mprwa evaluation of seawater desalination projects final report december 2012

7/30/2019 MPRWA Evaluation of Seawater Desalination Projects Final Report December 2012

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Evaluation of Seawater Desalination Projects

Final Report

December 2012

prepared for:

Monterey Peninsula Regional Water Authority

by:

Separation Processes, Inc.

and

Kris Helm Consulting


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY TABLE OF CONTENTS

CONTENTS

EXECUTIVESUMMARY.......................................................................................................................................1

PROJECTSUMMARIES...............................................................................................................................................1

PROJECTFUNCTION..................................................................................................................................................

2

PROJECTPERFORMANCE..........................................................................................................................................4

ECONOMICS..............................................................................................................................................................5

IMPLEMENTATIONCONSIDERATIONS......................................................................................................................7

1 INTRODUCTION......................................................................................................................................11

2 PROJECTSUMMARIES............................................................................................................................21

2.1 CALIFORNIAAMERICANWATER(CALAM)............................................................................................................22

2.2

DEEPWATERDESAL(DWD)..............................................................................................................................

242.3 PEOPLESMOSSLANDING(PML).........................................................................................................................26

3 PROJECTFUNCTION...............................................................................................................................31


3.1.1 ProjectPurpose..................................................................................................................................31

3.1.2 CustomersIdentified..........................................................................................................................31

3.1.3 AdequacyofTreatmentApproach.....................................................................................................31

3.1.4 ResidualsHandling.............................................................................................................................34

3.1.5

FeedWater

Characterization

.............................................................................................................

343.1.6 QualityofProjectInformation...........................................................................................................34

3.1.7 OmissionsorFatalFlaws...................................................................................................................35

3.2 DEEPWATERDESAL(DWD)..............................................................................................................................36

3.2.1 ProjectPurpose..................................................................................................................................36



3.2.4 ResidualsHandling.............................................................................................................................38

3.2.5 FeedWaterCharacterization.............................................................................................................38

3.2.6

Qualityof

Project

Information

...........................................................................................................

38

3.2.7 OmissionsorFatalFlaws...................................................................................................................39

3.3 PEOPLESMOSSLANDING(PML)........................................................................................................................39

3.3.1 ProjectPurpose..................................................................................................................................39



3 3 4 Residuals Handling 3 11


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INTRODUCTION MONTEREY PENINSULA REGIONAL WATER AUTHORITY

4.1.3 DisinfectionStrategy..........................................................................................................................43


4.2.1 PlantDesignCapacity........................................................................................................................44

4.2.2 TargetedProductWaterQuality........................................................................................................444.2.3 DisinfectionStrategy..........................................................................................................................45


4.3.1 PlantDesignCapacity........................................................................................................................45

4.3.2 TargetedProductWaterQuality........................................................................................................45

4.3.3 DisinfectionStrategy..........................................................................................................................46

5 ECONOMICS...........................................................................................................................................51

5.1

CALIFORNIA

AMERICAN

WATER

(CAL

AM)

...........................................................................................................

5

5


5.3 PEOPLESMOSSLANDING(PML).......................................................................................................................510

6 IMPLEMENTATIONCONSIDERATIONS.....................................................................................................61




6.3.1 AssessmentofImpactsofSeawaterIntake.......................................................................................69

6.3.2

BrineDischarge

................................................................................................................................

610

7 REFERENCES...........................................................................................................................................71

APPENDIXA....................................................................................................................................................A1

LIST OF TABLES

TABLEES1SUMMARYOFPROPOSEDPRODUCTWATERQUALITY............................................................................................4

TABLEES2

SUMMARYOFEVALUATEDCAPITALANDOPERATINGCOSTESTIMATES

.......................................................................

6

TABLE41SUMMARYOFPROJECTEDPRODUCTQUALITYFROMCALAMFACILITY...................................................................43

TABLE42SUMMARYOFPROJECTEDPATHOGENCREDITSFORCALAMPROJECT....................................................................43

TABLE43SUMMARYOFPROJECTEDPRODUCTQUALITYFROMDWDFACILITY......................................................................44

TABLE44SUMMARYOFPROJECTEDPATHOGENCREDITSFORDWDPROJECT........................................................................45

TABLE45SUMMARYOFPROJECTEDPRODUCTQUALITYFROMPMLFACILITY1......................................................................46

TABLE46SUMMARYOFPROJECTEDPATHOGENCREDITSFORPMLPROJECT.........................................................................46

TABLE51SUMMARYOFCHEMICALUNITPRICES..............................................................................................................52

TABLE52SUMMARYOFEVALUATEDCAPITALANDOPERATINGCOSTESTIMATES....................................................................54

TABLE53SUMMARYOFCAL

AMCAPITALCOSTEVALUATION.............................................................................................

56

TABLE54SUMMARYOFCALAMO&MCOSTEVALUATION...............................................................................................57

TABLE55SUMMARYOFDWDCAPITALCOSTEVALUATION................................................................................................58

TABLE56SUMMARYOFDWDO&MCOSTEVALUATION..................................................................................................59

TABLE57SUMMARYOFPMLCAPITALCOSTEVALUATION...............................................................................................510

TABLE58SUMMARYOFPMLO&MCOSTEVALUATION.................................................................................................511


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY TABLE OF CONTENTS

FIGURE21CALAMPROJECTLOCATIONMAP..................................................................................................................23

FIGURE22DWDPROJECTLOCATIONMAP.....................................................................................................................25

FIGURE23PMLPROJECTLOCATIONMAP......................................................................................................................27

FIGURE61CONCEPTUALIMPLEMENTATIONSCHEDULEFORTHECALAMPROJECT..................................................................66FIGURE62CALAMPROPOSEDIMPLEMENTATIONSCHEDULE.............................................................................................66

FIGURE63CONCEPTUALIMPLEMENTATIONSCHEDULEFORTHEDWDPROJECT.....................................................................67

FIGURE64DWDPROPOSEDIMPLEMENTATIONSCHEDULE................................................................................................68

FIGURE65CONCEPTUALIMPLEMENTATIONSCHEDULEFORTHEPMLPROJECT.....................................................................610

ABBREVIATIONS AND ACRONYMSAACE Association for the Advancement of Cost Engineering

AF Acre-Foot

AFY Acre-Feet/Year

ASR Aquifer Storage and Recovery

Cal-Am California American WaterCDPH California Department of Public Health

CEQA California Environmental Quality Act

CPCN - Certificate of Public Convenience and Necessity

CPUC California Public Utilities Commission

CRF Capital Recovery Factor

Crypto - Cryptosporidium

CSIP Castroville Seawater Intrusion Project

DWD DeepWater Desal

EA Environmental Assessment

EIR Environmental Impact Report

EIS Environmental Impact StatementEPA U.S. Environmental Protection Agency

ERD Energy Recovery Device

fps feet per second


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KHC Kris Helm Consulting

lb - pound

LF Lineal Foot

MCL Maximum Contaminant Level

MPRWA Monterey Peninsula Regional Water Authority

MRWPCA Monterey Regional Water Pollution Control Agency

mgd Million Gallons per Day

MF Microfiltration

MG Million Gallons

MLCP Moss Landing Commercial Park

MLPP Moss Landing Power Plant

MPWSP Monterey Peninsula Water Supply Project

NEPA National Environmental Policy Act

NOD Notice of Determination

NOP Notice of Preparation

NOAA National Oceanic and Atmospheric Administration

NPDES National Pollutant Discharge Elimination System

O&M Operations and Maintenance

PG&E Pacific Gas and Electric

PML Peoples Moss Landing

RO Reverse Osmosis

SCADA Supervisory Control and Data Acquisition

SDI Silt Density Index

SPI Separation Processes Inc.SVGB Salinas Valley Groundwater Basin

SWRCB State Water Resources Control Board

SWTR Surface Water Treatment Rule

TAC T h i l Ad i C mmitt


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY EXECUTIVE SUMMARY

Separation Processes Inc. (SPI) in association with Kris Helm Consulting (KHC) is providing

engineering and consulting support to the Monterey Peninsula Regional Water Authority(MPWRA) to assist with the evaluation of three candidate desalination projects on the MontereyPeninsula. This report presents the results of our evaluation of the projects, targeted at replacingsupplies currently extracted from the Carmel River but subject to a 1995 order from the StateWater Resources Control board to secure an alternate source of supply by December, 2016.

