TTLC
Moisture
Content
(Z)
ND
ND
ND
2.16
5.39
ND
ND
ND
ND
1.0
NA
PH
(units)
6.77
7.29
6.98
7.26
7.12
10.65
9.79
9.74
9.16
—
NA
As
2.3
4.8
3.3
5.1
7.7
ND
8.9
ND
9.0
1.0
500
Ba
18.2
25.7
12.4
51.2
30.1
9.6
30.3
7.6
29.1
NA
10000
Cr
2.9
1.1
7.6
17.6
2.6
2.1
ND
ND
ND
0.5
500
Cu
10.6
5.2
27.4
32.4
10.6
10.8
19.1
17.6
12.2
NA
2500
Hg
ND
ND
ND
2.6
ND
ND
ND
ND
ND
0.25
20
Ni
16.3
7.8
10.5
204.0
15.3
10.4
13.7
11.0
10.7
NA
2000
Pb
1.0
ND
ND
39.3
1.5
3.1
1.7
2.3
2.4
1.0
1000
V Zn
10.5 5.7
17.5 8.3
10.2 7.6
221.0 14.9
22.4 10.0
16.2 9.1
22.0 25.9
5.5 8.9
14.4 9.8
NA NA
2400 5000
HAC CORE WASTE EXTRACTION TESTS
(Units - ng/I)
LVW1
MCW4
TW6
Upper
Lower
Upper
Lower
Upper
Lower
ENC-P1-B1-UL
ENC-P1-B1-LL
ENC-P4-B6-UL
ENC-P4-B6-LL
ENC-P6-B10-UL
ENC-P6-BIO-LL
Detection Limits
STLC
—
—
~
—
NA
—
—
—
--
NA
0.02
0.08
0.04
0.04
ND
ND
0.02
5.0
3.6
0.8
0.4
1.3
0.7
1.1
NA
100.0
0.1
ND
ND
ND
ND
ND
0.1
5.0
ND
ND
ND
0.8
ND
ND
0.2
25.0
ND
ND
ND
ND
ND
ND
0.005
0.20
0.9
ND
ND
0.1
ND
ND
0.1
20.0
1.8
ND
0.02
0.31
ND
ND
0.02
5.0
2.6 0.2
ND ND
ND ND
0.4 0.4
ND ND
ND ND
0.1 0.1
24.0 2SO.O
Abbreviations:As - Arsenic, Ba • Barium, Cr " Chromium, Cu - Copper, Hg » Mercury, Nl - Nickel, Pb - Lead, V - Vanadium, Zn • Zinc,
ND - Not detected above laboratory detection limit
— • Not Analyzed
NA - Not Applicable/Not Available
LVW1 • Low-Volume Waste Impoundment No. 1
MCW4 - Metal-Cleaning Waste Impoundment No. 4
TW6 - Treated Waste Impoundment No. 6
*Parch Mix samples from South B.iv site
Project No. 8753249K-ENRP
TABLE 5.2-1
1987 SOIL CHEMICAL ANALYSES
ENCINA POWER PLANT
(Units - mg/kg, unless noted otherwise)
LVW AND MCW IMPOUNDMENT BORINGS
Impoundment
West
Background
LVW1
LVW2
MCW3
MCW4
Approximate
Depth
Interval
Sampled*
Boring (feet)
B-12 0.5-1.0
2.0-2.5
5.0-5.5
10.0-10.5
17.0-17.5
B-l 0-0.5
1.0-1.5
3.5-4.0
5.0-5.5
11.5-12.0
B-2 ' 0-1.0
1.5-2.5
2.5-3.5
12.0-13.0
B-3 0-1.0
1.5-2.0
3.5-4.0
7.5-8.0
9.5-10.0
B-4 0-0.5
1.0-1.5
3.5-4.5
8.0-9.0
B-5 0.5-1.5
2.0-3.0
3.0-4.0
8.0-9.0
B-6 0.5-1 J
2.0-^.5
3.5-4.0
7.0-7.5
ASTM*
Soil
Type
(SM/SC)
(SM/SC)
(SM)
(SO
(SP)
(SM)
(SM)
(SM/SP)
(SC)
(SM)
(SP)
(SP)
(SM/SC)
(SP)
(SP/SC)
(SM/SC)
(SM/SC)
(SM)
(SP)
(SW)
(SW)
(GP)
(SP)
(SW)
(SW)
(SW)
(SP)
(SO
(SM/ML)
(SC)
(SW)
Sample Moisture
I.D. Content
Number (Z)
ENC-WBB-B12-1 10.7
ENC-WBB-B12-2 10.7
ENC-WBB-B12-4 9.53
ENC-WBB-B12-5 10.6
ENC-WBB-B12-7 21.5
EN-P1-B1-1 9.53
EN-P1-B1-2 8.29
EN-P1-B1-4 7.99
EN-P1-B1-5 10.60
EN-P1-B1-9 16.90
ENC-P2-B2-1 ND
ENC-P2-B2-2 11.6
ENC-P2-B2-3 12.3
ENC-P2-B2-9 19.9
ENC-P2-B3-1 10.6
ENC-P2-B3-2 14.5
ENC-P2-B3-4 15.1
ENC-P2-B3-7 25.7
ENC-P2-B3-9 21.4
ENC-P3-B4-1 6.53
ENC-P3-B4-2 9.41
ENC-P3-B4-5 1.46
ENC-P3-B4-8 21.0
ENC-P3-B5-1 5.82
ENC-P3-B5-2 5.86
ENC-P3-B5-3 9.96
ENC-P3-B5-6 18.6
ENC-P4-B6-1 12.9
ENC-P4-B6-2 6.69
ENC-P4-B6-3 11.9
ENC-P4-B6-4 8.16
Detection Limits: 1.0
TTLC NA
Total
Petroleum
Hydrocarbons
(Method pH
418.1) (Units)
3
5
24
8
ND
170b
17
11
52
62
420b
40
96
3
24
3
ND
22
12
37
81
23
12
220b
87
13
10
7
ND
31
11
1.0
NA
8.28
6.07
9.20
9.60
9.02
7.59
6.98
7.10
8.05
7.95
6.48
8.33
8.95
5.91b
8.73
8.48
8.72
8.59
8.28
5.95b
8.38
7.89
8.32
8.73
8.70
8.12
8.42
7.93
7.41
6.15
4.82b>
NA
NA
As
4.5
3.3
8.8
2.5
1.7
5.1
7.0
4.2
7.7
7.5
1.7
3.8
4.9
ND
5.8
6.0
5.3
1.4
ND
3.7
3.6
2.0
ND
1.8
1.9
2.5
ND
3.0
3.7
2.7
1.0
1.0
500
Ba
59.9
40.4
56.3
32.1
22.8
31.9
35.7
27.0
43.1
50.0
44.6
65.0
66.2
12.2
87.0
128. Ob
86.6
26.0
8.0
23.9
47.8
5.7
5.9
30.9
19.8
17.0
6.4
21.1
21.3
25.2
8.6
NA
10000
Cr
5.5
5.2
5.5
5.2
3.3
7.7
10.9
7.9
7.5
9.9
6.3
5.2
1.6
2.6
4.5
1.9
5.7
6.2
1.9
4.8
5.2
5.2
4.3
3.6
3.4
2.0
4.5
6.0
4.4
5.0
5.5
NA
500
Cu
8.0
4.2
5.7
2.2
1.1
9.0
11.0
8.1
11.0
10.7
5-V12. lb
6.7
1.2
3.4
1.4
1.5
1.7
ND
5.6
3'6b22.5b
2.6
3'6b30. Ob
2.1
1.7
3.5
2.0
11. lb
2.5
1.0
2500
«R
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.25
20
Nl
3.1
1.5
2.3
1.7
ND
6.4
4.8
11.3
42.7b
4.2
!'*b214.0b
3.5
ND
4.6
1.6
ND
ND
ND
4.4
2.2
5.6
3.0
1.5
4.2
2.2
3.1
7.4b
3.5
3.4
2.0
1.0
2000
Pb
5.0
5.9
15.2
3.9
2.2
2.9
4.7
2.0
4.0
4.5
2.0
8.3
5.4
ND
4.6
4.9
4.1
6.4
ND
3.5
3.2
3.1
1.1
2.3
2.1
1.7
1.4
4.0
4.4
2.9
1.7
1.0
1000
V
15.8
19.5
17.1
13.1
10.0
25.8
23.1
30.6
118.0b
18.5
37.5.
