Water’s getting scarcer, and the lack of rainfall in some areas is prompting people to use resources they might have resisted even a short time ago.
The use of recycled graywater—technically called “direct potable reuse,” but often labeled “toilet to tap,” which doesn’t help public acceptance at all—is becoming more common. For some communities, such as El Paso, TX, it’s a fairly new source of water. As this article points out, the city historically has drawn about half its water supply from the Rio Grande, but a chain of events—including less snowpack in New Mexico and Colorado and thus less water in the river—has led the city to look for other sources. Pumping more water from the already-depleted aquifer is not a permanent solution.
El Paso is now building a facility to purify treated water from the sanitary sewer system. Unlike indirect potable reuse, which might send the treated water into an aquifer or basin to be pumped out perhaps years later, this facility will treat the water in a series of steps, including UV and carbon filtration, and then send it into the drinking water pipelines. As the article notes, by 2030 desalination should be providing about 10% of El Paso’s water, while another 6% will of come from this type of advanced purification.
Other cities have been recycling sewage for decades. This article covers the 20th anniversary of a treatment plant in Scottsdale, AZ, that can purify raw sewage in about 12 hours. Unlike in El Paso, though, the treated water is used to recharge an aquifer.
Water Efficiency’s editor, Laura Sanchez, explores various water reuse options in this blog post, including public attitudes and acceptance of different methods.