WSP07913

• File Number: 8277.400.200
• Description: Lower Virgin River Project
• State: NV
• Basin: Colorado Mainstem
• Date: 11/1/1986
• Title: Study of Saline Water Use at the Harry Allen Generating Station - Final Report - November 1986
• Water Supply Pro - Doc Type: Report/Study

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Section 4

SELECTION AND DESIGN OF WATER TREATMENT PROCESS OPTIONS

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The objective of this activity was to select water/wastewater treatment
process options to be used as a basis for technical and economic comparison of
the secondary sewage effluent and Lower Virgin River Unit sources at the Harry
Allen Station. The base case for comparison Is the water system design con-
tained in the "Comparative Study of IGCC & PCF Technologies" study prepared by
the Bechtel Power Corporation, which uses secondary sewage effluent as the
station makeup source.

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This activity Included a review of commercially available and emerging saline
water use technologies, and the design and screening of water treatment
process options.

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SALINE WATER USE TECHNOLOGY REVIEW

Saline water use technologies applicable to raw water treatment, wastewater
treatment and final wastewater disposal were selected from power Industry ex-
periences. Emerging technologies with potential cost savings were Identified.

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The technologies selected for review Included the following:

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Ion exchange softening
Lime/soda softening
Circulating Water Chemical Treatment
Reverse Osmosis
Electrodialysis
Vapor compression evaporators
Evaporation ponds

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Ion ExchangA SoftAnlng

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Ion exchange softening applied to power plant saline water use Is an emerging
application which has been tested In the Firebaugh Project and Is under test
at the California Department of Water Resources Los Banos facility and at the
Etlwanda Power Plant In California.

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The Bureau of Reclamation sponsored and directed field testing of Ion exchange
prior to reverse osmosis and electrodialysis desalting at sites near Yuma,
Arlzona.and LaVerkln Springs, Utah. The feedwater at the Yuma site had a TDS
level near 3,000 mg/I. The test unit was successfully regenerated with all
waste brine concentrations tested, which ranged from 20,000 to 50,000 mg/I
TDS. The LaVerkln Springs test unit achieved performance equal ling that ob-
tainable with conventional sodium chloride regeneration. This was attributed
to the essentially unlimited volume of brine available and regeneration of the
resin through multiple recyl Ing of the regenerant.

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The Firebaugh test was sponsored by the California Department of Water
Resources (DWR), Southern California Edison Company (SeE), Pacific Gas and

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