530.0b
16.2
9.2
20.1
7.7
11.1
10.2
6.3
24.1
20.0
11.8
10.7
15.2
17.6
11.3
14.3
25.0b
16.6
16.9
16.4
NA
2400
Zn
36.3
17.3
26.8
12.7
9.6
13.7
16.7
13. !•<
12.8-
21. 3X
13.4
15. 8£
19.0
4.2
15.4
12.4
17.6
7.0
2.7
14.1
13.8
16.0
6.3
12.2
7.8
6.4
9.3
10.0
6.1
27.5
3.6
NA
5000
Project . 8753249K-ENRP
TABLE 5.2-1 (concluded)
1987 SOIL CHEMICAL AHALYSES
ENCINA POWER PLANT
(Units - mg/kg, unless noted otherwise)
TW IMPOUNDMENT BORINGS
Approximate
Depth
Interval
Sampled*
Impoundment Boring (feet)
East B-ll 9.5-10.0
Background 10.5-11.0
12.0-12.5
23.5-24.0
32.0-32.5
TW5 B-7 0.5-1.0
2.0-2.5
5.0-5.5
13.5-14.0
24.0-25.5
B-8 0,5-1.0
2.0-2.5
5.0-5.5
| O C 1 /, ft1 J* 3— iH .U
26.0-26.5
TW6 B-9 0.5-1.0
2.5-3.0
3.5-4.0
7.5-8.0
12.5-13.0
22.0-22.5
B-10 0.5-1.0
2.0-2.5
3.5-4.0
12.5-13.0
19.0-19.5
ASTMa
Soil
Type
(GW)
(GW)
(SW)
(SM/SW)
(SM/SC)
(SC)
(SC)
(SW)
(SW)
(SW/SC)
(SC/SW)
(SC/SW)
(SP)
fCD\(SP)
(SM)
(SW)
(SW)
(SW)
(ML/CL)
(SW)
(GP)
(SW)
(SW)
(SW)
(SC/SW)
(SC/SW)
Sample
I.D.
Number
ENC-EBB-B11-2
ENC-EBB-B11-3
ENC-EBB-B11-4
ENC-EBB-B11-6
ENC-EBB-B11-9
ENC-P5-B7-1
ENC-P5-B7-2
ENC-P5-B7-4
ENC-P5-B7-6
ENC-P5-B7-11
ENC-P5-B8-1
ENC-P5-B8-2
ENC-P5-B8-4vur* DC 11 Q AtnL— rj— Bo— D
ENC-P5-B8-12
ENC-P6-B9-1
ENC-P6-B9-2
ENC-P6-B9-3
ENC-P6-B9-4
ENC-P6-B9-5
ENC-P6-B9-9
ENC-P6-B10-1
ENC-P6-B10-2
ENC-P6-B10-3
ENC-P6-B10-5
ENC-P6-B10-7
Detection Limits:
TTLC:
Moisture
Content
(Z)
4.53
2.77
4.40
6.99
20.5
5.77
5.40
2.66
6.12
14.6
7.50
5.46
7.24
A C 1
19.0
5.75
2.61
1.81
14.7
4.03
12.4
2.40
9.60
2.93
4.10
8.94
1.0
NA
Total
Petroleum
Hydrocarbons
(Method pH
418.1) (Units) As
ND
16
4
ND
2
5
ND
ND
10
38
19
5
ND
wnN1J
ND
ND
ND
ND
ND
ND
25
ND
4
ND
ND
33
1.0
NA
7.31 1.9
7.19 ND
7.15 1.7
6.95 ND
7.23 ND
7.91 2.8
7.99 5.4
8.09 ND
8.31 ND
7.45 ND
7.98 2.3
8.01 2.8
7.62 2.2
8 QQ 1 f*oy i . /
7.90 4.2
6.29 4.8
6.61 1.2
6.66 ND
8.50 3.7
9.03 1.8
8.06 1.5
8.69 1.2
8.15 4.5
8.39 1.1
7.90 ND
6.90 2.0
NA 1.0
NA 500
Ba
23.2
11.6
39.4
6.4
8.9
19.8
30.2
14.5
6.9
8.2
25.2
20.5
38.2
8 C*3
18.4
20.2
11.7
7.1
33.3
7.6
7.6
12.0
24.4
13.1
4.6
17.7
NA
10000
Cr
4.8
1.5
5.5
1.9
2.7
5.3
6.4
2.1
2.2
1.4
5.4
4.3
7.3
2 1.4
3.5
7.7
2.8
3.0
5.8
1.8
1.6
2.9
5.2
2.3
1.3
3.6
NA
500
Cu
1.9
3.2
1.6
1.6
1.1
1.1
1.1
ND
ND
ND
2.6
ND
ND
1.2
1.6
ND
ND
3.5
1.2
2.1
ND
ND
ND
ND
3.3
1.0
2500
Hg
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
UT\NL>
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.25
20
Nl
2.2
ND
1.4
ND
ND
1.3
1.9
ND
ND
1.1
1.9
1.3
3.4
2 ft• U
2.6
2.0
ND
ND
1.5
1.2
ND
ND
1.0
ND
ND
1.7
1.0
2000
Pb
2.0
1.3
1.6
1.5
2.6
2.4
2.3
2.7
3.8
2.3
3.1
2.0
1.3
4.5
2.9
1.1
1.3
5.7b
2.1
2.8
1.7
2.7
1.6
2.5
3.9
1.0
1000
V
14.3
5.8
18.3
8.8
15.5
19.6
19.4
7.1
13.7
6.2
21.2
14.8
19.0
8.5
25.9
7.9
3.5
17.4
13.2
10.0
7.6
16.8
7.6
8.5
14.3
NA
2400
Zn
8.0
7.8
17.1
8.0
9.8
6.7
11.6
3.7
6.2
3.8
10.0
6.6
17.9
17.0
8.3
4.0
1.7
14.8
3.8
8.6
4.3
8.5
5.5
6.0
11.8
•A
5000
Abbreviations:As - Arsenic, Ba » Barium. Cr - Chromium, Cu - Copper, Hg " Mercury, Ni - Nickel, Pb - Lead, V - Vanadium, Zn - Zinc.
ND • Not detected above laboratory detection limit
~ • Not Analyzed
NA - Not Applicable/Not Available
LVW1 - Low-Volume Waste Impoundment No. 1
MCW4 - Metal-Cleaning Waste Impoundment No. 4
TV6 - Treated Waste Impoundment No. 6
*Patch Mix samples from South Bay site
'Symbol Is the Unified System Classification of Soils for Engineering Purposes, ASTM Designation D-2487
CL - Clays, ML - Silts, SC • Clayey Sands, SM • Silty Sands, SP - Poorly graded (well sorted) Bands, SW - Well-graded
. (poorly sorted) sands, GP - Poorly graded gravels, GW - Well-graded gravels
Indicates soil samples which were statistically analvzed as potential extreme values
Project No. 8753249K-ENRP
TABLE 5.2-2
1987 SOIL CHEMICAL ANALYSES
WASTE EXTRACTION TESTS
ENCINA POWER PLANT
(Units - mg/1)
Impoundment
LVWl
LVW2
MCW3
MCW4
TW5
TW6
Boring
8-1
B-2
B-3
B-5
B-6
B-8
B-9
B-10
Approximate
Depth
Interval
Sampled*
(feet)
1.0-1.5
5.0-5.5
0-1.0
1.5-2.5
1.5-2.0
0.5-1.5
2.0-3.0
3.5-4.0
7.0-7.5
5 .'0-5.5
12.5-13.0
19.0-19.5
ASTM*
Soil
Type
(SM)
(SC)
(SP)
(SP)
(SM/SC)
(SW>
(SW)
(SC)
(SW)
(SP)
(SW)
(SC/SW)
Detection
STLC
Sample
I.D.
Number
ENC-P1-B1-2
ENC-P1-B1-5
ENC-P2-B2-1
ENC-P2-B2-2
ENC-P2-B3-2
ENC-P3-B5-1
ENC-P3-B5-2
ENC-P4-B6-3
ENC-P4-B6-4
ENC-P5-B8-4
EKC-P6-B9-5
ENC-P6-B10-7
Limits
Total
Petroleum
Moisture Hydrocarbons
Content (Method pH
(Z)' 418.1) (Units)
_ _ _— __
— — —
ND
— — —__
— ND
ND
_„ „»
—__
__
—
0.05
NA NA NA
As
ND
0.03
ND
0.05
ND
ND
ND
ND
ND
ND
ND
ND
0.02
5.0
Ba
2.3
3.2
1.2
5.0
4.2
1.6
1.0
1.5
ND
0.8
1.0
0.3
0.2
100.0
Cr
ND
ND
ND
t).2
ND
ND
ND
ND
ND
ND
ND
ND
0.1
5.0
Cu
ND
ND
ND
0.3
ND
ND
ND
ND
ND
ND
ND
ND
0.2
25.0
Hs
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.
0.
Nl
0.2
5.3
0.3
13.0
ND
0.2
0.3
ND
0.4
0.2
0.3
0.2
005 0.1
20 20.0
Pb
0.06
0.11
ND
0.36
0.07
0.02
ND
0.03
ND
ND
ND
0.04
0.02
5.0
V
0.3
23.0
0.9
37.2
ND
0.2
0.3
ND
ND
ND
0.2
0.4
0.1
24.0
Zn
0.6
0.2
ND
0.5
ND
NO
ND
ND
ND
ND
ND
0.2
0.1
250.0
Abbreviations:As • Arsenic, Ba • Barium, Cr - Chromium, Cu - Copper, Hg - Mercury, Ni - Nickel, Pb - Lead, V - Vanadium, Zn - Zinc
ND • Not detected above the laboratory detection limit
— • Not «• alyzed
MA - Not ..pplicable/Not Available
LVWl, LVW2 - Low-Volume Waste Impoundments No. 1 & 2
MCW3, MCW4 - Metal-Cleaning Waste Impoundments No. 3 & 4
TW5, TW6 - Treated Waste Impoundments No. 5 & 6
* Depth is calculated from the bottom of the lower liner in impoundment borings and from ground surface in background borings.
