AWWA ACE63132

The primary source of drinking water for the San Antonio metropolitan area is the Edwards Aquifer. Since this aquifer is under increasing pumping restrictions and the San Antonio area is experiencing tremendous growth, the San Antonio Water Systems (SAWS) is looking for ways to supplement and diversify its water resources. One of these efforts is a recycled water program. By utilizing this non-potable water for use in irrigation, commercial and industrial applications, SAWS has been able to reserve more Edwards water for potable uses. Commercial and industrial HVAC cooling towers were identified as potential users of recycled water (RW). Open recirculating evaporative cooling towers use large amounts of water to dissipate heat generated by a number of different processes. The use of recycle water in cooling towers has resulted in a substantial amount of potable water savings. One of these prospects included a 15,000 ton chilled water facility that uses 90 million gallons of make-up water. This facility is operated by SAWS and supplies chilled water to much of downtown San Antonio including the Convention Center. This facility was converted to recycled water in 2003 and SAWS staff has been very satisfied with the results. There has been no indication of increased corrosion, microbiological problems, scaling, or an increase in treatment costs. Many other facilities have converted their cooling towers to RW including two hospitals, three military bases, several dormitories, an office complex, and a major manufacturing facility.