WATTS Conference- Desalination Plant Project

BW Primoris(Gaines County Water Company)

Water Supply and Treatment SystemSeminole, TX

Primoris Services Corporation

3/22/2016

• Provides construction, fabrication, maintenance, and product engineering services for public utilities, energy companies, municipalities, and others.

• Publicly traded – PRIM • $2 billion/year of revenues• BW Primoris is the PSC subsidiary that partners with

municipal and industrial customers, addressing their water needs by providing services to advance their water projects

• Definition and development• Construction• Financing and ownership• Operations

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Seminole, TX Project

Services provided:• Increase water supply; reduce TDS, As, and F in drinking water

Infrastructure installed to date:

• Design, build, own, and operate three reverse osmosis plants

• Design, build, own, and City operates 2 new wells

Status:

• Full operations started January 1, 2016

Service Commitment:

• 40 years

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Seminole Water Supply System

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Osmosis

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A solution that is less concentrated has a natural tendency to migrate to a solution with a higher concentration, thus weakening it.

Reverse Osmosis (RO)

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In RO, pressure is applied to cause water to move the other direction.

3/22/2016 7From ESP Water Products

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Reverse Osmosis Plant Tour

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Challenges affecting the system

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• Silt Density Index (SDI)• The silt density index is a measure for the fouling capacity of water in

reverse osmosis systems. • The guideline is to maintain SDI at less than or equal to 5. • Multi-media filtration followed by microfiltration is provided to help

keep the SDI below 5. SDI is measured daily. • Silica (silicon dioxide or SiO2)

• A hard, glassy mineral substance which occurs in a variety of forms such as sand, quartz, sandstone, and granite.

• As water moves through soil and rock, silica is picked up by the water.• Silica can readily foul RO membranes. It can also collect in the RO

concentrate stream and exceed saturation.• Preventative measures

• pH adjustment• Anti-scalant

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New Groundwater Wells

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Improvements to System

3/22/2016

• RO concentrate management alternatives• Arsenic removal via filtration without RO• Additional raw water supply

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For more information . . .

3/22/2016

Scott AhlstromBW Primoris2100 McKinney Ave, Suite 1500Dallas, TX 75201

214-740-5614sahlstrom@prim.com

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