Symbol is the Unified System Classification of Soils for Engineering Purposes, ASTM Designation D-2487.
See Table 5.2-1 for explanation of symbols.
Project . 8753249K-ENRP
TABLE 5.3
1986 AND 1987 CROUNDWATER MONITORING DATA
ENCINA POWER PLANT
Paraacter
pH
Units
unit
less
Sampling
Dace
2/86
4/86
9/86
11/86
3/87
5/87
9/87
Detection Field
Limit Blank
6.0
6.7
—
—
—
—
MU-1
7.3
7.1
7.3
7.3
7.3
7.3
7.4
MW-2
7.8
7.5
7.5
7.3
7.7
7.4
7.37/7.37
LVW/MCW
MW-3
8.1
8.0
8.0
8.0
8.0
8.1
7.9
MW-4
7.5
7.4
7.3
7.4
7.6
7.5
7.45
MW-ll(B)
7.8
7.8
7.8
7.9
8.0
7.5
7.94
Conductivity wmhos/ci» 2/86
4/86
9/86
11/86
3/87
5/87
9/87
Coppe mg/L
Nickel mg/L
2/86
4/86
9/86
11/86
3/87
5/87
9/87
2/86
4/86
9/86
11/86
3/87
5/87
9/87
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.05
0.08
0.02
0.01
0.02
0.02
85
110
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
10000
9400
9200
10400
9850
8950
10900
ND
ND
ND
ND
ND
ND
0.04
ND
ND
0.06
ND
0.02
0.03
0.09
4200
5300
5500
6500
5900
5450
5600/5600
ND
ND
ND
ND
ND
0.02
0.04/0.04
ND
ND
0.03
ND
0.02
0.05
0.09/0.09
4100
4300
2950
4500
4300
5000
4150
ND
ND
0.03
ND
ND
ND
0.04
ND
ND
0.02
ND
0.04
0.04
0.09
8300
7800
2640
3900
6150
5350
10750
ND
ND
ND
ND
ND
ND
0.08
ND
ND
0.02
ND
0.02
ND
0.13
12000
12000
10800
11330
9850
11200
10050
ND
ND
ND
ND
ND
ND
0.17
ND
ND
0.04
ND
0.04
0.04
0.13
TW
MW-6
7.3
7.1
7.2
7.2
7.3
7.2/7.2
7.03
8400
9200
8550
8100
7850
6750/6750
7850
0.29
0.12
ND
ND
0.02
0.10/0.09
0.13
1.4
1.4
1.25
1.35
1.57
1.04/1.05
1.34
MW-9
7.7
7.4
7.4
7.5
7.3
7.3
7.16
3800
4500
4000
4250
4250
4175
4150
ND
NO
ND
ND
ND
0.02
0.04
ND
ND
0.05
ND
0.02
0.04
0.13
HU-13
^M
—
—7.0
7.1
6.8
7.0
„
—
—8200
3550
9950
9650
__
_
—ND
ND
ND
0.08
„
—
—ND
0.05
0.04
0.13
MU-IO(B)
7.6
7.7
7.4
7.4
7.7/7.7*
7.9
7.5
3200
3300
3900
4500
3600/3650
3950
4100
ID
ID
IDn>
ND/ND
n>
0.04
m
•D
0.03
HD
0.03/0.03
0.02
0.11
Project no. 8753249K-ENRP
TABLE 5.3 (Concluded)
1986 AND 1987 GROUNDWATER MONITORING DATA
ENCINA POWER PLANT
Parameter
Vanadium
Units
mg/L
Zinc mg/L
Sampling
Date
2/86
4/86
9/86
11/86
3/87
5/87
9/87
2/86
4/86
9/86
11/86
3/87
5/87
9/87
Limit
0.03
0.04
0.02
0.02
01
02
0.01
0.03
0.04
0.01
0.01
0.01
0.01
Field
Blank
ND
ND
—
—
ND
ND
ND
0.083
ND
—
—
ND
ND
ND
MW-1
ND
NO
0.04
ND
0.03
0.04
ND
ND
ND
0.04
ND
0.02
0.02
ND
MW-2
ND
ND
0.06
ND
ND
0.03
ND/ND
ND
0.08
0.05
ND
0.05
0.01
ND/ND
LVW/MCU
MU-3
ND
ND
ND
ND
ND
0.02
ND
ND
ND
0.17
ND
0.41
0.04
ND
MW-4
ND
ND
ND
ND
ND
ND
ND
0.075
ND
0.04ND
0.05
0.02
ND
MW-1 1(B)
ND
ND
0.03
ND
0.03
0.03
ND
ND
ND
0.04
ND
0.01
0.02
ND
TW
HW-6
ND
ND
0.06
ND*
0.02
0.02/0.03
ND
0.23
0.08
0.20
ND
0.10
0.10/0.09
ND
MU-9
ND
ND
0.03
ND
ND
0.03
ND
ND
ND
0.05
ND
0.05
0.04
ND
MW-1 3
w
—
ND
ND
0.02
ND
—
__
ND
0.03
0.01
ND
MW-IO(B)
HD
SO
HO
ND
ND/ND
ND
HD
ND
HD
0.08
ND
0.02/0.22
0.01
ND
Abbreviations: — - Not Analyzed
NS - Not Sampled: Dry Wells
7.7/7.7* • Duplicate samples analyzed
ND • Not detected above laboratory detection limit
LVW/MCW - Low-Volume and Metal-Cleaning Waste Impoundments
TV - Treated Waste Impoundments
(L. - Background well
8 - Concentration revised by SDG&E Laboratory
Note: Detection limits are shown only for parameters that were not detected.
Project No. 8753249K-ENRP
TABLE 6.1
STATISTICAL SIGNIFICANCE TEST RESULTS SUMMARY
1986 AND 1987 SOIL DATA
ENCINA POWER PLANT
Impoundment Boring TPH pH As Ba Cr Cu Hg Ni Pb V Zn
LVW1
LVW2
MCW3
MCW4
B-l
B-2
B-3
B-4
B-5
B-6
LVW/MCW*MW-1
through
MW-5
NA NA
TW5
TW6
B-7
B-8
B-9
B-10
TW*MW-6
through
MW-9
NA NA
Abbreviations:TPH - Total Petroleum Hydrocarbons, As = Arsenic, Ba =
Barium, Cr • Chromium, Cu » Copper, Hg = Mercury,
Ni = Nickel, Pb = Lead, V - Vanadium, Zn = Zinc
LVW = Low-Volume Waste Impoundment
MCW = Metal-Cleaning Waste Impoundment
TW - Treated Waste Impoundment
+ = Statistically significant difference
= No statistically significant difference
(+) = Indicates statistical significance for an extreme
value in the boring
> = Indicates pH value was significantly elevated
NA = Not analyzed
* = 1986 Monitoring Well Boring Data
Project No. 8753249K-ENRP
TABLE 6.2
Parameter MW-1
STATISTICAL SIGNIFICANCE TEST RESULTS SUMMARY
1987 GROUNDWATER MONITORING DATA
ENCINA POWER PLANT
LVW/MCW
MW-2 MW-3 MW-4 MW-6
TW
MW-9 MW-13
Cu
Ni
V
Zn
Abbreviations:
Cu
Ni
V
Zn
Copper
Nickel
Vanadium
Zinc
+ - statistically significant difference
- « no statistically significant difference
LVW/MCW » Low-Volume Waste and Metal-Cleaning Waste
Impoundments
TW • Treated Waste Impoundments
a - Indicates parameter was statistically significant in
1986 and 1987.
Project No. 8753249K-ENRP
TABLE 7.2-1
SOIL CHEMISTRY COMPARED TO
NORMAL RANGES IN WESTERN U.S. SOILS
(mg/kg)
Parameter
Arsenic
Barium
Chromium
Copper
Mercury
Nickel
Lead
Vanadium
Zinc
Maximum Concentration
At Encina Site Adjacent
or Beneath Impoundments
7.7
128
27
98
ND
214
8.3
530
320
U.S. Soils
Mean (Range)
6(0.1-40)
500(100-3000)
100(5-3000)
20(2-100)
0.03(0.01-0.3)
40(10-1000)
10(2-100)
100(20-500)
50(10-300)
Data from: Bowen, H.G.M.; 1986: Trace Elements in Biochemistry. New York:
Academic Press, Inc. Concentrations are for oven dried soils, excluding
soils near mineral deposits.
Project No. 8753249K-ENRP
TABLE 7.2-2
GROUNDWATER QUALITY DATA AND
DRINKING WATER STANDARDS
(mg/1)
Maximum Concentration Drinking Water
Parameter
Arsenic
Barium
Chromium
Copper
Mercury
Nickel
Lead
Vanadium
Zinc
in Downgradient Wells
0.008
0.21
0.06b
0.29
0.0029
1.57
0.12
0.06
0.41
Standards
0.05
1.0
0.05b
1.0
0.002
None
0.05
None
5.0
Excludes monitoring wells MW-5 and MW-12.
Groundwater samples were analyzed for total chromium; drinking water
standard is for hexavalent chromium.
