Desalination and water reuse in updated San Antonio plan
The city of San Antonio in Texas, USA, has identified desalination and water reuse as major components of its updated water management plan, launched on 4 November 2009.San Antonio Water Systems' (SAWS) new plan identifies a permitted supply gap of 141,000 acre-feet (174 million m³) in the worst year of a repeat of the drought of record up to 2060. SAWS has outlined short-range (up to 2014), mid-range (2015-2034) and long-range (2035-2060) strategies to deal with this shortfall.
In the short-range program is Phase 1 of the Brackish Groundwater Desalination (BGD) project and an ocean desalination feasibility study.
For the BGD project, a wellfield will be developed in southern Bexar County in the Wilcox Aquifer. The treatment plant will be located on SAWS' Aquifer Storage & Recovery property and will initially treat 11,800 acre-feet (14.5 million m³) per year. The treatment plant will be designed to accommodate additional upgrades and technologies.
In the future, once the science of desalination has been proved to concerned citizens, production may be added in Wilson and Atascosa counties to expand the supply, treatment and use of brackish groundwater from those sources. Possible brine injection locations to be considered include southern Bexar and/or Wilson counties.
SAWS will begin a feasibility study to identify potential sites for ocean desalination, pipeline routes, permitting requirements, construction challenges, and partnership opportunities. Though the plan describes ocean desalination as the most expensive proposed source of new water resources, it says, "serious study will provide some certainty and firmness to cost estimates for more informed consideration in future Water Management Plans".
The mid-term program, which has to address an additional 47,538 acre-feet (58.6 million m³) of permitted supply shortfall, has expansion of the BGD project as one option and new recirculation and recharge options to be investigated.
In the long term, for which an extra 75,600 acre-feet (93.3 million m³) will have to be found in addition to the two previous upgrades, construction and delivery of an ocean desalination project would be anticipated.
SAWS says it will remain a national leader in the utilization of recycled water to maximize limited resources for potable uses.
"Recycled water has become a factor in economic growth and development in an age of increased awareness of issues involving environmental stewardship," says the new management plan. "The use of recycled water for non-potable uses has been a fundamental component of SAWS' water resources management and conservation efforts."