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TWCA
Richard DonatExecutive Management Analyst, Engineering and Construction
San Antonio Water SystemBrackish Groundwater Desalination Project
March 1, 2017
March 1, 2017
SAWS Brackish Groundwater Desalination ProjectPage 2
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
March 1, 2017
SAWS Brackish Groundwater Desalination ProjectPage 21
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