CMarshack, "Update of Water Quality Goals," California Regional Water
Quality Control Board, Central Valley Region, September 18, 1987.
Includes primary and secondary maximum contaminant limits.
Project No. 8753249K-ENRP
TABLE A-2
1986 SOIL CHEMICAL ANALYSES - ME1ALS*
MONITORING WELL BORINGS
ENCINA POWER PLAN!
LVW/MCU
Parameter HW-1
(»g/kg) El-2
Metals
Aluminum 4,500
Arsenic 0.82
Barium 72
Beryllium 0.22
Cadmium
Total
Chromium 14
Copper 98
Lead
Mercury
Nickel 5.0
Vanadium 19
Zinc 150
Geologic Fill
Formation
Sample 2.8
Elevation
(ft, MSL)
Sample Type V
MW-2 MW-3 MW-4
E2-2 E2-5 E2-11U E3-2
4,900 5,800 8,100 5,300
0.81 0.56 -- 0.76
43 76 77 48
0.17 0.28 0.52 0.15
-.
7.4 10 9.0 10
17 20 27 8.8
--
.-
3.4 3.9 5.7 3.9
17 9.9 22 20
47 86 41 42
Fill Fill Fill Fill
20.0 8.1 -3.0 12.8
V F S V
(above
perched)
E3-3" E4-2
3,800 5,900
-
36 63
0.006 0.31
.-
7.4 7.2
SO 14
--
-
5.7 3.4
30 15
31 320
Fill Fill
8.8 9.8
V V/S
(below
perched)
MW-5 MW-1KB) MW-12(B)
E5-3 £5-6 Ell-2 E12-2
4,300 1,200 6,900 4,500
0.96
58 8.7 19 24
0.29
"
27 5.2 9.2 5.8
5.3 1.8 13 5.2
—
.-
6.5 -- 2.4* 1.3
13 8.3 37 20
15 6.3 16 11
Fill Ql Fill Fill
0.8 -10.7 9.6 9.8
V S V V
TV
MW-6
E6-3
28
4.6
2.2
14
9.8
Qby
26.1
E6-5
MW-7
E7-3
MW-8 MW-9
E8-4 E8-8 E9-3 E9-7
mi-lO(g)
EU>-3 E10-7
3,600 2,900 3,300 2,300
24
3.8
1.8
1.3
9.6
15
I*b
15.1
14
3.4
31
21
5.0
1.7
8.2 17
65 4.8
Qby Qby
4,500
1.9
15
0.26
6.7
14
2,000 5,100 1,400 3,200
25 18
0.28
3.4 4.9
1.5 1.6
8.4
J7
18
Tab
1.2
9.5
7.6
28.4 27.0 20.5 25.0
15 40
— 0.20
4.S 3.8
1.1 2.0
2.1
5.8
9.8
Tab
5.0
1.2 1.2
22 7.6
6.1 9.4
Q*r Tab
44.6 2S.6
Sanplei collected January 15 through 29, 1986, and analyzed In March 1986, except where noted.
Samples collected In January, 1986, and analyzed In February, 1986.
Ql • Quaternary lagoonal depoalta; Qby - Quaternary Bay Folnt Formation (terrace deposits); Tab - Tertiary Santiago Fonatlon.
V • Vadoie Zone, F • Perched Water Zone, S - Saturated Zone.
Concentration reported Incorrectly aa "not detected" In HAR.
•- • Not detected.
LVW/HCW - Lov-Voluae Watte and Metal-Cleaning Waate Impoundment*.
TH - Treated Waste lapoundnents.
(B) • Background well borings.
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ATTACHMENT 4-2
ESTABLISHMENT OF BACKGROUND LEVELS
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ESTABLISHMENT OF BACKGROUND LEVELS
INTRODUCTION
To determine whether soils surrounding the hazardous
waste surface impoundments have been contaminated by the
impoundments, the concentrations of selected parameters in the
suspect soils will be compared to concentrations of the same
parameters in uncontaminated background soils. Thus, for each
parameter, it is necessary to establish a background level. The
methodology that will be followed to establish these background
levels is described in this attachment.
Statistics are used throughout both State and Federal
hazardous waste regulations to set standards, determine whether
wastes are hazardous and evaluate groundwater monitoring data to
determine whether contamination has occurred. However, there is
no regulatory method for evaluating whether a site has been
contaminated above background levels but below hazardous levels.
There is not even a method for exactly determining background
levels. This attachment will evaluate a statistical approach to
set background levels or standards for site remediation or closure
efforts.
This attachment has two major parts. The first is an
evaluation of statistical approaches currently employed by
regulators to determine whether a waste is hazardous or
groundwater is contaminated. The second part is a description of
a new statistical approach for establishing background levels.
The attachment also includes information on selecting the number
of background samples, dealing with analytical limitations and
using data transformations for statistically non-normal data.
Examples using this new method will also be presented.
EXISTING STATISTICAL METHODS
Two existing statistical methods used in applying
hazardous waste regulations have been suggested by some regulators
as possible methods for establishing background levels for site
decontamination strategies. The first method is from "Test
Methods for Evaluating Solid Waste," SW-846, and is often used to
determine whether a waste is hazardous. The second method is the
Cochran's Approximation to the Behrens-Fisher Student's t-test
which is used to determine whether groundwater contamination has
occurred from a hazardous waste unit. The two methods are
described below, and reasons are presented to explain why they are
not appropriate for determining if contaminant concentrations are
statistically greater than background levels.
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Hazardous Waste Approach
Section One of SW-846 describes a statistical method for
determining whether a waste is hazardous. An example is presented
of a pond that is filled with sludge containing barium. The
sludge is sampled and analyzed to determine whether the EP
toxicity level of 100 mg/1 for barium is exceeded. From the
analytical data the mean and the standard deviation of the sample
population are calculated. The Student's t-test is then used to
calculate the confidence interval of the true population mean.
The sludge is considered hazardous if the upper bound of the
confidence interval for the population mean exceeds the EP
toxicity level (100 mg/1 for barium).
It is important to understand what the Student's t-test
is and how it is being applied. The Student's t-test determines
the upper and lower bounds of the true population mean, based on
the sample mean and sample standard deviation, at a given level of
confidence. It assumes that both the entire population and
samples are normally distributed. The larger the certainty
required, the farther the upper and lower bounds of the confidence
interval are from the sample mean. As more samples are taken from
a normally distributed population, the smaller the confidence
interval becomes. As the number of samples approaches infinity,
the upper and lower bounds of the confidence interval converge at
the point where the population mean and sample mean become equal.
In applying this method to a waste, the regulatory
threshold for a waste is compared to the upper bound of the
confidence interval of the population mean at a given level of
confidence. In effect, it is an attempt to compare the average
concentration of a contaminant to the regulatory level without
taking an infinite number of samples. This is done by relying on
statistics to establish the highest average concentration which
could actually exist, with an acceptable level of confidence,
based on the limited sampling. As the sample size increases, the
maximum probable concentration would decrease as the confidence
interval narrowed. This was demonstrated quite well in the
example in SW-846. More samples were taken until the regulatory
level was found to be greater than the upper bound of the
confidence interval, thus indicating that the sludge was not
hazardous at the 90% level of confidence.
In site remediation or closure projects we are comparing
one sample per segment of soil to the background concentrations to
see if the whole segment is contaminated. If a large number of
background samples was taken from a normally distributed
population, the confidence interval for the true mean would be
quite small. With larger and larger sample sizes, the upper bound
of the confidence interval would decrease, approaching the
population mean, until finally they were equal. At this point, if
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a sample concentration was compared to the upper bound, it would
have a fifty percent chance of exceeding it, even if contamination
had not occurred. Consequently, this approach might lead to
erroneously excavating uncontaminated background soils up to
fifty percent of the time.
In summary, the Student's t-test is not appropriate for
determining whether contaminant concentrations in soils exceed
background concentrations. Its best use is to compare a set
value, such as a regulatory level, to the probable average
concentration of a waste.
Groundwater Contamination Approach
California (23CCR2556(h)) and Federal (40CFR264.97(h))
regulations require use of Cochran's Approximation to the
Behrens-Fisher (CABF) Student's t-test to evaluate whether
groundwater contamination from a hazardous waste management unit
has occurred. It is evaluated below as a decision-making tool to
determine, with statistical validity, if concentrations in
potentially contaminated soils exceed the concentrations in
background soils.
The CABF Student's t-test statistically compares two
sets of samples to determine whether they are from the same
population or from two different populations. The t-test
determines whether there is an overlap in the confidence
intervals of the true population means of the two data sets at a
given level of confidence.
In a groundwater detection monitoring program,
upgradient groundwater is sampled a sufficient number of times (a
minimum of sixteen samples) to establish background statistics for
each monitoring parameter. Once monitoring begins, four samples
are taken quarterly from each upgradient and downgradient well.
The mean and standard deviation of each parameter are computed for
each well. This data is then compared to the original background
values using the CABF Student's t-test to see whether the new
samples are from the same population as the old. If they are not,
groundwater contamination is assumed to have occurred, and the
wells are resampled for confirmation of the contamination.