The proposed strategy for meeting the projected annual demand within the California AmericanWater service area of 15,250 acre-feet is a multi-pronged approach including permitted

extractions from the Carmel River and Seaside Basin, an aquifer-storage and recovery system,and the existing Sand City desalination plant--totaling 6,250 acre-feet; leaving a 9,000 acre-feetgap in supply. Two alternatives are under consideration to compose this final supplya 9,000acre-feet production seawater desalination plant; or a 5,500 acre-feet seawater desalination plantin concert with a groundwater water replenishment project using advanced treated recycled waterof 3,500 acre-feet.

This report presents the results of our evaluation of three candidate alternatives for the seawaterdesalination component of the overall water supply portfolio. California American Water is

actively engaged with the California Public Utilities Commission to build a facility and securethe required supply. Two other development groups have proposed alternative projects forconsiderationDeepWater Desal, LLC and the Peoples Moss Landing Water Desal Project.The three projects were analyzed on functional, performance, economic and implementationgrounds in an effort to provide a balanced evaluation for consideration by the MPRWA. Thisreport is based on information collected on each project up through October 15, 2012. It doesnot cover additional project developments between that time and the date of this report.

The three projects are in the conceptual or preliminary stage of development and all three have astheir objective to provide California American Water the seawater desal component of therequired replacement water supply under State Water Resources Control Board Order No. 95-10.The DeepWater Desal group proposes to provide an expandable plant capable of servingadditional regional water needs as well, outside of the California American Water service area.Brief summaries of the projects follow:

Proponent(s) California American Water (Cal-Am)


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Proponent(s)DeepWater Desal, LLC, Dynegy Moss Landing Power Plant,MFJK Partnership of the Capurro Ranch, PV2 Solar, andEcomert Technologies

Location Capurro Ranch Property, north of /Elkhorn Slough

PurposePhase 1 to supply supplemental desal component of theMonterey Peninsula regional water supply

Phase 2 to supply northern customers

Production VolumePhase 1: 4.9 mgd or 9.1 mgd

Phase 2: 22.0 mgd

Proponent(s)DeSal America, LLC composed of Moss LandingCommercial Park, LLC; and Stanley and Patricia-VanceLueck

LocationMoss Landing Commercial Park

Purpose

To supply supplemental desal component of the MontereyPeninsula regional water supply

This project is currently proposed as alternative to the Cal-Am MPWSP.

Production Volume4.8 mgd or 9.4 mgd

We evaluated the function of each project in terms of project purpose, customers identified,

adequacy of treatment approach, residuals handling, feed water characterization, quality ofproject information, and any omissions or fatal flaws in the information provided. Theevaluation was conducted based on information provided in response to a 56-item questionnaireprepared by the MPRWA technical advisory committee and submitted by each proponent; alongwith additional information each provided in response to specific questions and interviews fromSPI and KHC.


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by the Moss Landing Commercial Park. Cal-Am has projected there may up to 3 percent ofgroundwater from the Salinas Valley Groundwater Basin (SVGB) entrained with their intake

supply that would need to be returned (as facility product water) to the basin. For brine disposal,Cal-Am and DWD propose to blend concentrated brine from the desal plants with existingoutfall flowsCal-Am blending with the existing Monterey Peninsula Regional Water PollutionControl Agencys wastewater plant outfall; and DWD using the existing cooling water returnoutfall at the Moss Landing Power Plant. Both sources have sufficient dilution and hydrauliccapacities. PML proposes to use their existing 51-in diameter outfall, currently permitted todischarge magnesium-depleted seawater. There is some evidence of disrepair of the outfall interms of pipeline integrity and condition of the existing diffusers which would need to be

addressed along with the permitting of a non-shore diluted brine stream.

Cal-Am and PML propose to serve only the identified demand within the Cal-Am service area atthe two plant capacity increments under consideration; while DWD envisions a higher capacityregional project, capable of producing up to 25,000 AFY. DWD has not yet secured agreementswith any potential customers.

In terms of treatment approachall three candidate teams propose to use reverse osmosis (RO)as the primary desalination technology. However, both DWD and PML propose a single pass

RO system; while Cal-Am has proposed a partial double or two pass systemtreating a portionof the product water from the first pass RO system with a second RO system and blending thesupplies to form the final treated water. The issue relates to the quality of product waterproduced, more than treatment function; as either approach is considered functional.

Pre- and post-treatment approaches are similar. All incorporate granular media filtration of theincoming seawater, with PML following on with a low pressure membrane filtration system(microfiltration or ultrafiltration) to deal with the anticipated higher solids load from water

extracted from Moss Landing Harbor. In the case of Cal-Am, the aquifer filtration provided bythe slant wells could obviate the need for media filtration; but the potential presence of iron andmanganese in the supply could just as well make them necessaryso the approach is consideredconservative. In the case of DWD, the incoming seawater extracted at depth will be cold(roughly 15 C) and warmed through a proprietary warming system at the Moss Landing PowerPlant prior to transmission to the treatment plant site. All three proponents propose to use calcitebeds, carbon dioxide and sodium hydroxide for re-mineralization/stabilization of the RO treatedproduct water and chlorine disinfection.

Cal-Am and DWD will require offsite pipelines for feed, product water and brine disposal; whilePML proposes to use existing intake and outfall pipelines originating on site; requiring only aproduct water delivery pipeline. DWDs site location north of the Elkhorn Slough is likely toentail complex issues with crossings for all three of their large diameter pipelines (one 48-in andtwo 36-in).


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Importantly however, we have not found any fatal flaws of a technical nature associated with anyof the candidate projects.

Performance of each proposed system was gauged relative to categories of plant design capacity,targeted product water quality and disinfection strategy.

For plant capacity, we considered the proposed instantaneous design capacity of each treatmentfacility in comparison to the required annual production incrementeither 5,500 AFY or 9,000AFY. What we found were wide variationswith Cal-Am proposing capacities of 5.4 mgd and

9.0 mgd; DWD of 4.9 mgd and 9.1 mgd; and PML at 4.8 mgd and 9.4 mgd. We considered thelevel of equipment redundancy proposed by each team in the context of the amount of onlinetime it would require a facility at a given rated capacity to deliver the required annual allotment.For Cal-Am, we gauged their planned design capacities adequate considering the need to returnflow to the SVGB as well as meet the 5,500 AFY or 9,000 AFY into their distribution system.At capacities of 5.4 mgd and 9.0 mgd, the plant(s) would need to operate 98 percent of the timeto meet productionnot overly conservative but achievable given the level of equipmentredundancy (including spare process units) in their proposed facility. DWD, with similarproposed levels of redundancy, would have equivalent minimum facility capacity requirementsof 5.0 mgd and 8.2 mgd; somewhat lower than Cal-Am as they lack the requirement to returnflow to the SVGB. PML did not provide a detailed equipment list indicating numbers of processunits; so gauging proposed levels of equipment redundancy was uncertain. However, we feel thefacility should have adequate reliability and conducted our evaluation on that basisrecommending equivalent capacity ratings to DWD of 5.0 mgd and 8.2 mgd.

The product quality produced by the proposed systems would differ based on the configuration

of their proposed RO systems. Cal-Ams proposed partial two-pass system could likely achievechloride, boron, and total dissolved solids (TDS) consistent with current Carmel River supplies;but the single pass systems would not. We consider a lower salinity product supply an asset andevaluated all three projects (from an economic perspective) as having partial two-pass ROsystems. The recommended product quality goal is summarized in Table ES-1.

Table ES-1 Summary of Proposed Product Water Quality

Total Dissolved Solids mg/L 380

Chloride mg/L 60

B /L 0 5


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For disinfection, the proposed facilities must comply with the Surface Water Treatment Rule andLong-Term 2 Enhanced Surface Water Treatment Rule. Under these regulations, pathogen

removal/inactivation requirements are set on a logarithmic (log) scale, with the CaliforniaDepartment of Public Health establishing specific log removal for priority pathogens, includinggiardia, cryptosporidium (crypto), and virus. The levels set will be based on source water qualityand other factors, and are expected to be in the range of 3-5 for giardia, 2-4 for crypto, and 4-6for virus, based on each of the project source waters being classified as surface waters or underthe influence of surface waters. We find all three projects are likely to achieve sufficient logremoval credits under their proposed treatment schemes to comply.

