SUSTAINABLE RESOURCE MANAGEMENT in San Antonio
By Gregg Eckhardt
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Aerial photo of the Dos Rios Water Recycling Center.
As Texans are prone to brag, the Dos Rios staff will boast that it is the greenest place in Texas.
Reusing water was the easy part. When faced with supply limitations from its primary water source in the 1990s due to endangered species concerns, SAWS built the nation’s largest direct recycled water system with a capacity of 35,000 acre-feet per year. More than 130 miles of large diameter pipelines deliver tertiary-treated water that is almost drinking-water quality to irrigators, industrial customers like a Toyota truck plant, Microsoft, and the historic Alamo. The $140 million system is dual use in that water is also delivered to remote outfalls on creeks and rivers for environmental flow maintenance. San Antonio’s world-famous River Walk had previously been supplied with water from potable wells; today, the flow is almost entirely recycled water, thereby saving drinking water for potable uses. Another outfall on Salado Creek resulted in the removal of the creek from the federal list of impaired water bodies for dissolved oxygen, and it laid the foundation for large public investments in linear parks that today are a MUNICIPAL WATER LEADER
PHOTOS COURTESY OF SAN ANTONIO WATER SYSTEM.
t the spot where water from the San Antonio Water System’s (SAWS) Dos Rios Water Recycling Center cascades 50 feet down into the river, a visitor from a group of international guests gently wept. When asked if everything was alright, he nodded. “I’m ok,” the visitor said. “It’s just that in my country, we don't even have water like this to drink. And here you can just send it into the river.” The group had come because they heard that Dos Rios, SAWS’s largest water recycling center, is the place to learn about sustainable resource management in wastewater. As Texans are prone to brag, the Dos Rios staff will boast that it is the greenest place in Texas. Back in the 1990s, SAWS began viewing all treatment process residuals as valuable resources, not waste products. Those residuals include 140,000 acre-feet of recycled water per year, 165,000 tons of biosolids, and 1.5 million cubic feet per day of methane-rich digester gas. In 1996, the staff hatched a bold plan to try to reuse everything, putting nothing to waste. The catch was that any project they pursued had to be environmentally friendly while either saving money, being cost neutral, or producing a revenue stream. If projects had side benefits like water conservation, that would be factored into a cost-benefit analysis. The effort, led by SAWS Chief Operating Officer Steve Clouse, took almost 20 years to accomplish, but it demonstrated that being green and fiscally responsible are not mutually exclusive. In fact, they are complementary goals. And so visitors come from all over the world to Dos Rios to see what SAWS did and how they did it.