Application of the CABF Student's t-test to site
remediation or closure projects would usually be very costly and
time consuming because a large number of samples are required. If
analytical costs for a soil segment exceed the costs to excavate
that segment and dispose of it as a hazardous waste, it is
economically advantageous to excavate rather than test. The CABF
requires a minimum of four samples from each soil segment for
comparison to background. To make this approach economically
feasible, the soil segments should be large enough so that testing
a segment is cheaper than removing and disposing of it.
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However, migrating contaminants are usually spatially
concentrated rather than dispersed. With the large number of
samples that are required per segment, only a relatively small
number of soil segments are necessary before exceeding the total
number of samples that are economically feasible. This would
increase the size of each segment, which would decrease the chance
of detecting contamination.
The CABF Student's t-test would be a cumbersome decision
tool. In the end, each concentration value would be separately
evaluated to see whether it exceeds background. Rather than this
approach, the statistical approach described in the next section
is proposed for determination of the extent of contamination.
PROPOSED STATISTICAL APPROACH
This part of the attachment presents an alternative
statistical approach for establishing background levels that will
be used to determine if soil is contaminated. The first section
describes a statistical basis for establishing background levels.
The remaining sections describe how to implement it. They
describe how to select the number of background samples, deal with
analytical limitations and transform statistically non-normal
data. Some examples of this method are also presented.
Background Levels
The goal of this statistical approach is the same as the
regulatory goal for evaluating groundwater monitoring data: the
method provides "a reasonable balance between the probability of
falsely identifying a significant difference and the probability
of failing to identify a significant difference..." (23CCR2555).
It is assumed that the population of true background
concentrations has a normal distribution with a mean, M, and
standard deviation, S. For a normally distributed population, the
probability that a random sample will have an actual value less
than or equal to a given value can be found using the distribution
function F(x). From a table for the normal distribution function,
it can be seen that there is a 50% chance that a random sample
will be less than M, a 84.13% chance that a sample will be less
than M + S, a 97.73% chance of it being less than M + 2S and a
99.87% chance of it being less than M + 3S.
For this closure, it is proposed that each background
standard, BL, be established at three standard deviations above
the mean; that is,
BL = M + 3S. (1)
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To evaluate the reasonableness of this value for
background, assume that sixteen samples will be taken of the soils
underlying one pond and twenty-five analyses will be run on each
sample. This means that four hundred values will be compared to
background. If no contamination has occurred, the probability, P,
of an individual parameter exceeding its background standard would
be about 0.13 percent (P=l.0-F(x=BL)). However, for 400
parameters, the cumulative probability, C, of one or more
uncontaminated samples exceeding its background standard would be
about 41 percent (C=l.0-(F(x=BL))3, where q=400). Therefore, even
if no contamination has occurred at the site, there is almost an
even chance that contamination would be falsely indicated.
Another way of looking at the reasonableness of this
approach is to compare the maximum possible value of the
background level to hazardous levels. For normally distributed
data, the coefficient of variation, CV, must be less than or equal
to 1.0. Since CV is equal to S/M, the largest permissible value
of S is M. Substituting M for S into equation (1) , the maximum
value for background, BL, is four times the mean concentration.
Background soil concentrations are usually orders of magnitude
below hazardous concentration levels; thus, the maximum background
levels would be well below any environmental or health threat
level.
The above formula for background standards uses the the
statistics of the population and must be converted to those of the
sample. For the population standard deviation, S, the sample
standard deviation, s, is recommended. For the population mean,
M, it is proposed that the sample mean, m, be used. Substituting
these values for M and S, the background level, BL, is equal to
three sample standard deviations above the sample mean:
BL = m + 3s. (2)
A sample calculation for determining the background
standards is given in Example 1.
Minimum Sample Size
To calculate the number of samples required to establish
background, a rather involved statistical approach has been used.
For a given number of background samples, n, taken from an
infinite population, each with concentration, x(i), where i=l to
n. The sample mean concentration, m, is defined as:
1 n
m = 3C x (i) . (3)
n i = l
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The square of the approximate standard deviation, s, used for
small sample size is:
1 n
s2 = — £ (x(i) - m)2 (4)
n-1 i=l
If the data is assumed to be normally distributed,
statistical analysis applicable to a normal population can be
utilized. For a 100 (1-a) percent confidence interval for the
population mean, M, given the sample mean, m, and the sample
standard deviation, s, the Student's t-distribution yields:
Pr {-t < (M-m) yTn < t} = 1-a (5)
s
Since the value of t is fixed by "a" and "n", the
difference between the sample mean and the true population mean
lies within a given range for a given degree of probability.
Rearranging the inside yields:
ts ts
(6)
This means that there is a (1-a) 100% confidence that
the population mean, m, is between the two extremes. Letting CI
equal the confidence interval of the population mean at 1-a
probability yields:
ts
CI = m +_ JTT (7)
While the above equation is generally used to calculate
the confidence interval of the population mean after sampling has
occurred, it can also be used to calculate the number of samples
required to obtain a given confidence interval for an assumed set
of data. The first step is to select a confidence interval for
the population mean. The sample mean plus and minus one standard
deviation was chosen as a reasonable interval. Thus, the lower
bound is equal to m - s, and the. upper bound is equal to m + s.
Substituting the value for the upper bound into Equation (7)
yields the equation:
m + s = m + st (8)
For Equation (8) to be valid, t /V"n must be equal to
1.0. For a given 1-a probability of the population mean which is
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within the given confidence interval, there is only one
combination of n and t (from a Student's t-distribution table)
which will solve equation (8) . Thus/ a confidence interval must
be selected.
In keeping with current regulatory practice for the
t-test, the 95th percentile for the upper bound was selected.
(This is equivalent to 90% confidence level for a two-sided test.)
For n samples, the degree of freedom, df, is equal to n-1. From a
Student's t-distribution table, it was found that six samples
would be required.
In summary, for a 95% probability of having the true
population mean not exceed twice the sample mean for a normally
distributed data set, a minimum of six samples would be required.
If the standard deviation is actually less than the sample mean,
then the confidence interval for the population mean would be even
smaller.
Analytical Limitations
This method to determine the background level, BL,
assumes that all of the data for a given parameter are measurable
and quantifiable; that is, they are above the method detection
limit, MDL, for that parameter. This section addresses how the
background level for a parameter should be calculated when some or
all of the background concentrations are below its MDL.
The simplest case is when all of the background samples
are below the parameter's MDL. If this happens, the background
level will be assumed to be equal to twice the MDL for that
parameter. This value was chosen by assuming that both the mean
and standard deviation are equal to one-half the MDL.
The more difficult situation arises when some of the
data are below the MDL and some are above it. The problem is how
to best handle the data to statistically describe its
distribution in terms of the sample mean and standard deviation.
The graphic approach used by McCarty et al. (2,3) will
be used as follows:
1. Arrange the data in descending rank order and
calculate the probability distribution function, F,
for each concentration which is above the MDL:
F[x(i)] = (i - 0.375)/(n + 0.25),
where x(i) is the i-th largest observed value from
sample size n.
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2. Linearize the probability function by using the
formula which approximates a normal distribution:
P(i) = 4.91 * {{F[x(i) ] }0.14 - [I - F[x(i) ] }°-14}
3. Plot the concentrations versus P(i) for the values
above the MDL.
4. Perform a least squares fit on the data above the
MDL. The zero intercept will be the mean, m, and
the slope will be the standard deviation/ s.
Example 2 shows how this method would be used when some of the
data is below the MDL.
Data Transformations
In the above discussion, it was assumed that the data
would be normally distributed. Current regulatory practices
assume the data is from a normal population if the coefficient of
variation, CV(=s/m) is less than or equal to one.
Each data set will be checked to see if it meets this
requirement. If it does not, various transformations will be
tried to normalize the data. Transformations which will be tried
include log, square root and arcsin. The normalized mean and
standard deviation will be determined for the transformed data and
the coefficients of variation checked to see if the transformed
data is now normal.
If the transformed data is normal, the background level
will be determined for the transformed data. By taking the
anti-transform, the true background level, BL, can be found.
Example 3 demonstrates how the transform process would work using
the log-transformation.
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1.
2.
3.
REFERENCES
Benjamin, J.R. and C.A. Cornell, Probability, Statistics, and
Decision for Civil Engineers, McGraw-Hill, NY, 1970.
McCarty, P.L., M. Reinhard, C. Dolce, H. Nguyen, and D.G.
Ar go, Water Factory 21; Reclaimed Water, Volatile Organics,
Virus, and Treatment Performance, EPA-600/2-78-076, 1978.
McCarty, P.L., M.
Sutherland, T.
Reinhard,
Everhart,
J. Graydon, J.
and D.G. Argo,
Schreiner, K.
Wastewater
Contaminant Removal for Groundwater Recharge at Water Factory
21, EPA-600/2-80-114, 1980.
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EXAMPLE 1: BACKGROUND LEVEL DETERMINATION
1. Assume the following background values.
a. X-values: 89, 90, 87, 96, 93, 113. n=6
2. Determine the sample mean, m:
1 n 89+90+87+96+93+113
m = — £ x(i) =n 1=1 6
m = 94.7
3. Determine the sample standard deviation, s:
1 n
s2 = £T (x(i)-m)2
n-1 1=1
s2 = 96.7
s = 9.5
4. Check the coefficient of variation, CV, to see if the data
are normal.
