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Issue link: http://wateronline.epubxp.com/i/367462
Feature wateronline.com ■ Water Online The Magazine 8 W hen John Grant and his team in Big Spring, TX, initially decided to build the first-ever direct potable reuse (DPR) facility in the U.S., they weren't trying to make history. In fact, Grant, the general manager for the Colorado River Municipal Water District (CRMWD), wasn't even aware that there are only a handful of facilities worldwide that utilize DPR — the process of reusing treated wastewater as drinking water without an environmental buffer. The CRMWD was simply looking to provide clean, safe water for the district's consumers in Odessa, Big Spring, Snyder, and Midland during the region's worst drought in decades. "When we started our project back in 2002, we didn't even intend for it to be a DPR project. We were just looking for new water supplies in our area," said Grant. "We weren't able to build any more surface reservoirs because we physically had no more room, most of the fresh ground water had already been developed, and indirect potable reuse (IPR) wasn't an option because we get more than 60 inches a year of evaporation." It took over a decade to research, test, and determine an alternative, but by May 2013 the CRMWD opened a DPR plant — which can treat up to 2 million gallons of wastewa- ter effluent per day to drinking water standards. The plant immediately gained national attention, and another Texas town took note. By June 2014, Wichita Falls — located 230 miles away from Big Spring — opened the second U.S. DPR plant, which can treat up to 10 million gal- lons of wastewater effluent per day. The Treatment Process While both Wichita Falls and Big Spring use the DPR pro- cess, each plant's methods vary slightly. The Big Spring plant treats the wastewater effluent at a new $14 million facility using microfiltration, reverse osmosis (RO), and ultraviolet disinfection (UV). That water is then added to a raw water pipeline that also sources water from an area lake. This mix (20 percent recycled water, 80 percent raw water) is then distributed to five drinking water facilities in the region (serving a total of about 250,000 people), where it is treated again using conventional drinking water treatment techniques. Implementing DPR did not require much additional technical knowledge. "This technology is not rocket science," said Grant. "This is all technology we already knew how to use." In Wichita Falls, there was no need to build a new plant just for DPR. This is because one of the region's lakes is brackish, and so a microfiltration and RO plant already existed to treat that source water. All that was needed for DPR was a 13-mile aboveground pipeline to connect the wastewater treatment facility to the drinking water plant. The pipeline cost around $13 million. Like Big Spring, Wichita Falls mixes its treated effluent with raw water. Their mix is 50-50 and takes place at the same facility where it is treated again using conventional drinking water treatment techniques. The end result is distributed to roughly 150,000 people. The long-term goals of each facility also differ. While the Big Spring plant is considered a pilot project with plans to expand, the Wichita Falls facility is only a temporary solution. There are plans to transition Wichita Falls to an IPR facility (wastewater recycling using an environmental buffer) in the next two to four years depending on drought conditions. DPR was chosen as the first stage because the utility already had most of the technology in place. The aboveground pipeline created for DPR has been sized for IPR flow into a lake and will save the Texas Leads The Way With First Direct Potable Reuse Facilities In U.S. By Laura Martin, associate editor, Water Online Severe drought prompts both Big Spring and Wichita Falls to recycle wastewater effluent for drinking water use. Will others follow suit? Reverse osmosis equipment is used to disinfect the recycled water at the Big Springs DPR plant.