A primary focus of our evaluation was to provide a balanced, apples to apples comparison ofthe candidate projects from an economic perspective. We implemented this by focusing on thefollowing principles:

Uniformity in plant design capacity for the two non-regional approaches; equivalentcapacity allocation for the proposed DWD regional project.

Equivalency in treatment to achieve: a common RO feed water quality followingpretreatment; a common treated water quality goal; and pathogen removal creditsrequired for the applicable supply source.

Uniformity in equipment redundancy. Uniformity in unit cost criteria for common items. Uniformity in cost factors applied to aggregated costs (e.g., contingencies; electrical

and I&C costs; etc.).

Uniformity in unit costs for chemicals and other consumables for treatmentevaluations.To implement the above, we adjusted plant capacities for the evaluation on the basis described inthe Project Performance discussion, rating Cal-Ams proposed system at design capacities of 5.4mgd and 9.0 mgd; and the DWD and PML systems at 5.0 mgd and 8.2 mgd. In terms oftreatment process, we attempted to maintain the overall proposed process design of theproponents, but did evaluate all as including a partial (40 percent) capacity second pass ROsystem. We also assumed N+1 redundancy on all rotating equipment and major treatmentprocess units (e.g., filters, RO membrane trains). We employed an equivalent basis indeveloping our capital equipment cost estimates, relying on targeted quotes for equipment andSPIs cost information from past, similar seawater RO projects. For indirect costs, we assumedfixed factors and applied them uniformly to each project.

We implemented a similar strategy on annual operating and maintenance expenses, using


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Table ES-2 - Summary of Evaluated Capital and Operating Cost Estimates

Intake/Outfall Facilities $23.0 $17.7 $-0- $-0- $-0- $-0-

Pretreatment & Residuals Handling $10.6 $7.94 $11.2 $7.94 $20.2 $13.6

Desalination System $22.4 $15.0 $19.4 $13.2 $19.9 $14.0

Post-Treatment $1.48 $0.88 $1.48 $0.88 $1.66 $1.07

Distribution Facilities $6.14 $5.08 $3.35 $3.26 $0.35 $0.26

Site Structures $11.5 $10.8 $3.65 $2.52 $10.0 $7.00

Offsite Trenched Pipelines $24.9 $24.9 $28.3 $27.3 $25.1 $25.1

Indirect Costs1 $57.5 $50.3 $54.5 $47.5 $67.9 $62.3

Contingency Allowance (30%) $47.2 $39.8 $36.6 $30.8 $43.6 $37.0

Mitigation Allowance (1%) $1.60 $1.30 $1.20 $1.00 $1.50 $1.20

Energy $5.38 $3.26 $3.73 $2.29 $3.98 $2.43

Chemicals $0.32 $0.19 $0.81 $0.49 $0.93 $0.57

Expendables $0.69 $0.45 $0.78 $0.52 $1.09 $0.65

Other Proponent Expenses -- -- $1.59 $1.45 -- --

O&M Labor $2.69 $2.36 $2.69 $2.36 $2.69 $2.36

Equipment Replacement2

$1.50 $1.23 $1.01 $0.83 $1.16 $0.92

Capital Recovery3 $19.1 $16.2 $9.25 $7.75 $11.0 $9.37


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Overall, the projected capital and operating costs for each facility are fairly equivalent given theoverall accuracy of the estimate and degree of project development. Cal-Ams capital cost is the

highest; owing largely to its high intake system cost. PML is proposing to reuse existing intakeinfrastructure; while DWD has an unspecified separate business entity which will be funding itsintake, outside of the assigned DWD facility budget. Cal-Ams operating cost is also relativelyhigh, owing in large measure to higher stipulated energy costs than either DWD or PMLroughly $0.13/kW-hr vs. $0.08 kW-hr. The overall water production costs diverge considerablyin our evaluation, due to the higher cost of capital assigned to Cal-Am vs. DWD and PML; sowhile the base costs are similar, Cal-Ams cost of water produced is higher. An expandeddiscussion of how the capital recovery factor (CRF) for Cal-Am was generated is presented in

Section 5.

The three projects are at varying states of development in terms of the regulatory permittingprocess. Cal-Am is further along than either DWD or PML, though DWD has completed or isnearing completion of their initial CEQA compliance documents. Forecast projectimplementation schedules were identified for each project proponent, based on a select number

of key environmental and permitting tasks, including:

1. A project description must be completed.2. An Environmental Assessment must be made.3. An EIR/EIS must be completed (CEQA/NEPA compliance).4. Commercial Agreements must be negotiated/ Cal-Am must obtain a Certificate of Public

Convenience and Necessity (CPCN), after certification of the EIR.

5. Jurisdictional Permits must be obtained for facilities impacting Waters of the U.S.6. NPDES Permits must be amended/obtained.7. Coastal Development Permits must be obtained.

It was further assumed that each proponent had the financial capacity to proceed with predesignpreparation/procurement package development such that the project could be put out to finaldesign and construction bid coincident with approval of the final project permits. The schedules

are provided below as , Figure ES-2 and Figure ES-3. The project proponents were invited toprovide their updated schedules following publication of the draft report. Cal-Am and DWDeach elected to provide a schedule, which are included in Section 6.


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Figure ES-1 Projected Cal-Am Project Implementation Schedule

Figure ES-2 Projected DWD Project Implementation Schedule

Figure ES-3 Projected PML Project Implementation Schedule


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY INTRODUCTION

1 INTRODUCTIONSeparation Processes Inc. (SPI) and Kris Helm Consulting (KHC) are providing engineering andconsulting support to the Monterey Peninsula Regional Water Authority (MPWRA) to assistwith the evaluation of three candidate desalination projects on the Monterey Peninsula. SPIconducted technical and economic evaluations of the proposed projects; while KHC examinedissues relating to permitting and environmental compliance.

California American Water (Cal-Am) is an investor owned public utility who is responsible forproviding the water supply to cities covered within the MPRWACarmel-by-the-Sea, Del Rey

Oaks, Monterey, Pacific Grove, Sand City and Seaside. The proposed projects wouldsupplement supply previously extracted for the region from the Carmel River. In 1995, the StateWater Resources Control Board (SWRCB) in its Order No 95-10 found that Cal-Am waswithdrawing water from a subterranean stream, rather than percolating groundwater; and in theprocess extracting an average of 10,730 AFY in excess of its valid right of 3,376 AFY. Theorder required Cal-Am to secure a replacement source of supply by December 2016.

The average annual water demand in the region is 15,250 AFY1. Currently identified sources

include established rights to Carmel River and Seaside Basin waters of 4,850 AFY, the aquiferstorage and recovery (ASR) system of 1,300 AFY, and 94 AFY from the Sand City DesalinationPlant. This leaves a roughly 9,000 AFY deficit to be made up. Alternatives include a new 9,000AFY seawater desalination plant; and a new groundwater replenishment (GWR) project of 3,500AFY in combination with a new 5,500 AFY seawater desalination plant.

The technical advisory committee (TAC) of the MPRWA developed a list of 56 questions tosubmit to the three desalination project proponents, including Cal-Am, DeepWater Desal, LLC(DWD) and the Peoples Moss Landing Desal (PML). Each proponent is proposing to build a

desalination facility to satisfy the planned desalination component of the regional water supply.Responses and supporting information were received from each, exhibiting various stages ofdevelopment and differences in approach. The differences were such that a deliberative, faircomparative evaluation could not be conducted solely on the basis of the information provided.

This report presents the results of a more detailed evaluation and analysis conducted by SPI andKHC. The work was conducted based on information provided in the original responses to thequestions from the TAC along with supplemental information provided by each proponent. The

goal was to provide an apples-to-apples comparison of each project on an equivalent costbasis; along with an evaluation of the realistic implementation schedule for each, taking intoaccount environmental and permitting issues.


