HomeMy WebLinkAbout1998-07-07; Municipal Water District; 417; Capacitive Deionization Water Purification System- I Qlr-,K
CARLSBAD MUNICIPAL WATER DISTRICT -AGENDA BILL
AB# % TITLE: DEPT. HD. &@-
MTG. 07/07/98 CAPACITIVE DEIONIZATION WATER
PURIFICATION SYSTEM TESTING AND CITY ATTY. ?I+
DEPT. CMWD EVALUATION PROJECT
RECOMMENDED ACTION:
This item is a report on the current developments concerning the Capacitive Deionization
Water Purification System Testing and Evaluation Project, and no Board action is being
requested.
ITEM EXPLANATION:
Capacitive Deionization (CDI) is a process that can be used to desalinate brackish water and
seawater. More recently, Lawrence Livermore National Laboratory (LLNL) developed
carbon aerogel electrodes and incorporated these into the CDI process. The carbon aerogel
dramatically improved the effectiveness of CDI in removing salts.
The District has been investigating the CDI process. A part of the City Council goal to
develop a seawater/groundwater desalination program. The District is interested in obtaining
sufficient background information to enable the development of a pilot plant. In January,
1998, the District received a proposal from Terra Research Division of Farwest Group, Inc.
(Farwest) to test a 100 gallon per day CDI with carbon aerogel electrodes. Far-west obtained
a license to develop and utilize the CDI technology from LLNL. Farwest is providing this CDI
system at no cost to the District. Their primary goal is to demonstrate that a CDI system can
operate in the “Real World” environment of a municipal utility.
Farwest will be delivering their CDI system sometime during the second or third week of July,
1998. The CDI system will be self-contained within a trailer, and it will be located at the
Encina Water Pollution Control Facility. The site area will be approximately 8-feet by 12-feet
located adjacent to the secondary clarifiers. The electrical system requires only a 110 volt
power supply. Groundwater will be supplied to the CDI system from existing wells at the
treatment plant.
The equipment from Fat-west will be automated, simple to operate and complete with
measuring devices. Farwest will have a technician onsite for three weeks to ensure
satisfactory operation of the CDI equipment. After that time period, the District will conduct a
test program to evaluate the CDI system. The test program will primarily consist of flow
measurements, conductivity measurements, and power consumption measurements. It is
very important to collect the data necessary for calculating the amount of desalted water
produced per unit of energy consumed (e.g. watt-hours per gallon) and per unit of aerogel
surface area (i.e. gallons per day per square foot of electrode area). Raw data needed to
calculate the above parameters are listed on Exhibit 2.
Although the CDI equipment is provided at no cost to the District, there are costs to conduct
the tests. These costs include the following:
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Page 2 of Agenda Bill ho. Y/ 7
Item Description Budget
1. District staff time to collect the data and write a summary report. $11,000
2. Carollo Engineers will be used to assist the District in
developing the test procedures, reporting forms, reviewing
reports, and making observations in the field. $ 8,860
3. LLNL is willing to conduct experiments to investigate
regeneration, fouling, and energy efficiency. At the end of the
test program, a report would be prepared jointly with the District
and a publication of the results would be expected. $24,000
4. Encina laboratory would be used to measure the actual TDS
levels in the source water and desalinated water. This is
expected to be once a week. Nominal
Total time period for the test program is approximately three months.
FISCAL IMPACT:
The District will utilize funding for this demonstration project from the appropriation approved
under Resolution No. 959 on October 22, 1996. This appropriation is contained in the
1998/99 fiscal year, Capital Improvement Program. The District has received funds from the
San Diego County Water Authority in the amount of $32,940.
ENVIRONMENTAL IMPACT:
The demonstration project is exempt from the environmental review process in accordance
with CEQA Article 10 Categorical Exemptions Class 6.
EXHIBITS:
1. Location Map
2. READING/DATA COLLECTION.
3. Resolution No. 959.
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READING/DATA COLLECTION
EXHIBIT 2
l Operating Time per Day
- Operating time of each production cycle
- Operating time of each “flush” cycle (polarity reversal)
l Feedwater Flow - Instantaneous flow (gals/hour, liters/hour, or milliliters/hour, etc.)
- Total flow per day (gallons or liters per day)
- Total flow for each production cycle (gallons or liters per cycle)
l Product Water Flow
- Instantaneous flow (gals/hour, liters/hour, or milliliters/hour, etc.)
