LBWD’s Prototype-Scale Testing of NF LBWD’s Prototype-Scale Testing of NF Membranes for Seawater DesalinationMembranes for Seawater Desalination

Robert C. Cheng, Tai J. Tseng, Kevin L. WattierRobert C. Cheng, Tai J. Tseng, Kevin L. Wattier

February 17, 2011February 17, 2011

MSSC National Salinity SummitMSSC National Salinity Summit

11

Research Partners

US Bureau of Reclamation CA Dept. of Water Resources LA Department of Water and

Power Southern Nevada Water

Authority Tampa Bay Water Authority

UCLA University of New

Hampshire Clemson University University of Illinois Montana State University University of Central

Florida Virginia Tech University of Nevada, Reno University of Iowa

AcademiaGovernment

Industry DuPont Water Research Foundation

(AwwaRF) Black & Veatch CH2M Hill MWH

Water resources…under stress Los Angeles Aqueduct: reduction

California Aqueduct:“Southern California Loses Up to 30 Percent of Its Supplies from Delta Next Year and Possibly Longer”-Business Wire News

Colorado River Aqueduct: ~50% reduction

…more pressure to act

locally to reduce

dependence on importsCity of Long Beach

~500,000 residents

Reliability, at lowest reasonable rates

“New”

Conjunctive Use

Seawater

Consumers

Potable

“Traditional”

Groundwater

Surface water

Conservation

2007 Declaration

16+% decrease in use

“100 by 100” Initiative

Seawater barrier

Irrigation

Indirect recharge

Reclaimed

LBWD’s Resource MixLBWD’s Resource Mix

20102010 20152015

Conservation 15%

Reclaimed 9%

Imports32%

Groundwater 44%

Conservation 15%

Reclaimed12%

Imports 30%

Groundwater 33%

Desal 10%

55

Shifts in water resources

47%

20072007(declaration of drought)(declaration of drought)

20102010(shortage allocation)(shortage allocation)

53%53%

ImportsImports (MWD)(MWD)

Groundwater(LBWD)

$478 - $574/af$478 - $574/af

Groundwater

53%

< $400/af$300/af

47%47%

ImportsImports

$740 - $740 -

$3,134$3,134/af/af

Desal research...to lessen risksDesal research...to lessen risks

Full plant cost will be costlyFull plant cost will be costly Other full-scale experiences point out Other full-scale experiences point out

value for researchvalue for research Substantial interest for accurate Substantial interest for accurate

operational and cost informationoperational and cost information Federal – USBR (federal authorization)Federal – USBR (federal authorization) State – CA DWR (CA Prop 50 funding)State – CA DWR (CA Prop 50 funding) Local – LA DWP (research site, power)Local – LA DWP (research site, power)

O&M- Electrical Power44%

Debt (Capital)37%

Membrane Replacement

5%Labor

4%

Maintenance & Parts

7%

Consumables3%

Federal Roadmap EstimatePower + Debt = 81%

Non-energy O&M = 19%Non-energy O&M = 19%

Concept - Concept - ““The Long Beach The Long Beach

Method”Method”Two PassTwo Pass

NanofiltrationNanofiltration

Energy Savings Lower pressure requirements,

lower energy consumption

Quality Protection Twice the protection of

single-pass technology

NF membrane for seawater desalNF membrane for seawater desal

Proof-of-conceptProof-of-concept Initiated testing ~2001Initiated testing ~2001 verified through 2-yr AwwaRF project, verified through 2-yr AwwaRF project, “A “A

Novel Approach to Seawater Desalination Novel Approach to Seawater Desalination Using Dual-Staged Nanofiltration”Using Dual-Staged Nanofiltration”

Patent applicationPatent application US patent 7144511, granted 12/5/06US patent 7144511, granted 12/5/06 ““Two stage nanofiltration desalination Two stage nanofiltration desalination

system”system” Prototype plant construction/operationsPrototype plant construction/operations

2004 - 20102004 - 2010

1111

How to integrate seawater into How to integrate seawater into system?system?