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY PROJECT SUMMARIES

The tabular summaries provided in this section include information on each of the proponentprojects, including:

Project name Proponent(s) Location Purpose Production volume Key features Facility map Key information provided to review team Persons interviewed/corresponded with

The TAC requested information from each proponent that would satisfy the desalinationcomponent of the proposed water supply. Responses received from the Cal-Am and PMLgroups were generally in line with this request; though there were slight differences in theproposed plant capacities. The DWD response proposed to only serve the higher 9,000 AFYrequirement, along with a planned expansion to act as a regional water supply source to otheragencies on the peninsula as well as cities north of Moss Landing. DWD did reveal in response

to subsequent inquiries how they would serve the 5,500 AFY supply scenario. The informationpresented for each project represents their current status from the proponents at the time of thisreport writing.


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PROJECT SUMMARIES MONTEREY PENINSULA REGIONAL WATER AUTHORITY

Project Name Monterey Peninsula Water Supply Project

(MPWSP)

Proponent(s) California American Water

Location 46-acre site of vacant, disturbed land west of theMRWPCA Regional Treatment Plant (RTP).

Purpose To supply supplemental desal component of theMonterey Peninsula regional water supply

This project is currently under consideration by theCalifornia Public Utilities Commission (CPUC).

Production Volume 5.4 mgd or 9.0 mgd

Key Features 1.Raw seawater supply through a series of up toeight sub-surface slant wells located on a vacant376 acre parcel with roughly 7,000 feet of oceanshoreline.

2.Raw water and pump to waste transmissionthrough one of eight candidate alignments.

3.Single-stage, dual media pressure filtrationpretreatment.

4.Partial 2-pass RO desalination treatment withenergy recovery. Final product has a proposedblend of 60:40 first pass:second pass product.

5.Product stabilization with calcite, carbon dioxide,and sodium hydroxide.

6.Disinfection with sodium hypochlorite andtemporary UV.

7.2 x 1.0 MG product storage tanks, productdistribution pumps, and 36-in diameter productpipeline to Cal-Am distribution system nearSeaside.

8.24-in brine disposal pipeline to the existing RTPoutfall.

Key Information Provided 1.TAC response package2.Response to supplemental questions from SPI

and KHC3 Relevant testimony to the CPUC


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Figure 2-1 Cal-Am Project Location Map

____Slant Well

____ Intake

____ Brine

____ Product Water

Desalination Plant

Tie-in to CAL AMexisting facilities


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Project Name DeepWater Desal

Proponent(s) DeepWater Desal, LLC, Dynegy Moss LandingPower Plant, MFJK Partnership of the CapurroRanch, PV2 Solar, and Ecomert Technologies

Location Capurro Ranch Property, north of /Elkhorn Slough

Purpose Phase 1 to supply supplemental desal component ofthe Monterey Peninsula regional water supply

Phase 2 to supply northern customersProduction Volume Phase 1: 4.9 mgd or 9.1 mgd

Phase 2: 22.0 mgd

Key Features 1. Raw seawater supply through a new 48-in openintake extending into the Monterey Bay west ofMoss Landing at a depth of roughly 65-ft.

2. Raw water transmission through an existingright of way maintained by MLPP to an existingpump station at MLPP for transfer to the site.

3. Proprietary warming system at MLPP whichwill increase the temperature of the raw water.

4. Transmission of the warmed feed water througha new 36-in pipeline to the Capurro Ranch site.

5. Single-stage, dual media pressure filtrationpretreatment.6. Single-pass RO desalination treatment withenergy recovery.

7. Product stabilization with calcite, carbondioxide, and corrosion inhibitor.

8. Disinfection with sodium hypochlorite.9. 2.5 MG product storage tank, product

distribution pumps, and 30-in diameter product

pipeline to Cal-Am distribution system nearSeaside.

10.36-in brine disposal pipeline to MLPP existingcooling water ocean discharge.

Key Information Provided 1.TAC response package2 R l l i f SPI


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Figure 2-2 DWD Project Location Map

____Intake

____ Brine

____ Product Water

Desalination Plant

Tie-in to CAL AMexisting facilities


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Project Name The Peoples Moss Landing Water Desal Project

Proponent(s) DeSal America, LLC composed of Moss LandingCommercial Park, LLC; and Stanley and Patricia-Vance Lueck

Location Moss Landing Commercial Park

Purpose To supply supplemental desal component of theMonterey Peninsula regional water supply

This project is currently proposed as alternative tothe Cal-Am MPWSP.

Production Volume 4.8 mgd or 9.4 mgd

Key Features 1. Raw seawater supply through an existing intakesystem drawing from the Moss Landing Harbor.

2. Single-stage, zeolite pressure filtration followedby ultrafiltration (UF) pretreatment.

3. Single-pass RO desalination treatment withenergy recovery.4. Product stabilization with calcite, carbon

dioxide, and sodium hydroxide.5. Disinfection unspecified, but presumed to be

with sodium hypochlorite.6. Product storage in existing site tankage. New

distribution pump station and 36-in diameter

product pipeline to Cal-Am distribution systemnear Seaside.

7. Brine disposal through existing 51-in (internaldiameter) outfall.

Key Information Provided 1.TAC response package2.Project information package dated July 20123.Response to supplemental questions from SPI

and KHC4.Video of a portion of the existing outfall.5.August 2012 Structural Evaluation Report of site

structures and outfall, conducted by JAMSEEngineering, Inc.

6 Construction drawings for the outfall (1973) and


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Figure 2-3 PML Project Location Map

____Intake

____ Brine

____ Product Water

Desalination Plant

Tie-in to CAL AMexistin facilities


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MONTEREY PENINSULA REGIONAL WATER AUTHORITY PROJECT FUNCTION


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The function of each proponent project is evaluated on the following criteria:

Project purpose Customers identified Adequacy of treatment approach Residuals handling Feed water characterization Quality of project information Omissions or fatal flaws

In an initial screening level evaluation2, we found no disqualifying criteria for any of thecandidate projects. We did however find differences in the level of project development andapproach. Each project is discussed separately below.

3.1.1 Project PurposeCal-Am proposes their project to serve the needs of the identified demand on the MontereyPeninsula within their service area to comply with SWRCB Order 95-10. The proposedtreatment plant would serve the identified desalination component of the regional water supplyportfolio. They specifically do not propose to provide a plant capacity in excess of defined

regional water supply requirements under two scenarioswith GWR and without GWR

3

.

3.1.2 Customers IdentifiedTreated water would be supplied to the Cal-Water distribution system for service to its currentservice area. Any groundwater from Salinas Basin drawn through the proposed supply wellswould be returned the basin as plant treated water through the Castroville Seawater IntrusionProject (CSIP) ponds3.

3.1.3 Adequacy of Treatment ApproachFeed water for the desalination plant would be extracted from subsurface slant wells. Over thelong term, feed water is projected to include about 97 percent seawater and 3 percent intruded

3

PROJECT FUNCTION MONTEREY PENINSULA REGIONAL WATER AUTHORITY


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The preferred site for construction of the slant wells is an approximately 376 acre parcel of landwith 7,000 feet of ocean shoreline, located west of the proposed desal plant site. The angle of theslant wells will be determined by a proposed test well program, with a maximum well length ofapproximately 750 lineal feet. Wells would initially be placed on the beach, as far as possiblefrom the existing shoreline, but avoiding undisturbed dune habitat. This may cause some or allwells to be within the predicted 50-year erosion boundary; however, the expected useful life ofthe wells is less than 50 years. A contingency plan will be needed for relocating the wells inlandin the event that coastal erosion renders the wells inoperable4.

Two design capacities are proposed: (1) seven wells operating at 2,200 gpm per well plus oneadditional well as a backup, for a total of 22 mgd (15,400 gpm) producing 9.0 mgd of product

water; (2) five wells operating at 1,840 gpm per well plus one additional well as backup, for atotal of 13.2 mgd (9,200 gpm) producing 5.4 mgd of product water4.

Eight feed water pipeline alignments are being considered, all of which will be made of HDPE orFPVC, and will have a 30-inch or 36-inch diameter. The final selected alignment would includea parallel 16-in diameter pump to waste pipeline, to allow wasting of initial produced water froma pump following startup.

The proposed treatment plant would be located on a vacant but disturbed 46-acre parcel west of

the MRWPCA Regional Treatment Plant (RTP). The site would be accessed off of CharlesBenson Rd., a two-lane roadway that also serves the MRWPCA RTP along with the MontereyRegional Waste Management District. Access would be via an easement from the WasteManagement District. A new turn lane would need to be provided to allow safe access to theproposed desal plant for personnel and chemicals deliveries. Cal-Am is currently in negotiationsto purchase the site from the existing land owner. Overall, land acquisition is not a large concernas Cal-Am has the authority to exercise eminent domain privileges should a negotiated purchaseprove untenable.