- Total flow per day (gallons or liters per day)
- Total flow for each production cycle (gallons or liters per cycle)
- Total flow for each “flush” cycle (gallons or liters per cycle)
l Conductivity of Feedwater (microsiemens/centimeter)
- Since this probably will not change, periodic readings, say once or twice per hour should be
sufficient.
l Conductivity of Product Water (ms/cm)
- This will be recorded continuously.
l Power Consumption (watt-hours)
- For each production cycle
l Flush Cycle Flow and Duration (also see “Product Water Flow” above)
- Measure and record the flow in gallons or liters per cycle.
- Measure and record flush cycle/polarity reversal time in minutes and/or seconds.
Note: It is important to obtain these data as accurately as possible as this gives the amount (and
percentage) of “brine” from the aerogel desalting process.
l Flush Cycle “Brine” Conductivity
- Measure and record the conductivity of the flush cycle “brine” in microsiemens/centimeter.
This data may be used in an attempt to calculate a material balance of the salts (dissolved ions)
going “in” and “out” of the carbon-aerogel unit.
- If possible, frequent readings may be taken to see how the conductivity of the flush water changes over the time period of the flush cycle.
l Temperature Reading (OF or o C)
- Temperature of the process water (feed or product) should be measured and recorded once or
twice per hour.
Note: The operating temperature is not expected to change very much; so it will not be
necessary to take frequent temperature readings.
l pH Readings
- It is not expected that the pH of the process water will change very much. However, it is
recommended that pH readings be taken once or twice per hour; and/or once or twice per
operational cycle.
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RESOLUTION NO. 959 EXHIBIT 3
I A RESOLUTION OF THE BOARD OF DIRECTORS OF THE
CARLSBAD MUNICIPAL WATER DISTRICT, CARLSBAD, CALIFORNIA, FOR APPROVAL AND AUTHORIZATION OF THE
CAPACITIVE DEIONIZATION DEMONSTRATION PROJECT
WITH LAWRENCE LIVERMORE NATIONAL LABORATORY,
CMWD PROJECT NO. 96-101 ,
WHEREAS, the Lawrence Llvennore National Laboratory (LLhL) has constructed a
7 2,000 gpd pilot plant, and LLNL has indicated their concurrence to locate the pilot plant for a
8 period of up to four weeks in Cartsbad; and
9 WHEREAS, the Capacitive Deionization Pilot Plant can be located at the Encina Water
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Pollution Control Facility for the purpose of demonstrating its treatment capability on local
~ groundwater through the use of existing wells; and
WHEREAS, the Board of Directors of the Carfsbad Municipal Water Dist$ct of
Cansbad, California has determined that the Capacitive Deionization Demonstration Project
with Lawrence Livermore National Laboratory would provide valuable information with regard
to the capability of the capacitive deionization process to be used in treating local brackish
l7 groundwater and seawater, an alternative water supply, for Catlsbad; and
18 WHEREAS, the Capacitive Deionization Demonstration Project would be in concert
19 with the City Council Goal of investigating desalination technologies; and
20 WHEREAS, the budget for the Capacitive Deionization Demonstration Project has
21 been estimated at $66,000, and approximately $16,000 has already been appropriated in the
22 Water District’s 1996-97 operating budget; and - 23
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WHEREAS, the San Diego County Water Authority has agreed to reimburse the Distnct
for one-half the cost of the demonstration project, up to $32,940, with the stipulation that the
25 funds would be repaid if a full scale treatment facility was developed in the future as a result of 26
27 this demonstration projed; and
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WHEREAS, the Olivenhain Municipal Water District has pledged $5,000 toward the
cost of the project
NOW, THEREFORE, BE IT RESOLVED, by the Board of Directors of the Cansbad
Municipal Water District of Carlsbad, California as follows:
1. That the above recitations are true and conect. *
2. That the funds in the amount of $ 49,860 for the Capacitive Deionization
Demonstration Project will be appropriated from the Water Capital Replacement Fund.
PASSED, APPROVED AND ADOPTED at a special meeting of the Carl&ad Municipal
Water District held on the 22nd day of OCTOBER , 1990, by the following
vote to wit:
AYES: Board Members Lewis, Nygaard, Kulchln, Finnila, Hall
NOES: None
ABSENT: None
ATTEST:
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CMWD 96-101
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