Post treatment / DistributionPretreatment NF2 or RO

A $20 M, 10-year investment A $20 M, 10-year investment Leverage various partnerships for technical input and other Leverage various partnerships for technical input and other

supportsupport Federal/State/Local Funds, 50% funding by ReclamationFederal/State/Local Funds, 50% funding by Reclamation

•Under Ocean Floor Intake and Discharge

•Prototype•UV/ClO2

•Mitigation of WQ impacts due to integration of new source

Jul

07 -

Jan

04

-

Jul

04 -

Jan

05

-

Jul

05 -

Jan

06

-

Jul

06 -

Jan

07

-

Jan

08

-

ConstructionConstruction

Jan

09

-

Jul

08 -

Jan

10

-

Jul

09 -

Jul

10 -

DesignDesign

Desal Prototype Research

ClO2 and UV

Under Ocean Floor

Desal Site Alternative Study

SiteRestoration

Restoration(2012)

Post-treatmentDesignDesign

DesignDesign

Research schedule

Jan

11

-

SouthTrain

North Train

MF Unit

Prototype Plant Flow DiagramPrototype Plant Flow Diagram

1313

Intake/discharge

Intake/discharge

Projectsite

Projectsite

Prototype PlantPrototype Plant 300,000 gpd facility, 8-in vessels300,000 gpd facility, 8-in vessels

1414

Energy Recovery OperationEnergy Recovery Operation

PX Booster pump

PX

1515

Other IssuesOther Issues

TechnicalTechnical Water quality met (boron, bromide, etc.)Water quality met (boron, bromide, etc.) Blending issues with existing waterBlending issues with existing water

EnvironmentalEnvironmental Impingement/entrainmentImpingement/entrainment DischargeDischarge

Public TrustPublic Trust Sound investmentSound investment TransparencyTransparency

PermittingPermitting

Research ObjectivesResearch Objectives Compare NFCompare NF22 against RO against RO

Water quality (TDS, boron, bromide), energy, Water quality (TDS, boron, bromide), energy, reliabilityreliability

Optimize NFOptimize NF22 process process Energy recovery deviceEnergy recovery device Biofouling control method: UV vs. ClOBiofouling control method: UV vs. ClO22

Vary configuration/membranesVary configuration/membranes

Analyze cost for full-scale plantAnalyze cost for full-scale plant

1717

Research ApproachResearch Approach

Phase I- NFPhase I- NF22 vs. RO vs. RO Short tests to determine trendsShort tests to determine trends General WQ and energy recovery monitoringGeneral WQ and energy recovery monitoring May ’06 – Dec ‘07May ’06 – Dec ‘07

Phase II-NFPhase II-NF22 vs. RO vs. RO 2+ weeks of selected conditions from Phase I2+ weeks of selected conditions from Phase I Detailed WQ analysesDetailed WQ analyses Jan ’08 – Dec ‘08Jan ’08 – Dec ‘08

Phase III and IV-NFPhase III and IV-NF22 optimization test optimization test 2+ weeks tests: NF 5 vs. 7, mixed membrane 2+ weeks tests: NF 5 vs. 7, mixed membrane UV vs. ClOUV vs. ClO22

Jan ’09 – Jan ‘10Jan ’09 – Jan ‘10

1818

NFNF22 vs. RO Process vs. RO Process

Membranes Pressure (psi) Recovery (%)

NF2 Pass 1 NF90 540 39%

NF2 Pass 2 NE90 184 72%

RO Pass 1 SWC3+ 756 40%

RO Pass 2 NE90 218 80% 1919

MF

Energy Recovery

1st Pass NF(South Train)

Cartridge Filter

Combined Effluent Tanks

Cartridge Filter

Backwash water

Influent Tank

Energy Recovery

2nd Pass NF(South Train)

2nd Pass NF(North Train)1st Pass RO or NF

(North Train)

Water Quality GoalWater Quality Goal

Total dissolved solids (TDS)Total dissolved solids (TDS) TDS <500 mg/L-secondary WQ standardTDS <500 mg/L-secondary WQ standard

Bromide - accelerate disinfectant decayBromide - accelerate disinfectant decay Bromide <0.4-0.5 mg/L to maintain residualBromide <0.4-0.5 mg/L to maintain residual

Boron - toxic to plants at high levelBoron - toxic to plants at high level California notification level = 1 mg/LCalifornia notification level = 1 mg/L

No “backsliding” of water quality from new No “backsliding” of water quality from new sourcesource