Incoming seawater would be stored in two 0.5 MG storage tanks then pumped to granular mediapressure filters. Provisions would be included to pre-chlorinate the filter feed if necessary; aswell as include proprietary media to remove iron and manganese should it be present in the rawseawater. Filter effluent would be dechlorinated if necessary, then flow to inline cartridge filtersprior to routing to the RO trains. The proposed RO system would be arranged as a full singlepass and partial second pass; with the second pass product making up 40 50 percent of the finalproduct supply. The first pass trains would include high pressure booster pumps and isobaric

energy recovery devices (ERDs); while the second pass trains would be equipped with highpressure booster pumps only. Operating recovery of the first pass trains would be roughly 45.5percent; while the second pass trains would operate at 90 percent. First and second pass trains,related pumps, and ERDs would be arranged in an N+1 configuration, with a total of fourprocess trains for the 5.4 mgd plant option and six process trains for the 9.0 mgd plant option.

5



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Overall the treatment approach is gauged to be sound. The greatest process risk is likelyassociated with the proposed slant wells. Slant well intake systems can provide significantadvantages over traditional open ocean intakes including:

Natural filtration Avoidance of impingement and entrainment of marine life No ocean construction impacts No permanent aesthetic impacts.

However, slant wells can also pose more construction challenges than other well types as a result

of shallow construction angles and less vertical gravitational force. Slant wells need periodicaccess to the well head area. In areas where recreation exists (e.g., at a public beach) provisionmust be made to minimize disturbance6. Slant well intakes can be used with large desalinationplants, with seawater intake capacities of up to 50 mgd7. Maintenance of well specific capacitylong term is unknown; and elsewhere where employed the wells have been known to initiallydraw from an ancient marine aquifer containing high levels of iron and manganese 8. Lastly, thespecific long term amount of groundwater uptake from the SVGB, estimated at up to 3 percent,is uncertain.

Cal-Am plans to install a test slant well to establish site specific operating conditions andgenerate data which should help to confirm actual conditions and allow development ofappropriate mitigation strategies. Cal-Am has already included provisions for removing iron andmanganese across their pretreatment filters if necessary. The slant wells themselves can bescreened or installed at different angles to control the mix of seawater to diluent water extracted.Cal-Am is currently pursuing permits for the test well. An initial operating period of 6 12months is planned to develop data required for the EIR CEQA work. Cal-Am has indicated that

the test period could extend as long as 18-24 months if additional data is required5

. Should thetest well reveal slant wells to be problematic, a more conventional Ranney sub-surface intakewell could be used as an alternative. The conceptual layout would include three vertical caissonsand horizontal well clusters located across a 1,000 1,500 feet beach front area. Each caissonwould be capable of extracting up to 10 mgd. Costs would roughly equivalent to the proposedslant wells; however, shoreline disruption would be greater.

With either intake system, delivered raw seawater quality is likely to be good, with low

particulate and silt density index (SDI) levels, making single-stage filtration an acceptablepretreatment approach. The RO process design is conservative, with a full first pass and partialsecond pass; including N+1 redundancy for all process units. The proposal does not includeacidification or antiscalant dosing to the first pass RO system feed water, but this is likelyacceptable as the planned recovery of the first pass system is limited to 45 percent. Feed andproduct storage tanks are arranges as 2 x 50 percent units, allowing the ability to take a tank out



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of service for maintenance. A preliminary site plan indicates the proposed site is sufficient toaccommodate the proposed treatment plant facilities and related administrative and maintenancefacilities adequately.

3.1.4 Residuals HandlingPlant residuals would be handled in a combination of storage and transfer systems. Backwashwaste from the filters would be collected in a 0.5 acre storage pond, with decant disposed withthe RO brine. RO brine would be sent to the MRWPCA ocean outfall. Analyses have shownthat the outfall has sufficient capacity to accommodate the projected peak brine flow from the

plant under all but a worst case hydraulic loading scenario that is anticipated to last for sixhours9. In these situations, brine would temporarily be stored on site in a 3.0 MG detentionpond. The majority of the time (96 percent) the outfall is projected to have sufficient capacity.Waste residuals from the RO cleaning system would be neutralized and discharged with the brineto the outfall as well; or alternately to the site sanitary sewer if disposal with the brine is notpermitted.

3.1.5 Feed Water CharacterizationThere has been no detailed characterization of plant feed water to date. Data will be generated aspart of the planned test well program.

3.1.6 Quality of Project InformationAvailable documentation for the Cal-Am project is the most extensive and well developed

among the three proponents. Primarily this is a consequence of their involvement in thepreviously proposed regional project with Marina Coast Water District along with filings to theCPUC supporting their proposed project and development of required CEQA documentation.Appendices to their response to the TAC included the following:

RBF Memorandum, Monterey Peninsula Water Supply Project (MPWSP) Capital andO&M Cost Estimate Update, April 20, 2012.

RBF Memorandum, Monterey Peninsula Water Supply Project (MPWSP) ProjectDescription, April 20, 2012.

Direct Testimony of Jeffrey T. Linam Before the Public Utilities Commission of theState of California, Filed April 23, 2012.

Other project related documents were available on the Monterey Peninsula Water Supply Projectb it i l di



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Presentations, including Technical Workshops on Monterey Peninsula Water SupplyProject (July 2012); Monterey Peninsula Water Supply Project Presentation (April2012); and Monterey Peninsula Water Supply Project Presentation (July 2012).

Project Map (April 23, 2012). California American Water Application for Monterey Project (PDFA) California American Water Application for Monterey Project (POS, NOA,PDFA) California American Water Direct Testimony of Keith Israel, including a Technical

Memo from Trussell Technologies, MRWPCA Outfall Hydraulic Capacity Analysis,

April 18, 2012 California American Water Direct Testimony of Jeffrey T. Linam California American Water Direct Testimony of Eric J. Sabolsice California American Water Direct Testimony of F. Mark Schubert, P.E. California American Water Direct Testimony of David P. Stephenson California American Water Direct Testimony of Richard C. Svindland California American Water Direct Testimony of Kevin Thomas

Cal-Am also provided a response to questions from SPI, including the following documents:

Capital Cost Worksheet O&M Cost Worksheet RBF Memorandum, Implementation Schedule Risk Analysis of Water Supply

Alternatives, October 24, 2011

RBF Memorandum, Cost Analysis of Water Supply Alternatives, October 19, 2011Overall the information is considered sufficient to evaluate the proposed project from a technicaland economic perspective.

3.1.7 Omissions or Fatal FlawsOur evaluation and investigation of the proposed Cal-Am project did not uncover any perceivedfatal flaws of a technical nature or significant omissions of project information.



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3.2.1 Project PurposeDWD proposes a project that could serve both the defined demand within the Cal-Am servicearea for a desal supply of either 5,500 AFY or 9,000 AFY along with an expanded supply for theregion with a total plant capacity of 25,000 AFY. The project is predicated on development ofcertain components (e.g., the seawater intake, feed pipeline, brine pipeline) for the 25,000 AFYplant, with cost allocation based on treated water flow to defined customers. DWD plans toestablish a joint powers authority (JPA) composed of local public agencies to ultimatelyprosecute its project.

3.2.2 Customers IdentifiedDWD seeks to supply either 5,500 AFY or 9,000 AFY to Cal-Am. The balance of the proposedplant capacity would be supplied to other customers. These may include the City of Santa Cruz,Soquel Creek Water Distict, Pajaro Valley Water Management Agency, areas of North MontereyCounty which may have a need and communities along the Highway 101 corridor betweenSalinas and Santa Clara.

3.2.3 Adequacy of Treatment ApproachDWD proposes two plant design capacities to meet the 5,500 AFY and 9,000 AFY deliverytargets4.9 mgd and 9.1 mgd. Each of these capacities is different than the Cal-Am listed flowsof 5.4 mgd and 9.0 mgd, respectively.

