A city near Phoenix recently greenlit a major indirect potable reuse project designed to support the water supply in an area threatened by drought, rising demand, and climate change.
“Peoria recently approved a $2.2 million project to recover its wastewater — everything that goes down your drain — and inject it on a more mass scale into the ground, where the city pulls its drinking water,” Arizona Central reported, citing city documents.
“New state rules let cities apply to send treated wastewater straight to home taps, but no Arizona city has applied yet. For now, cities use a more roundabout approach than what they'd consider ‘toilet to tap,’ even though traces of the water you flush, after replenishing aquifers, might eventually come to your kitchen sink,” the report continued.
Treated wastewater has already been a major resource in Arizona for decades. It has been used to irrigate crops, water ballparks, and revitalize underground wells, the report stated.
For example, the Scottsdale Water Campus, a potable water reuse facility, is celebrating two decades of recycled water innovation, according to The Scottsdale Independent.
“The facility has enabled Scottsdale to recharge over 65 billion gallons of water into our area aquifers, safeguarding the city’s long-term water supply while ensuring the exceptional water quality of our local aquifers,” the report stated.
Arizona has been actually been reusing wastewater for 90 years, according to Water Deeply. The publication interviewed hydrogeologist Chuck Graf on this backstory.
“We started using reclaimed water back in 1926. And that was at Grand Canyon National Park, when they built a wastewater treatment plant specifically to reuse treated wastewater for steam locomotives and toilet flushing. And they still use it for toilet flushing and landscape irrigation in a much-improved treatment plant,” he stated.
“When they built the first treatment plant in Phoenix in 1931, they actually started distributing that reclaimed water for agricultural irrigation way back then. So it was already being used by the time first rules came into existence in 1972. Then in 2001, we greatly modified our rules for reclaimed water. Arizona probably reuses somewhere above 50 percent, and maybe as much as two-thirds of our treated wastewater,” he continued.
The new rules permitting direct potable reuse make it possible for utilities to plan innovative new projects.
“Our new rule says the source water for this advanced reclaimed water facility would have to go through a multistage, multibarrier treatment process with controls, real-time monitoring, a whole lot of microbial monitoring and chemical monitoring. And the output from that facility is drinking water, and it could be put into a drinking water system,” he stated.
So far, there are no takers.
“We know of no utilities out there that are waiting at the door to come in. The big thing, though, is by having this rule in place now, that utilities and communities can think about maybe this is something we could do in the future and start evaluating this,” he said.
Image credit: "Arizona roadscape," Kevin Dooley © 2008, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/