2020

Selecting appropriate base addition location is critical

Base Addition StrategyBase Addition Strategy

Base Injection PtOption 1

Base Injection PtOption 2

• More base required to alter pH

• HIGH potential for fouling

Alk = 122 mg/L

Ca2+ = 447 mg/LAlk = 10.4 mg/L

Ca2+ = 11.7 mg/L

• Less base required to alter pH

• 97% rejection of Ca2+. Decreased potential for fouling

Pass 1 Pass 2

NFNF22 vs. RO, Boron vs. RO, Boron

2222

0

1

2

3

4

5

6

7.4 gfd -34% 5.6 gfd -27% 8.5 gfd-37% 8.5 gfd -37%

Bo

ron

(mg

/L)

Flux-recovery

Raw Pass 1 (RO) Pass 2 (RO/NF )

CaNL

Specific Energy SummarySpecific Energy SummaryPermeate B <0.8 mg/LPermeate B <0.8 mg/L

10.1

11.2

11.6

9.3

8.2

9.7

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

NF2 SWRO (2 pass)

Sp

ecif

ic E

ner

gy

(kW

h/k

gal

)

Maximum

Minimum

50% value

75% value

25% value

50th percentile specific savings = 20%

NFNF22 vs. RO vs. RO

Two-pass RO required to meet all water quality objectives Boron < 1 mg/L Consistent with USBR DWPR Report 127

NF2 required less specific energy than RO/NF NF2 required 20% less energy (50th percentile)

Mixing Membranes in NFMixing Membranes in NF22

Pass 1 - two stage configurationStage 1 holds 5 elements/vessel

2525

ULP ROULP RO

Improve flux and water quality by changing membrane types within a vessel

NFNF22 Optimization Test Optimization Test

2626

Configuration Pressure FluxProd. TDS

kWh/1000 gal

Last elem flow

Last element pressure

Ranking

NF-NF-NF-NF-NF 573.9 7 4366 13.86 13 539.9  NF-NF-NF-NF-ULP 593 7 3699 14.32 13.2 536  ULP-NF-NF-NF-NF 588.9 7 3843 14.22 12 539.9 2

ULP-ULP-NF-NF-NF 604 7 3284 14.58 13.3 538 1NF-NF-NF-ULP-ULP 612.7 7 2987 14.79 14.4 499.6 3

ULP-ULP-ULP-NF-NF 623 7 2857 15.04 13.5 535.2  NF-NF-ULP-ULP-ULP 642.5 7 2336 15.51 12.6 565.5  

BW-NF-NF-NF-NF 597 7 3882 14.42 12 534.4  BW-BW-NF-NF-NF 627.7 7 3200 15.15 13.5 522.8  BW-BW-BW-NF-NF 667.5 7 2512 16.13 11.9 518.2  

Source: Trussell, R.S., Sharma, R.R., Trussell, R.R. 2009. Optimization modeling of nanofiltration membranes for seawater desalination: Scale-up from pilot to prototype scale. In AWWA Membrane Technology Conference (Memphis, TN).

NFNF22 Optimization Test – Energy Optimization Test – Energy

2727

0

2

4

6

8

10

12

NF 5 NF 7 2 ULP + 5 NF 90

1 ULP + 6 NF90

5 NF90 + 2 ULP

1 ULP + 4 NF90

2 ULP + 3 NF90

1 ULP + 6 NF90

NF 7 NE 7

7.2 gfd-39%

6.8 gfd-34%

5.5 gfd-33%

5.3 gfd-33%

5.2 gfd-33%

7.7 gfd-38%

7.1 gfd-35%

6.5 gfd-34%

5.0 gfd-29%

5.1gfd-30%

South North South South South North North South North North

n=793 n=2320 n=2561 n=3662 n=6417 n=2308 n=2185 n=7367 n=15034 n=1241

En

erg

y (k

wh

r/k

ga

l) No UV/ClO2

UV ClO2

NFNF22 Optimization Summary Optimization Summary

No clear difference in energy consumption No clear difference in energy consumption between 5 & 7 elements in seriesbetween 5 & 7 elements in series

More ULP membranes in lead position reduced More ULP membranes in lead position reduced energy consumptionenergy consumption

2828

Cost AnalysisCost Analysis

Cost curvesCost curves Based on historical information Based on historical information

Cost modelsCost models Use location-specific parameters Use location-specific parameters

NFNF22 cost model cost model Based on ADC cost model (funded by Based on ADC cost model (funded by

Reclamation)Reclamation) Modified by LBWD, used Prototype dataModified by LBWD, used Prototype data