DWD proposes a new passive-screened open seawater intake drawing from Monterey Bay nearMoss Landing. Feed water would be withdrawn from a new 48-in. diameter pipe that wouldreplace an existing pipeline previously used by PG&E for offloading fuel oil. The intake pipewould be 10,000 feet long and located at a depth of approximately 65-ft at its end. The pipe

terminus would be screened with a passive, cylindrical wedge-wire screen constructed with 2mm. slot openings and a maximum design velocity of 0.5 fps through the screen to preventimpingement of marine organisms.

The intake would cross Hwy. 1 through an existing utility tunnel; or space not permitting, a newcrossing. The line would connect to an existing, abandoned pump clear well at the Dynegy MossLanding Power Plant (MLPP). New pumps would be installed to transfer the influent seawaterfrom the clear well through a new 48-in diameter HDPE pipeline to the project site located

roughly one mile north of MLPP along Hwy. 1, a location known as the Capurro Ranch. Enroute to the site, the water would transition through a proprietary warming system owned byDynegy, increasing its temperature from roughly 10 C up to as high as 34 C.

The project site is currently occupied by an active vegetable distribution facility, with two large,refrigerated buildings on-site. The site is currently owned by MFLK Partnership, who are also

i i D W D l LLC DWD h d 34 d l f h i



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necessary, then flow to inline cartridge filters prior to routing to the RO trains. The proposed ROsystem would be arranged as a single pass system. The trains would include high pressurebooster pumps and isobaric ERDs. Operating recovery of the first pass trains would be variablebetween 43 and 47 percent. The RO trains, related pumps, and ERDs would be arranged in anN+1 configuration, with a total of three process trains for the 4.9 mgd plant option and sixprocess trains for the 9.1 mgd plant option.

10

The product water from the RO system would be post-treated with calcite and carbon dioxide forstabilization, along with addition of a corrosion inhibitor. For disinfection, the product would bedosed with sodium hypochlorite and stored in a single 2.5 MG storage tank.

Overall the treatment approach is gauged to be sound, though the proposed RO system designwould produce a lower quality product than the proposed Cal-Am system, consisting solely of asingle pass of RO treatment. The greatest process risk is likely associated with the proposedopen intake and feed water delivery system. Water quality sampling conducted at depth hasindicated the raw seawater will likely be low in turbidity and suspended solids. This is backedup by available literature. Intake depth can have a significant impact on water quality. Sun raysare absorbed by the ocean surface, limiting photosynthesis and algae quantity as depth increases.It is for this reason that deep water intakes typically provide feed water with less biological

activity and fewer suspended solids than conventional open water/surface intakes. However, thedisadvantage is that seawater temperature decreases with depth, increasing either membranesurface area or feed pressure required for treatment. On the other hand, more stable annualtemperatures at this depth may facilitate plant design and operation11. To address thetemperature issue, DWD has proposed warming the supply in proprietary system on the MLPPsite. The proposed system is subject to a non-disclosure agreement at present, limiting thepublicly available information. However, it appears the system will likely be integral tooperations at the MLPP, providing a cooling water source. The approach is certainly synergistic,but it also in effect links operations between MLPP and the desal plant to a certain extent,introducing potential reliability issues. In addition, there is no experience with the effect ofwarming a deep source supply. There is potential for the increase in temperature to cause anincrease in biological activity and associated biological fouling within the treatment process.There is no way to gauge the potential magnitude of this risk element at this time. The DWDproject proponents do not consider it a large concern and have not proposed a pilot test programon the candidate source water and overall pretreatment process. The issue becomes what would

be the impact of a problem discovered once the project was built? Remedies may be limited ifthe warming process is contingent on an agreement between Dynegy and DWD. If the warmingprocess could be bypassed, then the issues with cold water treatment would come into play,increasing RO system operating pressures and potentially exceeding operating capabilities ofinstalled pumping equipment.

Th RO d i f i i i i i h N 1 d d f



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storage could be obtained. A preliminary site plan indicates the proposed site is sufficient toaccommodate the proposed treatment plant facilities and related administrative and maintenancefacilities adequately.

From a process perspective, the proposed pretreatment system design is likely acceptable. Thereis sufficient precedence for single stage filtration on open seawater intakes among successfullyoperating facilities to provide confidence in this approach12. The proposal does not includeacidification or antiscalant dosing to the first pass RO system feed water, but this is likelyacceptable if recovery is limited to the proposed operating range. A larger concern is with theRO system process design as a single pass system which would produce a treated product supplywith TDS, boron and chloride levels above the existing supplies from the Carmel River. It is our

recommendation that any desalination system incorporating RO as the primary process forPeninsula customers include a partial (at least 40 percent) second pass RO system to furtherimprove product quality, especially at the elevated temperature operation proposed.

3.2.4 Residuals HandlingBackwash waste from the filters would be collected in a 175,000 gallon settling tank, with decantsent to a separate 150,000 gallon tank for disposal along with the RO brine. RO brine would besent to back to MLPP for disposal along with the plant cooling water through their existing oceanoutfall at a projected dilution ratio between 20 and 60 to 1. DWD also proposes to neutralizechemical cleaning wastes and dispose of them with the brine as well.

During our site visit it was made clear that an agreement between DWD and Dynegy for use ofthe cooling water outfall was still subject to negotiation among the parties.

3.2.5 Feed Water CharacterizationDWD has a buoy in the area of the proposed intake collecting data on salinity, temperature andturbidity at fixed intervals. Comprehensive analytical data is not available at this time. DWDhas retained Tenera Environmental to conduct a 12 month study on impingement andentrainment issues. Sampling in support of the study is ongoing. Tenera did conduct apreliminary analysis based on available information and a proposed intake flow of 25 mgd. Thatreport found low projected levels of entrainment. However, additional more detailed analysesare required based on site specific data; in particular to assess the presence of a large, verticalmixing zone at the interface of the submarine canyon in the bay13.

3.2.6 Quality of Project InformationAvailable documentation for the DWD project is adequate at this stage of project development.DWD has not yet progressed with their formation of a joint powers authority (JPA) for projectimplementation and production of environmental permitting packages. Information collected tod h l l b i i f d fi i h j h i d



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A listing of documents provided in addition to the response to the TAC is as follows:

Product Water Pipeline Alignment Intake Pipeline Hydraulic Grade Line Draft Design Criteria Tenera Preliminary Intake Assessment Conductivity, Temperature and Turbidity Data May 30 June 12, 2012. Raw Water Characterization Program Memo Capital and O&M Cost Estimate Worksheets Site Layout for Capurro Ranch Presentation: An Oceanographic Solution to Product Freshwater, August 2012

Overall the information is considered sufficient to evaluate the proposed project from a technicaland economic perspective.

3.2.7 Omissions or Fatal FlawsWe have not identified any fatal flows of a technical nature with the DWD proposed system.The only omissions of information are acknowledged by DWD and related to the agreementsbetween DWD and Dynegy.

3.3.1 Project PurposePML proposes a project that could serve the defined demand within the Cal-Am service area fora desal supply of either 5,500 AFY or 9,000 AFY.

3.3.2 Customers IdentifiedPML seeks to supply either 5,500 AFY or 9,000 AFY to Cal-Am. Supply to other customers isnot proposed.

3.3.3 Adequacy of Treatment ApproachPML proposes two plant design capacities to meet the 5 500 AFY and 9 000 AFY delivery



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Harbor and supplies water to the site through two 36-in diameter pipelines that cross beneathHwy. 1 through a pair of 72-in corrugated steel conduits. One of the pipelines has beenupgraded to steel throughout its length; while the second maintains a section of the original wood

staved piping on site. Proponents have also indicated the ability to repurpose the existing siteseawater outfall as dual intake-outfall conduit extending into the Monterey Bay out front of MossLanding Harbor. The existing concrete outfall is 51-in internal diameter; and could have a newintake line installed in the annular space; with brine flowing out in the opposite direction. Costestimates provided to SPI were based on use of the existing intake system so this approach formsthe basis of our evaluation.

The 1968 drawings show the installation of seven pumps. The condition of the pumps at this

time is unknown; but would likely require rehabilitation and rework to supply the proposedtreatment plant. The pump bowls reportedly draw from below the harbor seafloor, but the actualdepth is unknown.