CV = s/m = 9.5/94.7 = 0.10
CV <_ 1.0; therefore, the data are normal.
5. Calculate the background level, BL:
BL = m + 3s
BL = 94.7 + 3(9.5)
BL = 123.2
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EXAMPLE 2: SOME DATA LESS THAN THE MDL
1. Use the data from Example 1, but assume the MDL = 90.
X-values: <90, 90, <90, 96, 93, 113. n=6.
2. Rearrange the data in descending rank order. Determine
F(x(i)) and P(x(i)) for values above the MDL.
6
5
4
3
2
1
113
96
93
90
<90
<90
0.90
0.74
0.58
0.42.
1.28
0.64
0.20
-0.20
Plot x(i) vs. P(x(i)) and do a least squares fit of the data.
Determine the 0-intercept, which equals m, and the slope,
which equals s. (See Figure 1 for graphical representation.)
m = 0-intercept =90.6
s = slope = 15.4
Check the coefficient of variation, CV.
CV = s/m = 15.4/90.6 = 0.17
CV £ 1.0; therefore, assume normal distribution.
Calculate the background level, BL.
BL = m + 3s = 90.6 + 3M15.4)
BL = 136.8
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BACKGROUND LEVEL DETERMINATION WHEN
SOME DATA ARE BELOW MDL
140
130 —
120 —
110 —
100 —
90 —
BL-136.8
MOL-90.0
Least Squares FK
m - Onntercept - 90.6
• - slop* . 15.4
-3.0 -2.0 -1.0 0.0 +1.0 +2.0 +3.0
xfiVm
s
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EXAMPLE 3: LOG TRANSFORMATION OF DATA
1. Use the data from Example 1.
X-values: 89, 90, 87, 96, 93, 113. n=6.
2. Transform the data by taking the log of each data point,
a. Log X-values: 1.95, 1.95, 1.94, 1.98, 1.97, 2.05
3. Calculate the mean of the transformed x-values.
1 n
mT = £ log(x(i))
n i=l
mT= 1.97
4. Calculate the standard deviation of the transformed x-values.
ST = 0.04
5. Check the efficiency of variation, CV^, of the transformed
data.
CVT = sT/mT = 0.04/1.97 =0.02
CVT £ 1.0; therefore, assumed normal.
6. Calculate the transformed background level, BLip
BLT = mT + 3sT = 1.97 + 3(0.04) = 2.09
7. Determine the actual BL by taking the anti-transform, which
is the anti-log.
BL = 1QBLT = 1Q2.09
BL = 124.
/MITTELhMUSER L.' corpora hon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RO
ATTACHMENT 4-3
DEIONIZED WATER WASTE EXTRACTION TEST RATIONALE
/MITTELH>IUSERcorporation
SDG&E 4-3-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RO
DEIQNIZED WATER WASTE EXTRACTION TEST RATIONALE
Soluble metal ion concentrations may be measured during
closure to predict if contaminated soils will adversely impact
surface or groundwaters. The soluble concentrations will be
measured in deionized water extracts of background soil samples
and of soil samples collected beneath the impoundments. To
prepare the extracts, the California Waste Extraction Test
procedures (22 Cal. Code of Regulations, Section 66700) will be
followed except that deionized water will be substituted for the
standard citric acid buffer solution.
The impact of metals contamination on ground or surface
water depends on the concentrations that migrate under actual
site conditions. On-site soil pH values are expected to be
slightly alkaline, in the range of 7 to 10. In this range of pH
values the metals will generally be relatively insoluble
hydroxides, carbonates or other salts and will, in effect, be
fixed in the soil. Consequently, even if total concentrations
exceed the background standards, the metals may not be soluble
under the pH conditions at the site.
As mentioned above, deionized water will be substituted
for citric acid in the Waste Extraction Test (WET) to extract
soluble metal ions. Use of deionized water simulates on-site
conditions in the saturated and unsaturated zones more closely
than citric acid. In the standard WET, the low pH and moderate
ability of citric acid to complex metal ions both contribute to
solubilizing metal ions. In the future, the on-site soil pH is
expected to be greater than the value of 5 used in the standard
WET procedure. Moreover, there should be no appreciable
concentrations of complex-forming organics in the soil, from, for
example, decomposition of organic wastes. Even if metal ions
leak out of the impoundments, they are likely to be fixed in the
soil. Use of deionized water as the extraction solution in the
WET procedure will most closely simulate site conditions with
regard to metal ion mobility.
A further, practical advantage of the deionized water
waste extraction test procedure (DW-WET) is the familiarity of the
procedure among California hazardous waste laboratories and the
ready availability of the extraction solution in those
laboratories.
Following the methodology presented in the draft
guidance document, "Waste Classification and Cleanup Level
Determination," by Jon Marshack of the Central Valley Regional
Water Quality Control Board, soluble concentrations of
contaminated soils can be used to predict the impacts of migrating
contaminants on surface and groundwater quality. Mittelhauser
Corporation has successfully used this methodology in a surface
impoundment closure. In that project, it was shown that although
/VHTTELH4USERcorporahon
SDG&E 4-3-2 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RO
contaminated soils had total metal concentrations greater than
site-specific cleanup levels, soluble metals were sufficiently low
to not adversely impact water quality.
In the Encina closure, if total metal concentrations
exceed the background standards established for total metals,
soluble concentrations may be measured. The soluble
concentrations will be compared to applicable water quality
standards multiplied by an environmental attenuation factor.
Using criteria explained in the Marshack document, an attenuation
factor of 10 to 100 would be appropriate for the Encina site due
to the depth to groundwater and annual rainfall. Appropriate
water quality standards might be health based standards, such as
drinking water standards or maximum contaminant levels (MCLs), the
soluble concentrations in background soil, groundwater
concentrations or perhaps other applicable standards.
vcorporation
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RO
ATTACHMENT 4-4
CLOSURE STEP DECISION DIAGRAM
STEP 1
IMPLEMENT CLOSURE PLAN
AND NOTIFY AGENCIES.
PREPARE SITE SPECIFIC
HEALTH AND SAFETY PLAN
STEP 2
TREAT AND REMOVE
ALL WASTE FROM UNITS
STEP 3
DOCUMENT ALL
ASSOCIATED PIPING
STEP 4
WASH THE UNER
BY HYDROBLAST1NG OR
STEAM CLEANING
SAMPLE WASHING
RESIDUALS AND ANALYZE
FOR pH AND TTLC
ARE RESIDUALS
HAZARDOUS
WASTE ?
CAN THE RESIDUALS
BE TREATED IN THE
WASTEWATER TREATMENT
SYSTEM
TRANSFER TO
WWT SYSTEM
(CONT. WITH
STEP 5)
DISPOSE Of RESIDUALS OFF-SITE
STEP 5
FLUSH ALL
ASSOCIATED PIPING
TEST FLUSH WATER FOR pH
AND TTLC METALS
IS THE
FLUSH WATER
HAZARDOUS ?
STEP 6
INSPECT LINER AND
DOCUMENT AREAS OF CONCERN.
IDENTIFY UNER SAMPLING
LOCATIONS AS OUTLINED
IN ATTACHMENT 4-5
IDENTIFY AND COLLECT A MINIMUM
OF- 2 ADDITIONAL BACKGROUND
SOIL SAMPLES AND ANALYZE
FOR pH. TPH AND TTLC
STEP 7*8
SAMPLE THE LINER. GRAVEL.
AND UNDERLYING SOIL AS
OUTLINED IN ATTACHMENT 4-5
ANALYZE THE SAMPLES
FOR pH. TPH, AND TTLC
PER ATTACHMENT 4-5
CONTINUED ON PAGE 2
PAA
KYM
°*1t 12/05/8E
»** NONE
ATTACHMENT 4-4
CLOSURE STEP DECISION DIAGRAM
PAGE 1 OF 2
SDG4E ENC1NA POWER PUNT
0 ""1 0800702
"• "°P1080 1080-00-004
CONTINUED FROM PACE 1
YESARE LINER RESULTS
GREATER THAN THE TTLC
OR STLC LIMITS 7
DOES ON-SITE DISPOSAL
OF LINER CONSTITUTE
A REGULATED LANDFILL 7
LINER REMAINS
ON-SITE
REMOVE AND DISPOSE OF
LINER AS AN INERT
WASTE
REMOVE AND DISPOSE OF
LINER AS A HAZARDOUS
WASTE
ARE SOIL RESULTS
GREATER THAN TTLC
LIMITS 7
ARE TTLC RESULTS
GREATER THAN 10 TIMES
STLC LIMITS 7
ARE SOIL RESULTS
GREATER THAN CALCULATED
BACKGROUND 7
YES
YES ARE STLC
RESULTS GREATER
THAN LIMITS 7
YES
SOILS ARE HAZARDOUS OR
CONTAMINATED WASTE. COMPLETE
ADDITIONAL SAMPLING TO DEFINE
VERTICAL AND HORIZONTAL
EXTENT. IF NECESSARY.
