In January, San Antonio Water System (SAWS) introduced a new drinking water source to the Texas city — desalination — which it deemed a drought-resistant source and a huge leap forward in water independence. The SAWS project pumps brackish water from about 1,500 feet deep in the Wilcox Aquifer under south Bexar County as the source for this purified drinking water. Reverse osmosis removes 97 percent of the salts and minerals in the water, producing 12 million gallons per day, enough water to supply 53,000 households.
According to SAWS, every 10 gallons of brackish water is converted to 9 gallons of drinking water. Injection wells more than a mile deep are used to dispose of the concentrate/brine.
“Desalination is another tool in our water portfolio that we are using to serve a growing San Antonio,” said SAWS CEO and President Robert R. Puente. “There is an ocean of brackish water under our feet unaffected by drought.”
The desalination plant, located at the H2Oaks Center in southern Bexar County, includes 12 production wells and two injection wells, in addition to a water testing laboratory and treatment processing area. The center also functions as an educational facility, featuring a tour layout for educational opportunities and an onsite research facility available for universities. The plant was also designed to allow for easy expansion in the future.
H2Oaks Center is the only location in the country where three sources of water are produced. It desalinates water, pumps and treats Carrizo Aquifer water, and stores Edwards Aquifer water in the Aquifer Storage and Recovery (ASR) site on the property (see Figure 1)
“This is another step in the right direction toward adding new supplies for San Antonio’s future,” said SAWS Board Chairman Berto Guerra, Jr. “We have the benefit of the 12 million gallons per day, and can access additional phases of desalination as we need them.”
SAWS, which provides water and wastewater services to more than 1.6 million consumers in the San Antonio region, operates the largest direct recycled system in the country, the largest groundwater-based ASR facility in the nation, and was the first in the U.S. in converting methane gas to energy.
Information provided by the San Antonio Water System (www.saws.org).