Desalination for Marin CountyDesalination for Marin County

Paul HellikerGeneral Manager

Marin Municipal Water District

North Bay Watershed Association

April 5, 2007

Paul HellikerGeneral Manager

Marin Municipal Water District

North Bay Watershed Association

April 5, 2007

2-Minute History of MMWD Water2-Minute History of MMWD WaterAnnual Rainfall: 1879 through 2001

1912

MMWD formed

1948

Bon Tempe

1953

Kent

1960

Nicasio

1976

First Russian River Imports

1918

Alpine

1971

Measure B Fails

1977

Richmond Bridge Pipeline

1979

Soulajule

1982

Kent Lake Raised

1990

Pilot De-Sal Plant

1991

Measure W Fails

1992

Measure V Passes

1996

Lagunitas Creek

Settlement

Reservoirs72%

Russian River (via NMWD )

26%

Recycled2%

Current MMWD SuppliesCurrent MMWD Supplies

Supply will decrease 25%

Climate uncertainties

Highcost

Projected Supply and DemandProjected Supply and Demand

Current Yield

Future Yield

Acre-feet1987 Demand

0

5000

10000

15000

20000

25000

30000

35000

2002 2005 2010 2015 2020

Projected 2020 ScenarioProjected 2020 Scenario

Current supply deficit: 3,200AF Demand increase: 1,560AF Projected loss of NMWD

capacity: 2,300AF Total projected deficit: 7,060 AF

Current supply deficit: 3,200AF Demand increase: 1,560AF Projected loss of NMWD

capacity: 2,300AF Total projected deficit: 7,060 AF

MMWD OptionsMMWD Options Conservation

– Remains first choice– Already achieved 25% savings– BMPs implemented and very aggressive tiered rates– Additional reductions may cost more than other options

Recycling– Currently have many innovations in place– Expansion complicated by cost and water quality issues

Imports– Endangered species protection limitations– Least costly now – likely increase

Desalination– Reliable supply– Cost and energy use are major issues

Conservation– Remains first choice– Already achieved 25% savings– BMPs implemented and very aggressive tiered rates– Additional reductions may cost more than other options

Recycling– Currently have many innovations in place– Expansion complicated by cost and water quality issues

Imports– Endangered species protection limitations– Least costly now – likely increase

Desalination– Reliable supply– Cost and energy use are major issues

MMWD PlanMMWD Plan– Proximity to

infrastructure– Mix brine with

wastewater in existing deep water outfall

– Intake water is less saline and is warmer than ocean

– No power plant impacts

– Public ownership– Reduce imports

MMWD Desalination Pilot Program & EIR

MMWD Desalination Pilot Program & EIR

- Nine/Twelve month demonstration and test

- Conventional/MF/UF pretreatment, 4 Reverse Osmosis makes

- Chemical, biological testing of water streams

- Dilution modeling- Fisheries studies- Entrainment analysis

- Nine/Twelve month demonstration and test

- Conventional/MF/UF pretreatment, 4 Reverse Osmosis makes

- Chemical, biological testing of water streams

- Dilution modeling- Fisheries studies- Entrainment analysis

Intake ScreeningIntake Screening

Designed to meet Federal and State criteria for fish protection– 3/32-inch openings– <0.3 fps velocity– airburst cleaning

Located at end of existing 2000-ft pier

Multiple screens for full-scale facility

Designed to meet Federal and State criteria for fish protection– 3/32-inch openings– <0.3 fps velocity– airburst cleaning

Located at end of existing 2000-ft pier

Multiple screens for full-scale facility

Reverse Osmosis (RO) Desalination

Reverse Osmosis (RO) Desalination

Tested four manufacturers

Three RO elements per train

Initial problems with non-standard sizes

All performed acceptably – fewer cleanings with MF/UF

Tested four manufacturers

Three RO elements per train

Initial problems with non-standard sizes

All performed acceptably – fewer cleanings with MF/UF

Bay Fish SamplingSummary of Results

Bay Fish SamplingSummary of Results

Northern anchovy & Pacific herring common in midwater trawl

Bay goby, shiner perch common in otter trawl

Dungeness crab most common invertebrate

Species composition similar to CDFG sampling

Spiny dogfish not collected by CDFG

Long-term CDFG data can be used in the environmental analysis

Northern anchovy & Pacific herring common in midwater trawl

Bay goby, shiner perch common in otter trawl

Dungeness crab most common invertebrate

Species composition similar to CDFG sampling

Spiny dogfish not collected by CDFG

Long-term CDFG data can be used in the environmental analysis

E n v iron m en ta l

Measurement of species composition, seasonal distribution, and densities of icthyoplankton, crab, shrimp, oysters

Twice monthly for 12 months Use Empirical Transport Model,

Adult Equivalent Loss and Fecundity Hindcast models to estimate entrainment impacts

Measurement of species composition, seasonal distribution, and densities of icthyoplankton, crab, shrimp, oysters

Twice monthly for 12 months Use Empirical Transport Model,

Adult Equivalent Loss and Fecundity Hindcast models to estimate entrainment impacts

Pilot Plant Entrainment StudyPilot Plant Entrainment Study

0.000224*200565,866yellowfin goby

N/A4540615,864northernanchovy

0.0002983,0894,6981,860,969unidentifiedgobies

0.00062567,45831,396229,061,594Pacific Herring

ETM:Pm Estimate

Annual AELEstimate

Annual 2FHEstimate

Total AnnualEntrainment

Taxa

Estimated EntrainmentEstimated Entrainment

Results to DateResults to Date

ETM estimates range from 0.02 – 0.06%, well below sustainable harvest level of 30-40%