SITE
DECONTAMINATED
ASSESS POTENTIAL
ENVIRONMENTAL IMPACT
STEP 11
BACKFILL
STEP 9
REMOVE HAZARDOUS OR
CONTAMINATED SOIL
STEP 12
PREPARE CLOSURE
CERTIFICATION REPORT
STEP 10
COLLECT AND ANALYZE
CONFIRMATION SOIL SAMPLES
PAA
KYU
JLZ/06/Bi
ATTACHMENT 4-4
CLOSURE STEP DECISION DIAGRAM
PAGE 2 OF 2
SDG&E ENCINA POWER PLANT
1080-00-004
/VIITTELH/1USER tcorporahon
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
ATTACHMENT 4-5
SAMPLING AND ANALYSIS PLAN
/MITTELH>4USERcorpora hon
SDG&E 4-5-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
ATTACHMENT 4-5
SAMPLING AND ANALYSIS PLAN
A. INTRODUCTION
San Diego Gas and Electric Company (SDG&E) is closing
six surface impoundments at the Encina Power Plant. The surface
impoundments were used to collect wastewaters prior to treatment
and/or discharge. This sampling and analysis program will be
performed to determine proper handling or disposal methods for
flush water, surface impoundment washing residues, liners (asphalt
and gravel) and soil.
The analytical results will be used in conjunction with
the Site Cleanup Strategy presented in Section 4.2 to determine
the waste categories for the asphalt concrete and soils. Based on
the analytical results, the materials will be classified as
hazardous, designated or inert. Hazardous and designated wastes
will be transported off-site for appropriate disposal. Materials
classified as inert, concentrations meeting background criteria,
may be left in place at the site or disposed of at a Class III
facility.
B. ANALYTICAL PARAMETERS
Samples collected during the implementation of this
sampling and analysis plan will be analyzed for the following
eleven parameters:
Total Petroleum Hydrocarbons (TPH)
pH Mercury
Arsenic Nickel
Barium Lead
Chromium Vanadium
Copper Zinc
The analytical procedures for these parameters are
identified in Section H of this attachment. The rationale for the
selection of these parameters is presented in Section 4.2.2.
C. VISUAL OBSERVATION
The surface impoundments will be inspected for any
visible cracks, discoloration, or other signs of leakage or
deterioration. Before the inspection, all wastes will be removed
from the impoundments. The asphalt concrete liner will be washed
using a hydroblaster or steam cleaned. The cleaning residuals
will be transferred to either a portable tank or to the new
wastewater treatment system.
/MITTELH4USERcorporation
SDG&E 4-5-2 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
After removing all of the wastes and cleaning the
asphalt concrete, the surface will be visually inspected by two
people such as the plant engineer or inspector, environmental
coordinator, registered geologist, engineering geologist or a
qualified contractor. The inspectors will look for visible cracks
in the asphalt concrete or areas of erosion, pitting, or spalling.
The approximate length, width, and depth of any significant cracks
will be recorded by the inspectors. On a plot plan of the
impoundments, the size and location of any significant areas of
erosion, pitting, or spalling found during the inspection will be
recorded. A photographic record of the inspection will be kept
which pictures problem areas encountered.
D. ASPHALT CONCRETE LINERS AND GRAVEL SAMPLING AND ANALYSIS
After the impoundment has been cleaned and visually
inspected, samples of the asphalt concrete liners (upper and
lower) and gravel between the liners will be taken to classify
the materials for disposal methods. Each impoundment will be
divided into quadrants and one core sample will be taken within
each quadrant, four sample locations per impoundment. The sample
will be taken at areas of concern identified by the inspection or
at a randomly selected point within a quadrant. If no areas of
concern were identified, the quadrant will be divided into
approximately 20 numbered squares, and a random number will be
selected using a random number generator such as those built into
hand-held calculators.
Asphalt samples will be obtained using a coring
machine or saw while gravel samples will be obtained using a
trowel or shovel. A total of twelve samples, four upper liner,
four gravel and four lower liner, will be taken for each
impoundments.
The samples will be analyzed for total and soluble
concentration of metals to determine whether the liner materials
are a hazardous waste. If any TTLC or STLC values are exceeded,
the corresponding material will be deemed hazardous and disposed
as such; if not, the materials will be left on-site or disposed of
as a non-hazardous, solid waste.
E. LIQUID SAMPLING AND ANALYSIS
The flush water and the residual from washing the
surface impoundments will be sampled to determine the appropriate
disposal method. Samples will be collected using a plastic or
glass container from the surface impoundments. The samples will
be analyzed for pH, oil and grease, and metals. The flush water
and washing residuals will be processed through the plant's
on-site wastewater treatment systems or will be disposed of
off-site.
/V1ITTELH>1USER ucorporation
SDG&E 4-5-3 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
F. SOIL SAMPLING AND ANALYSIS
Soil samples will be collected and analyzed to determine
if contamination exists underlying the surface impoundments by
comparing the results to background levels. The analyses will also
be used to categorize any soil which is contaminated so that it
may be properly disposed.
The results of the RI indicated that there is
contamination underlying LVW 1 and 2 while there is no
contamination underlying MCW 3 and 4 and TW 5 and 6. Based on
these results, different soil sampling and analysis strategies
have been developed for the different surface impoundments.
Background Samples
Four soil borings will be completed for background soil
sampling; two borings in the area of the LVW and MCW impoundments
and two in the area of the TW impoundments. These borings will be
located near the impoundments/ close enough to have the same soil
characteristics, yet far enough away to be unaffected by any
possible leaks from the ponds. The exact locations will be
selected in the field during the implementation of the closure
plan. Consideration will be given to accessibility, utilities, and
likelihood of not being contaminated.
Samples will be obtained at 2 foot intervals starting at
the surface and extending to groundwater. A minimum of four
samples from each boring representing each soil type will be
selected. They will be randomly selected from boring samples of
similar soil classification, more than four exists.
MCW-3 and -4 and TW- 5 and -6
Since the results of the RI indicated no significant
soil contamination underlying these surface impoundments, limited
soil sampling will be completed for these impoundments. Each
surface impoundment will be divided into quadrants and one soil
boring will be completed within each quadrant. The exact location
of the boring will be based on the inspection of the asphalt
liner. If the inspection identified a location of concern within
the quadrant, the sampling will be completed in that location.
When several areas of concerns were identified, the area which
seemed to have the largest impact on the integrity of the
impoundment will be chosen. If the inspection did not identify
any areas of concern, then the sample location will be randomly
selected. The area will be divided into approximately 20 numbered
squares and then a random number will be selected using a hand
held calculator or equivalent method to select a random number
between 1 and 20.
/MITTELH/IUSER vcorporation
SDG&E 4-5-4 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
Samples will be obtained at 2 foot intervals starting at
the surface and extending to groundwater for locations where a
drill rig can be used. If the sample location is located on a
side wall of the impoundment, a hand or power auger will be used
and samples will be obtained at 2 foot intervals starting at the
surface and extending to 6 to 10 feet.
LVW- 1 and -2
The results of the RI indicated that there is soil
contamination underlying LVW 1 and 2. This contamination may be
from the operations of an abandoned pond that underlies these two
surface impoundments and not from the operations of the existing
surface impoundments, Figure 4-5-1. Tables of the results for
soil samples completed for the RI are presented in Tables 5.2-1,
5.2-2 and A-2 found in Attachment 4-1.
Soil analytical results for B-l in LVW-1 showed high
concentrations of metals approximately 5.5 feet below the surface
of the impoundment. B-2 in LVW-2 showed the same high levels of
metals that B-l showed at approximately 2.5 feet below the surface
of the impoundment. However, the results for B-3 in LVW-2 showed
no contamination above background. B-3 is approximately 60 feet
from B-2.
During the installation of monitoring wells MW-1, 2, 4
and 5 which are on the perimeter of LVW-1 and 2, soil samples were
analyzed. The results of the samples from MW-1 indicated slight
higher concentrations of copper than background. The remaining
samples did not indicate any significant concentrations for
metals in the soils.
Using the approximate location of the abandoned pond and
the soil results from the RI, additional soil sampling will be
completed to define the vertical and horizontal extent of
contamination underlying these two impoundments. SDG&E will
complete a minimum of eight additional soil borings in an attempt
to determine the extent of contamination. The approximate
locations of these borings are shown in Figure 4-5-1 while final
locations will be determined at the time of implementation of the
closure plan.
Samples will be obtained at 2 foot intervals starting at
the surface and extending to groundwater for locations where a
drill rig can be used. If the sample location is located on a
side wall of the impoundment, a hand or power auger will be used
and samples will be obtained at 2 foot intervals starting at the
surface and extending to 6 to 10 feet.
METAL-CLEANING WASTEWATER
IMPOUNDMENTS 3 AND 4 \
APPROXIMATE LOCATION OF
FORMER WASTEWATER IMPOUNDMENT
SB1
MW-1
LOW-VOLUME WASTEWATER
IMPOUNDMENTS 1 AND 2
MW-3
PROPOSED SOIL BORING LOCATIONS
EXISTING SOIL BORING LOCATIONS
GROUNDWATER MONITORING WELL LOCATIONS
50 100
GRAPHIC SCALE (FEET)
KM4
11 1J/BB
NONE
FIGURE 4-5-1
PROPOSED LOCATIONS OF
SOIL BORINGS FOR LVW 1 AND :
IMPOUNDMENT CLOSURE PLAN
SDS*E CNC1NA POWER PLAN!
