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Description:
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As the U .S . population continues to increase , planning for future water quantity and
quality needs is important . Historically , many municipalities have relied heavily on
surface water as their major source of drinking water , but recently , technological
advancements have improved the economic viability of reverse -osmosis (RO )
desalination of brackish -groundwater as a potable water source . Brackish -groundwater
may be an alternative water source that provides municipalities an opportunity to hedge
against droughts , political shortfalls , and protection from potential surface -water
contamination . This research specifically focuses on investigating economies of size for
conventional surface -water treatment and brackish -groundwater desalination by using
results from four water treatment facilities in the Texas Lower Rio Grande Valley
(LRGV ) . The methodology and results can have direct implications on future water
planning . Economic and financial life -cycle costs were estimated for a "small" -
conventional -surface water facility (2 .0 million gallons per day (mgd ) Olmito facility )
and a "small" -brackish -groundwater desalination facility (1 .13 mgd La Sara facility ) .
Prior analyses were modified to determine similar costs for a "medium" -sized
conventional surface -water facility (8 .25 mgd McAllen Northwest facility ) and a
"medium" -sized brackish -groundwater desalination facility (7 .5 mgd Southmost facility ) .
The life -cycle costs of the "small" Olmito facility are compared to the life -cycle costs of
the "medium" Northwest facility and the life -cycle costs of the "small" La Sara facility
are compared against the life -cycle costs of the "medium" Southmost facility to
determine the existence of economies of size .
This research was facilitated by the use of the CITY H20 ECONOMICS© and the
DESAL ECONOMICS© Excel® spreadsheet models previously developed by Texas
AgriLife Research and Texas AgriLife Extension Service agricultural economists .
Although the results are applicable to the Texas LRGV , economies of size are apparent
in conventional surface -water treatment and constant economies of size are evident in
brackish -groundwater desalination . This research also concludes that RO desalination of
brackish -groundwater is economically competitive with conventional surface -water
treatment in this region . |