The MLCP site still contains infrastructure from the time it was employed as a magnesiumextraction facility. The total site occupies roughly 200 acres; with a proposed 25 acre parceloffered for sale or lease as part of the proposed desal treatment plant. Available facilities offeredfor use include the following:

Intake pumps and pipeline and outfall pipeline. Up to four 5.0 MG concrete storage tanks. A 12kV, 12,000 amp electrical service along with two 1,000 amp engine generators. Rail transportation terminal. Non-exclusive easements for site access. Non-exclusive use of a 2,100 gpm well supply source. A 5,000 gpd trailer-mounted pilot plant. Up to 20,000 sq. ft. of existing buildings.

Existing infrastructure is in various states of repair as detailed in two site investigations14,15andwould require some refurbishment and rework to be acceptable for integration into a municipaldrinking water facility. Portions of the site are likewise located within the flood plain16 andconstructed facilities would need to be built in accordance with any ensuing requirements.

The proposed PML treatment system would include inlet screens, booster pumps, single stagepressure filters, an ultrafiltration (UF) membrane treatment system, antiscalant dosing system,high pressure booster pumps with pressure exchange type ERDs, single pass RO system, post-treatment system, and product storage and distribution pump station. The RO system wouldoperate at 40 percent recovery and limit operating flux to 8 gfd The UF system would operate at



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The product water from the RO system would be post-treated with calcite and carbon dioxide forstabilization, along with addition of a corrosion inhibitor. For disinfection, the product would bedosed with sodium hypochlorite and stored in existing tankage on site.

PML did not provide a detailed list of equipment or a site layout plan, stating that it was too earlyin the development of their project to have that information developed. It is therefore somewhatdifficult to gauge the robustness of their approach. From the narrative description provided andlisted membrane area assumptions, it is not clear that the major UF and RO train equipmentcontain redundant process units.

From a process perspective, the proposed pretreatment system design may be acceptable. Thelargest unknown is the quality of water that will be extracted from the Moss Landing Harbor.There could be organics, metals and other contaminants entrained in the sediments overlayingthe supply pumps that could complicate treatment. PML has proposed conducting a pilot studyprogram prior to finalizing their process design, so this should help allay concerns. A previouspilot study conducted at MLPP found that direct UF pretreatment operated in concert with acoagulant was effective at pretreating a supply drawn from the Moss Landing Harbor, but thatflux should be limited to 30 gfd17.

A larger concern is with the RO system process design as a single pass system similar to theDWD approach. As stated in that discussion, we recommend including a partial second pass ROtreatment system to produce a final product quality more in keeping with current supplies in thedistribution system.

3.3.4 Residuals HandlingPretreatment residuals would come from the proposed filters and UF process units. A backwashrecovery system is proposed, with decant sent to the outfall with the RO system brine stream.Neutralized UF and RO cleaning wastes would be treated similarly; or recovered for reuse withinthe MLCP. Brine would be discharged to the existing outfall.

The outfall is currently not in use and there is evidence of disrepair in a video survey conductedsometime prior to 200818 . The video shows evidence of several areas of decoupling along themain outfall alignment. Also, according to the original plans, the outfall was installed belowgrade until the diffuser section19. However, portions of the main outfall appear to be currently

uncovered; and one section shifted uppossibly as a consequence of the 1989 Loma Prietaearthquake. Many of the diffusers are clogged and covered with marine growth; and from theterminus of the outfall it appears it may be largely filled with sandup to half of thecircumference. Consequently a fair amount of rehabilitative work would be required to place theoutfall into service, and more detailed assessmentincluding an inspection of the interior of the



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3.3.5 Feed Water CharacterizationPML does not at this point have analytical data characterizing the proposed raw water supply. It

will presumably be collected during their planned pilot test program.

3.3.6 Quality of Project InformationThe PML project is the least developed among the three as evidenced by the level of informationprovided. They were however very forthcoming in sharing all that was available, includingoriginal construction plans for the intake and outfall, video survey of the outfall, and other sitespecific reports.

A listing of documents provided in addition to the response to the TAC is as follows:

Construction Plans: Seawater Outfall Construction Plans: Relocation of Sea Water Intake The Peoples Moss Landing Water Desal Project, Important New Updates, July 2012 Response to SPI Questions, September 4, 2012 and September 27, 2012 Environmental Issues and Constraints Report, SMB Environmental, September 2012 Structural Evaluation, JAMSE Engineering Inc., August 2012. Replacement Cost Appraisal Summary Report, Landmark Realty Analysts, Inc.,

October 2011.

Adopted Waste Discharge Requirements Order No. R3-2009-002, National PollutantDischarge Elimination System (NPDES) Permit No. CA0007005 Moss Landing

Commercial Park and Moss Landing Cement Company, Moss Landing CementCompany Facility, Monterey County, March 2009.

Overall, the lack of specificity as to the proposed plant facilities makes the technical andeconomic evaluation difficult and forces us to make additional assumptions on our own.

3.3.7 Omissions or Fatal FlawsWe have not identified any fatal flows of a technical nature with the PML proposed system. Theprimary omission is the lack of defined lists of equipment in order to assist in validating costestimates.

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This section discusses the following performance issues for each project:

Plant design capacity Targeted product water quality Disinfection strategy

Plant design capacity refers to the proposed instantaneous flow achieved by a given plant design

to achieve the annual produced water flow of 9,000 AFY or 5,500 AFY. The design capacity ofa facility impacts both its construction and operating cost, and must take account of issues suchas equipment redundancy, periodic maintenance, and overall online operating factor.

The issue of product water quality is closely tied to the proposed demineralization systemprocess design of each facility. As discussed previously, DWD and PML have proposed singlepass RO systems; while Cal-Am has proposed a partial (40 percent) second pass system. The twoapproaches will produce different qualities of final product water from an overall salinityperspective, as well as levels of boron and chloride.

In addition to salinity and individual constituent targets, the design must also achieve regulatorypathogen removal thresholds. The California Department of Public Health (CDPH) has primacyto regulate public water systems within the State. As such, they will review these proposedtreatment approaches for compliance with the Surface Water Treatment Rule (SWTR) and theLong Term 2 Enhanced Surface Water Treatment Rule. It is anticipated the slant wells proposedfor the Cal-Am project would be deemed groundwater under the influence of surface water andsubject to the surface water regulations, as would the open intake sources for DWD and PML.

Pathogen removal/inactivation requirements are quantified in increments of influent to effluentconcentration, expressed in a log scale. For example 3-log removal is 99.9%. CDPH willestablish the log removal requirements of a project based on information on the quality of thesource water and other factors. The expected ranges of possible requirements for these projectsare 3-5 for Giardia; 2-4 for cryptosporidium (crypto); 4-6 for virus. Some project proponentshave indicated an expectation the requirements will fall at the low end of the ranges.

Each treatment process is assigned a log removal credit for each pathogen. By summing the

credits of all processes in the multi-barrier approach (filters, RO, disinfection, etc.) a total creditis achieved to meet or exceed the regulatory requirement. Under the disinfection strategydiscussion we consider the removal credits likely achieved by the proposed projects.

PROJECTED PERFORMANCE MONTEREY PENINSULA REGIONAL WATER AUTHORITY


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require cleaning, power outages occur. Without excess treatment capacity or high levels ofcomponent redundancy, annual deliveries could fall short.

Cal-Am has proposed a design capacity basis of 5.4 mgd or 9.0 mgd. These capacities are fairlyclose to what you would get by assuming the treatment plant is on-line and producing water 90percent of the time, which results in capacities of 5.45 mgd and 8.92 mgd. A 90 percent on-linefactor is consistent in our experience of a well-designed and operated municipal RO plant thatdoes not have redundant process units (e.g., RO trains). In Cal-Ams case, they are proposingredundant process units, so its likely the facility will be capable of producing its nameplatecapacity of 5.4 mgd or 9.0 mgd better than 90 percent of the time.

An additional issue specific to Cal-Am however is the potential extraction and return of

groundwater from the SVGB. Cal-Am estimates as much as 8 percent of the plants annualproduction capacity may need to be returned to the basinup to 780 AFY for the 9,000 AFYdemand scenario20. This has the effect of increasing the annual flow requirement to 5,960 AFYor 9,780 AFY; and corresponding minimum plant design capacity to 5.3 mgd or 8.7 mgd.Looked at another way, the plant would need to run at the proposed design capacity roughly 98percent of the time to meet the higher delivery requirement. With the level or redundancy in Cal-Ams design we consider this achievable but not overly conservative.

