WSP07460

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 2/1/1963
• Author: USDOI/BOR
• Title: Special Studies - Delivery of Water to Mexico
• Water Supply Pro - Doc Type: Publication

Chapter IV

Cost of Desalted Water and the YDP Cost
Reduction Program

Cost of Desalted Water

YDP product water is expected to have a
total cost of about $699 per acre-foot. If
about 10,000 acre-feet of untreated
irrigation drainage is blended with the
product water and discharged to the river
for delivery to Mexico, the cost of the total
water recovered is about $610 per acre-foot,
These costs are based on full-capacity
operation, a 50-year amortization period,
and an interest rate of 5-5/8 percent, (See
table 3.)

Industry-wide, typical total desalting costs
(capital cost plus operation and main-
tenance costs) range from about $1.00 to
about $2,50 per 1,000 gallons, or $325 to
$812 per acre-foot, 1 The amortization
period and interest rate used are not
available,

In 1988, The Metr!lPolitan Water District of
Southern California (MWD) prepared a
report on the cost of desalting water
utilizing available technology,2 The report
documented desalting costs at 22 de-
salination plants:

. Ten plants used reverse osmosis to treat
brackish ground water.

. Four plants used reverse osmosis to
demineralize municipal secondary effiuent
and agricultural drainage water.

. Three plants used electrodialysis to treat
surface and ground water.

. Five plants used reverse osmosis or
multiple-effect thermal distillation to
desalt seawater,

Total desalting costs for these plants were
developed and compared. Unit costs for
plant construction were based on a 20-year
amortization period and an interest rate of
8-7/8 percent (the prevailing United States
Treasury Department rate for July 1987),
All operating and maintenance costs reflect
actual 1986-87 data. According to the
results, the cost of desalting brackish water
in southern California ranges from $350 to
$2,250 per acre-foot, These costs vary
considerably site-to-site and depend on the
size of the facility and specific pretreatment
requirements, The report recommends that
MWD use a range of $350 to $750 per
acre-foot for general cost estimating,

Assuming full-capacity operation and
applying the same amortization period and
interest rate used in the MWD report, YDP
desalted water costs $886 per acre-foot to
produce, The recovery of irrigation

1 Journal AWWA. Committee Report: Membrane Desalting Technologies, AWWA Water Desalting and Reuse
Committes, September 1989, psge 37,
:I. Assessment of Desalination Tl!Chnology, Prepared for Mstropolitan Water District of Southern California, by
Black and Veatch Engineen-Architects, Report No. 993, August 1988.

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