No northern anchovies in source water – no ETM estimate

No salmon, steelhead or sturgeon larvae were collected

ETM estimates range from 0.02 – 0.06%, well below sustainable harvest level of 30-40%

No northern anchovies in source water – no ETM estimate

No salmon, steelhead or sturgeon larvae were collected

Brine Discharge AnalysisBrine Discharge Analysis

Analyzed near- and far-field dilution of brine in sewage effluent

Brine flows stable, up to 15 MGD Sewage highly variable flow: 2 – 100 MGD Near field dilutions average 200:1, min. of

9:1 Far field dilutions in San Rafael Bay of

1500:1

Analyzed near- and far-field dilution of brine in sewage effluent

Brine flows stable, up to 15 MGD Sewage highly variable flow: 2 – 100 MGD Near field dilutions average 200:1, min. of

9:1 Far field dilutions in San Rafael Bay of

1500:1

Size of the Initial Mixing ZoneSize of the Initial Mixing Zone

Worst Case: 650m x 250m

Mean: 30m x 15m

Brine Mixture BioassaysBrine Mixture Bioassays Acute bioassays on mysid

shrimp, topsmelt, marine algae at 79%, 27% and 5% brine– No significant impacts

Chronic bioassays on giant kelp, bay mussel, inland silverside at 79% and 27% brine– No significant impacts under

EPA protocol (correct salinity)– Sublethal impacts for high-

brine mix– No major differences from

sewage effluent alone

Acute bioassays on mysid shrimp, topsmelt, marine algae at 79%, 27% and 5% brine– No significant impacts

Chronic bioassays on giant kelp, bay mussel, inland silverside at 79% and 27% brine– No significant impacts under

EPA protocol (correct salinity)– Sublethal impacts for high-

brine mix– No major differences from

sewage effluent alone

Water Supply AnalysisWater Supply Analysis

Testing for:– 100 Regulated compounds or compounds that require

monitoring – 250 non-regulated compounds – An additional 100 non-regulated compounds specific

to SF Bay (incl. flame retardants, algal toxins)– E-screen bioassay

6,000 Data Points to Evaluate Water Quality and Treatment Performance

Testing for:– 100 Regulated compounds or compounds that require

monitoring – 250 non-regulated compounds – An additional 100 non-regulated compounds specific

to SF Bay (incl. flame retardants, algal toxins)– E-screen bioassay

6,000 Data Points to Evaluate Water Quality and Treatment Performance

Desalinated Water Quality ResultsDesalinated Water Quality Results

ConstituentsMaximum

Contaminant Level (MCL)a

SF Bay Watera Desalinated Watera

Existing MMWD

Sourcesa

Sodium N/A 7,100 21 18 – 20

Chloride 250b 12,000 20 8 – 21

Total Organic Carbon (TOC)

2c 0.86 ND 1 – 2

Boron 1d 2.3 0.2 ND – 0.28

Ethylene Dibromide

0.00005 0.00002e ND ND

Mercury 0.002 ND 0.0003e ND

a - ppmb – Federal Secondary (aesthetic) Standardc – based on MMWD source water qualityd – CA DHS notification levele – 4 of 5 samples tested non-detect

Detailed List of Constituent Sample Results Available

Energy for Desalting Seawater is Similar to Common Appliances

Energy for Desalting Seawater is Similar to Common Appliances

At 7.15 kWh/1000 gal seawater desalination requires only 1.9 kWhr/day of power to produce 270 gallons per day.

81 Watts

1.9 kWh/day

2.4 kWh/day

140 Watts

3.4 kWh/day

75 Watts

1.8 kWh/day

100 Watts

2.4 kWh/day

100 Watts avg.

On average, MMWD households use 270 gallons of water per day

Desal would be approx. 0.7% to 3% of Annual Marin Energy UseDesal would be approx. 0.7% to 3% of Annual Marin Energy Use

0200400

600800

10001200

140016001800

Current MMWDEnergy Use

Desal (AvgConditions)

Desal(Drought

Conditions)

Marin CountyEnergy Use *A

nn

ua

l En

erg

y U

se

, Mill

ion

kW

hr

pe

r y

ea

r

* From California Energy Commission for year 2000

Desal Energy is like an extra lightbulb in every Marin homeDesal Energy is like an extra

lightbulb in every Marin home

Average operation would be like an extra compact fluorescent bulb on all the time

Drought operation would be like a standard 100-W bulb on all the time

MMWD will be considering renewable power to supply this energy need

Average operation would be like an extra compact fluorescent bulb on all the time

Drought operation would be like a standard 100-W bulb on all the time

MMWD will be considering renewable power to supply this energy need

• Desalination facility: $81-121 million• Non-construction costs (permitting, construction

management, etc.): $7-10 million• In-system distribution improvements (Phases IV

and V): $22 - 42 million

Total $110 - 173 million

Annual operating costs: $4 – 12 millionNormalized cost: $2,433 - $2,023 per acre-foot

• Desalination facility: $81-121 million• Non-construction costs (permitting, construction

management, etc.): $7-10 million• In-system distribution improvements (Phases IV

and V): $22 - 42 million

Total $110 - 173 million

Annual operating costs: $4 – 12 millionNormalized cost: $2,433 - $2,023 per acre-foot

Cost of Desalination OptionCost of Desalination Option