4.1.2 Targeted Product Water QualityThough Cal-Am has produced a good degree of information to date with regard to their proposedproject, the majority has been in service of supporting their CEQA and CPUC approvalprocesses. They have specifically not developed a target product water quality specification,beyond stating the final product water will meet all State Maximum Contaminant Levels (MCLs)and be non-corrosive. Rational for a partial second pass RO system includes concerns over

levels of boron, chloride and sodium in the final product water as well20

. Also in a presentation,Cal-Am projected treated water TDS from the plant of 380 mg/L and chloride level of 60 mg/Lto blend with existing supplies with a TDS of 440 mg/L and chloride level of 90 mg/L

21.

From their proposed process design and post-treatment strategy we can however model projectedproduct quality independently. In Table 4-1 we have summarized our projection of waterquality produced from a partial two-pass RO process (40 percent blend of second pass product)stabilized with calcite, carbon dioxide and sodium hydroxide.

MONTEREY PENINSULA REGIONAL WATER AUTHORITY PROJECTED PERFORMANCE


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Table 4-1 Summary of Projected Product Quality from Cal-Am Facility


Chloride mg/L 60

Boron mg/L 0.5

pH units 8.0

Calcium mg/L as CaCO3 40

Alkalinity mg/L as CaCO3 40

4.1.3 Disinfection StrategyCal-Am has stated their intent for their pathogen removal credits to comply with the Surface

Water Treatment Rule (SWTR) and achieve 4 log removal of giardia and 6 log removal of virus.This would be accomplished through a multi-barrier treatment approach including their intakewells, pretreatment filters, RO process, chlorine disinfection, and (if required) UV disinfection.

Our evaluation of the proposed Cal-Am process in terms of specific pathogen credits is presentedin Table 4-2. The ability of Cal-Ams slant-wells to receive aquifer (bank) filtration credit isuncertain (dependent on design and local conditions) and the inclusion of UV disinfection istentative, totals were calculated with and without those values.

Table 4-2 Summary of Projected Pathogen Credits for Cal-Am Project

CDPH Requirement (Potential Range) 3-5 2-4 4-6

Aquifer Filtration 1 1 -

Granular Media Filtration 2.5 2 2

RO 2 2 2

UV 2 2



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4.2.1 Plant Design CapacityThe original DWD response to the TAC included proposed demand conditions of 25,000 AFYand 10,700 AFY, with plant capacities of 22.3 mgd and 9.1 mgd. In response to questions fromSPI, DWD proposed to meet the 9,000 AFY condition with their original 9.1 mgd plant capacity,and the 5,500 AFY condition with a plant rated at 4.9 mgd.

Using the same performance metrics discussed above for Cal-Am, the DWD facility would needto operate at an online factor of roughly 100 percent for the 5,500 AFY demand condition; and88 percent for the 9,000 AFY scenario. Its unclear why DWD used varying assumptions for

each condition, but could be a consequence of their larger, regional facility approach and anassumption that the 5,500 AFY supply would be served as a portion of a larger capacitytreatment plant.

Like Cal-Am, DWD includes sufficient redundancy in their proposed treatment systemequipment to justify a greater than 90 percent online factor. On an equivalent basis with Cal-Am, a 98 percent online factor would result in plant capacities of and 5.0 mgd and 8.2 mgd,respectively.

4.2.2 Targeted Product Water QualityIn their response to questions from SPI, DWD provided their target product water quality whichis reproduced in Table 4-3. In general, DWD proposes to provide a product supply that iscompliant with all applicable drinking water regulations, is non-corrosive, and compatible withexisting supplies in the Cal-Am distribution system.

Table 4-3 Summary of Projected Product Quality from DWD Facility

Total Dissolved Solids mg/L


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4.2.3 Disinfection StrategyDWD will achieve required disinfection and pathogen removal credits though media filtration,

RO, and chlorine disinfection. We project the overall process to achieve overall requirements assummarized in Table 4-4.

Table 4-4 - Summary of Projected Pathogen Credits for DWD Project



RO 2 2 2

Chlorination 0.5 2+

4.3.1 Plant Design CapacityThe PML response to the TAC included proposed demand conditions of 5,500 AFY and 10,700AFY, with plant capacities of 4.8 mgd and 9.4 mgd. In response to questions from SPI, PMLproposed new capacity increments of 5,000 AFY and 10,000 AFY. Corresponding production

capacities were not provided, though a narrative equipment list with design operating flux andmembrane area and element assumptions were provided for each scenario. From thisinformation, we calculated a plant design capacities of 4.5 mgd and 9.0 mgdroughlyequivalent to producing 5,000 AFY or 10,000 AFY if operated continuously (100 percent onlinefactor). Actual target delivery scenarios for the peninsula are 5,500 AFY and 9,000 AFY.

From the equipment information provided it does not appear that any excess membrane area isproposed that would indicate the presence of redundant equipment. With this approach, a lowerassumption of achievable plant online factor would be recommended. However, we do not

consider the approach good design practice and find it at odds with proposed systems from theother candidate proponents. We have therefore evaluated the PML system in our analysis ofhaving redundant process units and therefore an equivalent system design capacity to DWD ofeither 5.0 mgd or 8.2 mgd.



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Table 4-5 Summary of Projected Product Quality from PML Facility1


Chloride mg/L 131

Boron mg/L 0.6

pH units 6.6

Calcium mg/L 1

Alkalinity, as CaCO3 mg/L 1

1Listed quality is projected permeate from the RO system, prior to final stabilization and pH adjustment.

4.3.3

Disinfection StrategyWith their currently proposed pretreatment strategy, sufficient log removal credits for giardia,crypto and virus should be achievable. One unknown however is the level of organics that maybe present in the harbor-extracted supply; and the potential to create disinfection byproducts.This issue should be explored in the planned pilot test program, which will also be used tofinalize the proposed process design and disinfection strategy. Our evaluation results arepresented in Table 4-6.

Table 4-6 - Summary of Projected Pathogen Credits for PML Project



MF/UF 4 4 2

RO 2 2 2

Chlorination 0.5 2+

MONTEREY PENINSULA REGIONAL WATER AUTHORITY ECONOMICS


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In our original project scoping technical memorandum2 we recommended the following criteriato evaluate the candidate projects on an equivalent basis:

Uniformity in plant design capacity for the two non-regional approaches; equivalentcapacity allocation for the proposed DWD regional project.

Equivalency in treatment to achieve: a common RO feed water quality followingpretreatment; a common treated water quality goal; and pathogen removal credits

required for the applicable supply source.

Uniformity in equipment redundancy. Uniformity in unit cost criteria for common items. Uniformity in cost factors applied to aggregated costs (e.g., contingencies; electrical

and I&C costs; etc.).

Uniformity in unit costs for chemicals and other consumables for treatmentevaluations.

We accomplished implementing the above principles in large measure in our economicevaluation. We adjusted plant capacities for the evaluation on the basis described in Section 4,rating Cal-Ams proposed system at design capacities of 5.4 mgd and 9.0 mgd; and the DWDand PML systems at 5.0 mgd and 8.2 mgd. In terms of treatment process, we attempted tomaintain the overall proposed process design of the proponents, but did evaluate all as includinga partial (40 percent) capacity second pass RO system. We also assumed N+1 redundancy on all

rotating equipment and major treatment process units (e.g., filters, RO membrane trains). Weemployed an equivalent basis in developing our capital equipment cost estimates, relying ontargeted quotes for equipment and SPIs cost information from past, similar seawater RO projects.For indirect costs, we assumed fixed factors and applied them uniformly to each project. Eachfactor, expressed as a percentage, was applied to estimated plant construction cost, absent costsassociated with off-site trenched pipelines. These factors included the following:

1. Implementation Costs at 25 percent, to include items such as permitting, pre-constructiondesign services, procurement development, and compliance activities.

2. Mobilization/Demobilization costs at 2 percent to account for supply and removal ofcontractor equipment to the facility during construction.

3. Electrical and I&C Systems cost at 18 percent, accounting primarily for post-serviceswitchgear motor control centers drives conduits wire and SCADA systems

ECONOMICS MON

mprwa evaluation of seawater desalination projects final report december 2012

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