2929

NFNF2 2 Cost Model ScenariosCost Model Scenarios Scenarios testedScenarios tested

Highest overall system recoveryHighest overall system recovery Lowest specific energy (kWh/kgal)Lowest specific energy (kWh/kgal) Highest flux (gfd)Highest flux (gfd)

Different production rateDifferent production rate 50 mgd50 mgd 5 mgd5 mgd

3030

Variables analyzedVariables analyzed

Variable Baseline Variable EffectProject life 30 yrs 25 yrs Capital

Interest rate 5% 4%, 6% CapitalMembrane

life6.5 yrs 10 yrs Non-energy O&M

Energy cost $0.12/kWh $0.15/kWh Energy O&M

Cost AnalysisCost Analysis

Two pass RO NF NF2

Scenario 1 Scenario 2 Scenario 1 Scenario 2 Scenario 3

Pass 1

Pass 2 Pass 1

Pass 2

Pass 1

Pass 2

Pass 1

Pass 2

Pass 1

Pass 2

Flux (gfd) 6.91 15.89 5.41 11.47 6.65 19.55 6.29 15.35 7.05 15.17

Recovery (%) 42% 82% 35% 75% 46% 75% 45% 78% 44% 80%

Overall recovery (%) 34% 27% 38% 41% 39%

Energy (kWh/kgal) 9.3 1.7 9.8 1.3 6.6 1.6 7.0 2.2 7.4 2.3

Optimization parameter

Capital, energy   Energy  Capital  Capital

3232

50 mgd vs. 5 mgd Energy O&M independent of size Capital and Non-Energy O&M

Capacity dependent items• Membrane replacements, solid disposal, maintenance, labor• Chemical cost

Capital reduction factors varied for 50 mgd vs 5 mgd• 20% – process piping, solid disposal, etc.• 32% - pumps, chemical systems, etc.• 44% – yard piping, site work, etc.

Capacity independent item • Permitting - $10M (15% of overall capital cost for 5 mgd, 3%

of overall capital cost for 50 mgd)

Cost AnalysisCost Analysis

3434

Baseline5 MGD - 30 Years, $0.12/kWh, 5% interest, 6.5 yrs membrane life

1.5

5

1.6

1

2.3

5

2.5

3

2.3

3

2.3

4

2.3

2

2.9

6 3.2

2

2.9

2 3.6

4

2.9

2

1.7

8

1.9

0

1.4

4

7.107.66

6.69

7.536.85

0

1

2

3

4

5

6

7

8

9

10

RONF 1 - 6.91gfd/31%

RONF 2 - 5.41gfd/27%

NFNF 1-6.65gfd/38%

NFNF 2-6.29gfd/41%

NFNF 3-7.05gfd/39%

Cos

t ($/

kgal

)

Energy O&M Component Non-Energy O&M ComponentCapital Cost

Double Pass NF NFDouble Pass RO NF

InflationInflation

Produced water cost can more than double Produced water cost can more than double over project lifeover project life Historical increase of 3% for goods (Historical increase of 3% for goods (www.bls.gov

)) Energy increased by 4%Energy increased by 4%

• Inflation projection for energy from historical dataInflation projection for energy from historical data

3535

Cost AnalysisCost Analysis

Project life = 30 yearsProject life = 30 years 50 mgd 50 mgd

• RO-NF ~ $3.6 BRO-NF ~ $3.6 B

• NFNF22 ~ $3.2 B ~ $3.2 B

5 mgd 5 mgd • RO-NF ~ $0.58 B RO-NF ~ $0.58 B

• NFNF22 ~ $0.57 B ~ $0.57 B

3636

CostsCosts

ADC model usedADC model used Inputs modified to include research findings

Size of facility has significant impactsSize of facility has significant impacts Scaling down from 50 mgd to 5 mgd can increase

cost up to 100%

Sensitivity analysisSensitivity analysis Membrane life, power, interest rate, project life Most sensitive to interest rate and power

Cost of desalinated water (2010)Cost of desalinated water (2010) $1,350/AF for NF2, $1,640/AF for RO/NF (50 mgd) $2,454/AF for NF2, $2,496/AF for RO/NF (5 mgd)

Next stepsNext steps

??

Report for USBR in printReport for USBR in print

Research Presentations

www.lbwater.orgwww.lbwater.org

Questions?