/MITTELH/4USER tcorporahon
SDG&E 4-5-6December 1988'
Encina Power Plant Rev: 0
Closure Plan P1080RM
Sampling Method
Soil samples will be obtained using a backhoe/ hand
auger, or a drilling rig with a hollow stem auger and split-spoon
sampler. Before taking each sample, the sampler will be cleaned
with a non-Phosphate detergent and rinsed with water from a known
source. Boring techniques will ensure that liquid is not
introduced into the boring and will allow accurate detection of
saturated zones. Rinse water and residues from the sampling
procedures will be collected and either treated on-site or
disposed of off-site pursuant to State and Federal Regulations.
Sampling blanks will be taken at the end of each day.
Lithologic logs will be kept for each of the soil
borings. The following parameters will be used to describe the
soils: lithology per Unified Soil Classification System (USCS),
estimated percentages of secondary soil components, soil color per
Munsell color charts, estimated plasticity, estimated consistency
or density, and estimated moisture content. The lithologic logs
will be completed by a qualified geologist or qualified civil
engineer.
After completion of each boring, the hole will be sealed
with bentonite grout to prevent any groundwater contamination
through the boring pathway.
Each soil sample will weigh approximately 1,000 grams.
This will provide an adequate sample for the designated analyses
and replicate analyses, if necessary. Each sample will be placed
in a wide-mouthed glass jar with a Teflon lined lid. Split
samples will be provided to regulatory agencies upon request prior
to sampling.
Soil Analysis
After arriving at the certified laboratory where the
analyses will be performed, the soil samples will be tested for
TPH, pH and total metals to provide levels for use in accordance
with the Closure Step Decision Diagram, Attachment 4-4.
If any contaminated soils are removed, confirmation
samples from the affected quadrant, will be taken and analyzed for
TPH, pH and total metals. The above will be repeated until all
contaminated soils have been removed and the site is clean.
/MITTELH/1USERcorporation
SDG&E 4-5-7 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
G. SAMPLE CONTROL
Each sample container will be labeled with the following
information at the time of sampling:
Facility Name
Sample Number
Sample Location
Sample Type
Date of Sample
Time of Sample
Name of Sampler
Seals will be applied to each container immediately
after collection to prevent tampering with the samples. The seals
will display the following information:
Sample Number
Date of Sample
Two blank samples, a trip blank and a sampling blank,
will be prepared for each day of sampling. The trip blanks will
be deionized water transferred to a sample bottle at the lab. The
sampling blanks will consist of deionized water and will be
handled in a manner similar to the samples. All samples will be
placed in a container and packed in ice as needed. They will then
be sent to the laboratory. The chain of custody procedures that
are described in EPA SW-846 will be followed.
The information pertinent to sampling the asphalt
concrete and soil will be recorded in a hard bound log book.
Entries in the log book will include the following information:
Facility name
Purpose of sampling
Location at sampling site
Field contact
Type of waste sampled
Description of sampling methodology
Date and time of collection
Weather at time of collection
Soil classification, when applicable
Field measurements
Photos, if taken
Signature of personnel responsible for sampling
/MITTELhMUSERcorpora hon
SDG&E
Encina Power Plant
Closure Plan
4-5-8 December 1988
Rev: 0
P1080RM
H. ANALYTICAL PROCEDURES
1. Total Petroleum Hydrocarbon (TPH)- Method 418.1
2. Total Metals - Acid Digestion, Method 3050, SW-846,
Analyze for the following parameters:
Arsenic
Barium
Chromium (total)
Copper
Lead
Mercury
Nickel
Vanadium
Zinc
Method 7060 or 7061
7080 or 7081
7190
210.1 or 220.2
7421
7470 or 7471
7520 or 7521
286.1 or 286.2
289.1 or 289.2
SW-846
SW-846
SW-846
EPA-600/4-79-020
SW-846
SW-846
SW-846
EPA-600/4-79-020
EPA-600/4-79-020
5.
6.
Waste Extraction Test - 22 CAL. Adm. Code 66700. Analyze
the extract for the parameters listed in Item #1 above that
exceed 10 times their STLCs. (Note: EP-toxicity tests will
not be conducted since the WET extract almost always has
higher metal levels due to the use of citrate, a stronger
complexing ligand than acetate.)
Deionized Water Extraction Test - Use WET-procedure, but
with deionized water rather than citric acid for extraction
solution. Analyze extract for above metals listed in
Item #1.
Soil pH - Method 9045, SW-846.
pH - Method 9040, SW-846
Archived samples and extracts for analyses will be held
in storage only for the time and under the conditions specified in
EPA and DHS analytical protocol documents.
/VIITTELHMUSERcorporation
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RM
ATTACHMENT 4-6
LETTER REGARDING
REMEDIAL INVESTIGATION REPORT
STATE OF CALIFORNIA GEORGE DEUKMEJIAN, Governor
CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD
SAN DIEGO REGION
9771 Clainmont Mm Blvd.. Suite 6
S»n Di»go, California 92124-1331
Telephone: 1619) 26&-5114
May 11, 1988
Mr. Fred Jacobsen
San Diego Gas & Electric Company
P.O. Box 1831
San Diego, California 92112
Dear Mr. Jacobsen:
RE: REMEDIAL INVESTIGATION REPORT FOR THE ENCINA POWER PLANT
Regional Board staff has reviewed the ahove referenced document submitted February 22, 1988.
According to the report, soil from beneath the Low Volume Waste (LVW) impoundments contain
vanadium which exceeds the Soluble Threshold Limit Concentration (STLC) standards for
hazardous waste.
The elevated concentrations indicate that a polluted vadose zone exists beneath LVW
impoundment No. 2 which presents a potential threat to water quality. Based on this
information, soil remediation will be necessary beneath the LVW impoundments.
No sample analyses results of the liners or soil from beneath the other impoundments exceed
the Soluble Threshold Limit Concentration (STLC) or the Total Threshold Limit Concentration
(TTLC) standards for hazardous waste and no ground-water sample analyses results exceed
drinking water standards.
San Diego Gas & Electric Company (SDG&E) will be required to continue monitoring the ground
water for possible migration of waste constituents.
It is our understanding, through a meeting with staff on April 6, 1988, that SDG&E has
opted to close the existing surface impoundments due to extensive work needed to meet the
Subchapter 15 seismic criteria for construction. It is our understanding that SDG&E intends
to use above-ground tanks instead of surface impoundments.
SDG&E will be required to close the surface impoundments pursuant to Article 8, Subchapter
i5, Chapter 3, Title 23 of the California Code of Regulations. Under Article 8, SDG&E is
required to submit, for approval, a closure plan detailing closure activities and post-
closure maintenance.
If you have any questions, please call John Anderson at the above number.
Very truly yours,
LADIN H. DELA
Executive Officer
jpa
cc: Charlene Herbst, TPCA Program Manager, Division of Water Quality, Sacramento
/HITTELH>IUSER t.corporation
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RE
SECTION 5.0
SAMPLE CONTROL
/MITTELH/JUSER vcorpora hon
SDG&E 5-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RE
5.0 SAMPLE CONTROL
The closure procedures for the wastewater ponds may
require samples of liquid, sludge, asphalt concrete and soil to be
taken and analyzed. All samples will be labeled and sealed to
prevent contamination of, or tampering with, the samples. Any
shipping container will also be sealed.
To establish the documentation necessary to trace sample
possession from the time of custody, a Chain of Custody Record
will be filled out and will accompany every set of samples.
The laboratory will conduct established quality control
procedures throughout the analyses. This will include blanks,
spikes, internal standards, and duplicate samples. SDG&E will
split some of the samples and label them differently and use them
as a quality control procedure. This information will be available
for each sample set.
Further details are presented in the Sampling and
Analysis Program in Attachment 4-5.
/VIITTELH/1USER t.corporation
SDG&E December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RF
SECTION 6.0
DECONTAMINATION OF FACILITY EQUIPMENT
/V1ITTELH>1USER u^corporation
SDG&E 6-1 December 1988
Encina Power Plant Rev: 0
Closure Plan P1080RF
6.0 DECONTAMINATION OF FACILITY EQUIPMENT
All wastes will be removed from the ponds and either
discharged in compliance with SDG&E's NPDES permit or be shipped
to an approved disposal site by a registered waste hauler. When
closure is complete, all equipment and structures associated with
the ponds which will not be used with the new abovegrade tank
treatment system will have been properly disposed of or
decontaminated by removing wastes and residues.
Pipelines, valves, pumps and fittings which convey waste
to the ponds will be flushed. Flush water will be collected in
temporary tanks such as a Baker Tank or in the ponds and be
treated in the on-site wastewater treatment system or disposed of
off-site pursuant to State and Federal Regulations. Wastewaters
treated on-site will be discharged pursuant to the Plant's NPDES
Permit.
Equipment used during closure for sampling or to clean
the asphalt concrete will also be decontaminated. Cleaning of
this equipment during the closure activities will be done in a
portable tank or in a bermed area such as a "Porta-Berm" system.
The wash water will be disposed in the same manner as the flush
water from the pipeline decontamination activity.