Using Recycled Edwards Water

Use of recycled water from wastewater treatment plants could take a great deal of pressure off the Edwards Aquifer resource.  There are plenty of uses such as air conditioning cooling towers and golf course irrigation that do not require potable Edwards water.  Treated wastewater contains small amounts of nutrients, so in the case of irrigation using recycled water can actually be a benefit and reduce fertilizer costs.

San Antonio rarely gets much credit for having pioneered an innovative use of wastewater effluent decades ago.  Braunig Lake, first filled in 1963, was the first attempt to use wastewater effluent discharged from treatment plants for cooling electrical power plants.  Initially there were some problems with algae and suds from high-phosphate detergents, but the scheme ended up working so well that Calaveras Lake was built in 1968.  Braunig Lake covers 1,350 acres, and Calaveras Lake covers 3,550.  About 20,000 acre feet of cooling water is consumed that would otherwise have to be drawn from potable supplies.

Mitchell Lake is not a cooling lake - it served as a huge oxidation pond into which San Antonio's raw sewage flowed until treatment plants were built in this century.

 City Public Service Cooling Lakes

CPS pump station on the San Antonio River  
These monster pumps on the San Antonio River have a combined capacity of about 98 million gallons per day.  That is about equal to the combined discharge of all of San Antonio's water recycling plants on a very dry, low-flow day.

View of San Antonio River from pump station
Flow in the San Antonio River can be greatly reduced past this point when the pumps are running.
Braunig Lake
Braunig Lake covers 1,350 acres in south Bexar county. The power plant across the lake uses wastewater effluent for cooling.

 

Aside from the cooling lakes, there traditionally has been very little reuse of Edwards Aquifer water.  In 1997 the San Antonio Water System started construction on a massive distribution system to move treated wastewater to locations where it can be beneficially used.  Eventually water supplied for non-potable uses by this system will supply up to 35,000 acre-feet per year, about 20% of the volume that San Antonio currently withdraws from the Aquifer.

SAWS Recycled Water Distribution System

 

SAWS' project also involves augmenting the flow of the San Antonio River in the downtown area with recycled water so that Edwards wells supplying flow to the River Walk can be shut off.  The first discharge of recycled water occurred on March 28, 2000 near the inlet to the river flood tunnel, and it marked a historic and momentous day for the City.  On June 20 dignitaries celebrated the completion of a second discharge location in Brackenridge Park by heaving buckets of recycled water into the river (left).  Just moments before, the Edwards well in the left foreground was shut off.  For decades, this well and two others supplied the entire dry-weather flow of the San Antonio river in the River Walk area.  For more on how this water is produced, see the section on Water Recycling.

The San Antonio River Authority and the city of Converse are also getting involved in using recycled water. SARA owns and operates several small wastewater treatment plants, and one of them that serves Converse, Live Oak, and Universal City is very close to Judson High School. It discharges about 3.5 million gallons per day into Salatrillo Creek. For only about $50,000 a pipeline and pump station can be installed to supply recycled water to the high school's athletic fields. They currently use about 1 million gallons of Aquifer water per month during the summer. In September 2000 the city of Converse received a permit from the TNRCC to pump up to 796 acre-feet per year of recycled water from Salatrillo Creek, and money to construct pipelines and pump stations has already been set aside.


 
Water Use at Fiesta Texas Theme Park 
Uses such as this are prime targets for reuse and recycling projects.  Though quite aesthetically pleasing, there is really no reason that potable Edwards water has to be used.  However, since Fiesta Texas is situated over the recharge zone, and since there are pervasive negative public attitudes about moving recycled water to this area, it is not currently planned that the SAWS Recycled Water System will reach Fiesta Texas.  It is likely that all of the recycled water available can be used before it is pumped this far north anyway.

Water Use at Fiesta Texas Theme Park
Another view of water use at Fiesta Texas Theme Park taken shortly after the Park opened in 1992.