Wichita considers treating sewer water for use as drinking water in future
06/08/2014 6:21 AM
08/06/2014 10:56 AM
Turning sewer water into drinking water may be the future of Wichita’s water supply, city officials said this week.
The concept of reusing treated wastewater for everything from drinking to golf course irrigation is one option as officials launch a spring search for water to supply the city in the next 50 years.
The city is examining several methods for turning wastewater into drinking, industrial and irrigation water, Public Works Director Alan King said.
Officials at the Kansas Department of Health and Environment are finalizing wastewater-to-drinking-water treatment regulations modeled after those in place in California, King said.
City public works officials and outside consultants are studying the 50-year water future of the city, with a report expected this spring.
The concept of turning wastewater into drinking water first surfaced last summer during drought deliberations and has been re-energized by the study. Among other options is buying and piping water from El Dorado.
King said the city is most interested in “indirect potable water reuse” – essentially putting wastewater into the Arkansas River and then reclaiming it downstream from storage wells for treatment, in essence allowing nature to filter the impurities as the water moves down the river.
Council member James Clendenin said he’s excited about the possibilities of reusing water for a range of purposes, including drinking.
“That’s what I’m focusing my energies on – the water we drop into the Arkansas River that others are taking out of the river and using for themselves, cities like Arkansas City, the Kaw Lake in northern Oklahoma that provides a number of water users.
“Why are we not using the discharge water from the wastewater facility, and that’s 30 million gallons on the low end? To me, that’s 30 million gallons a day we’d have available to us.”
City officials underscore that they have not decided yet to proceed with turning wastewater into drinking water.
Arkansas City officials, who have between 3 million and 5 million gallons of wastewater discharge daily, have essentially stepped back from a major reuse program because of costs, city manager Nick Hernandez said.
Public perception was another factor, he said. The notion of drinking or using sewer water is a tough sell.
“We’d actually have to put in a giant wetlands that would serve as a pre-treatment of sorts to eliminate biological concerns,” he said. “You’d have to have a very large acreage to build a giant wetland so the particles in the water can be absorbed by the plants and soil below it.”
Arkansas City never considered converting wastewater into drinking water, Hernandez said, because state health officials advised against it several years ago.
“The best use you have for that water is to re-utilize it for irrigation, for reflushing toilets, a lot of different applications. You just can’t use it for drinking and cooking,” he said.
Some cities, such as San Diego, already use treated wastewater for drinking.
Right now, city officials don’t know what it would cost to put the wastewater back into circulation.
“Water resources themselves are very expensive,” said Ben Nelson, the city’s special services manager in public works. “Once we have a draft of the resources report finalized for the council, we’ll have some specific costs.”
Clendenin thinks that improvements already underway at Plant 2, 57th and Hydraulic, could pave the way for an enhanced water reuse operation.
“If we’re spending the money we are already to meet EPA requirements and treat water more, then why don’t we spend the money on diverting all of this water from the river and making it usable?” he said.
“The technology is there, and the water we’re dumping into the Arkansas River is cleaner than the water coming directly out of Cheney Reservoir.”
City Council members will discuss options for a long-term water supply in April. They will hold a workshop March 25 on a cost-benefit water conservation model that can measure actual savings from specific conservation measures.