Operation of SAWS New Groundwater Desal Plant - Richard Donat

TWCA

Richard DonatExecutive Management Analyst, Engineering and Construction

San Antonio Water SystemBrackish Groundwater Desalination Project

March 1, 2017

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Outline• Water Challenges • Project Background• Project Challenges• Facility Highlights

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Water Supply Challenges

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Why Brackish Inland Desalination

• Large volumes of available brackish water

• Resource close to San Antonio

• Identified in the SAWS 2005 Water Management Plan

• Diversification• Untapped resource

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Desalination Program

• Phase I (2016) – 12 MGD – 13,440 Acre-feet / year– (~53,000 Households)

• Source Water– Lower Wilcox Formation– 12 Production wells (~1,500’ avg. depth)

• Treatment Process– Reverse Osmosis

• Concentrate Disposal– 2 Injection wells (5,000’ avg. depth)

General Information

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Project Cost

• Project Cost: $192.7 million, $1,177 $/AF• Began producing water November 9, 2016

Phase I

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Challenges• State and Local Groundwater

Regulation• Public Perception• Stakeholder Buy in• Funding/Value Engineering• Real Estate• Concentrate Disposal• Design • Construction • Operational

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Concentrate DisposalOptions Considered

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Design

• Prevent Membrane fouling – Open System vs. Closed

System– Pre-treatment

• Finish water quality standards

• Short design timeline– Multiple sub-consultants

Challenges

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Construction Challenges

• Budget– Managing a budget

without owner contingency

• Schedule– Record Rainfall (2 yrs.)

• Complicated Construction– 13 Work Packages

Challenges

$

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Operational

• Learning curve – Fully automated plant– Bring in operators early– 1 month RDT & 3 months

commissioning phase• Operational– Raw Water

• Cartridge Filters/Turbidity– Fouling– Meeting Finished Water Goals

Challenges

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Stage 1

Stage 2

Reverse Osmosis Primary Trains

Stage 1

Stage 2

Stage 1

Stage 2

Stage 1

Stage 2

Lower Wilcox Wellfield

Pre-Filters

13.11 mgd

2 mgd

Anti-Scalant

Reverse Osmosis

Concentrator Trains

Stage 3

Stage 3

8.88 mgd 1.11 mgd

Injection Wells

12 mgd

1.11 mgd

H2SO4

Calcite Contactors

30%

70%

CO2

Degasifiers

NaOH Cl2

Process DiagramOperational

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Construction 2014 to PresentBuilding Success

June 2014 April 2015

December 2016February 2016

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Treatment Facility

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Three Water Supplies at H2Oaks

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Water Supply and Educational CenterEducation and Outreach

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Water Supply and Educational CenterEducation and Outreach

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Grand Opening FestivitiesJanuary 27, 2017

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Thank you

TWCA

Richard DonatExecutive Management Analyst, Engineering and Construction

San Antonio Water SystemBrackish Groundwater Desalination Project

March 1, 2017

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Regulatory

• State and Local Groundwater Regulation– 16 Groundwater

Management Areas– 100 Groundwater Districts

• Challenges:– Desired Future Conditions

(DFCs)– Groundwater Permits

Challenges

http://www.tceq.state.tx.us/assets/public/permitting/watersupply/groundwater/maps/gcdmap.pdf

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Stakeholder Buy in

• Large project many different stakeholders across SAWS

• Partnering sessions with SAWS upper management

• Desal plant visits across the United States

• Outreach to San Antonio elected officials and SAWS Board of Trustees– Addressed Project concerns

• Construction Manager, Program Manager, and SAWS Workshops

Challenges

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BudgetingDeveloping Cost Estimates

*For comparison purposes all estimates assume 5% annual debt service*2009/2010 Estimate 10 MGD / 2012 Estimate 10.9 MGD / 2014 Estimate 12 MGD

• Economy• Increase Plant

Capacity• Scope/Vision

Change• New

Information• Estimates vs.

Actual Bids

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Funding

• Rate approval through SAWS board of Trustees and City Council

• Texas Water Development Board (TWDB) Low Interest Loans

• Construction estimates greater than budget estimates– Value Engineering– $17.7M reduction

Funding Sources for the ProgramInterest

Rate$/acre-

foot$/1,000 gallons

5% $1,370 $4.20 4% $1,266 $3.89 3% $1,177 $3.60

*Without and interest rate reduction SAWS would need to lower the capital cost by $40M to achieve $1,177 / acre-foot

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Real Estate

• Purchasing land needed for well field– 3,200 acres already owned– Additional 2,800 acres

purchased – Takes time• Land is leased back for

agriculture and grazing– Livestock

• Working with neighbors– Public Meeting

Challenges