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Earlier this week, a crowd of mostly government officials and employees gathered around a colorfully painted shipping container stationed outside the city of Flagstaff’s Rio de Flag Wastewater Treatment Plant. One side of the container was open to the crowd, showing a system of tubes, pressurizers, tanks and filters that looked like a giant science experiment.

But the setup is far beyond the experimental phase. In fact, it is a portable water treatment system being hauled across the state via semi truck. Its multi-step process treats reclaimed wastewater to the point of being clean enough to drink.

The truck is making its rounds to spread awareness about advanced treatment processes that can make wastewater potable again — a technology many see as promising to bolster the state's water supplies in the future. To help promote public education and acceptance, more than 30 Arizona breweries have agreed to brew beer with the potable water from the truck later this summer as part of what's called the AZ Pure Water Brew Challenge.

The initiative comes at a time when state environmental regulators are nearing completion of interim rules that will allow utilities to treat reclaimed wastewater for drinking water reuse. A draft of the rule came out last week.

The state's process is being watched closely in Flagstaff as the city has already begun its own assessment of the cost and feasibility of advanced wastewater treatment.

“For Flagstaff it gives us one more tool in our toolbox for future water supplies should the community elect to go that route," said Brad Hill, utilities director with the city of Flagstaff.


On Monday, the Pure Water Brew truck had its first go at processing water from the Rio de Flag facility. It was the first time the system was being used to treat water from a city participating in the brew challenge, while the truck’s statewide tour marks the first time that wastewater is being treated for reuse as drinking water in the state of Arizona, said Channah Rock, a water microbiologist who is leading public outreach for the Pure Water Brew Challenge. The city of Scottsdale does a similar treatment process, but only injects the water into the ground to recharge aquifers, Rock said.

Inside the shipping container on Monday, Flagstaff's treated wastewater went through several steps including ultra filtration to block bacteria and other small organisms, reverse osmosis to dissolve things like salts, minerals and pharmaceuticals, and ultraviolet disinfection with advanced oxidation to break down the DNA of bacteria and viruses.

Next, the final product will be sent through a barrage of water quality tests, with results expected in a few weeks, Hill said.

The initial run-through of the advanced treatment process will be a big step for Flagstaff’s utilities department as it evaluates the potable reuse of treated wastewater as a part of the city’s long-term water supply plan. Hill stressed that something like this has to be done right the first time because of the risk to public health and the fact that “it is a challenging thing for people to get over the fact of drinking reclaimed water.”

"We can't get this wrong," he said.

After tests are back and if they show the treatment was successful, the Pure Water Brew truck will come back up to Flagstaff in August. It will again run reclaimed wastewater through its system and then truck it to four breweries, which will use it to make beer specifically for the challenge. Flagstaff's participating breweries are Historic, Wanderlust, Lumberyard and Mother Road.

The concept of making beer with the newly potable water is a great way “to help break down that yuck factor barrier," Hill said. The reuse of wastewater for human consumption has long battled the “toilet to tap” label, he said.

For its part, Flagstaff's utilities department has already started an updated economic analysis of the city's future water supply options, and it includes a much more in-depth look at indirect and direct potable reuse than the city has ever done, Hill said. Next year, the city will take a deeper look at feasibility of the treatment technology as well. 

That way, as the city evaluates future water supplies, it will have the same level of detail and analysis for direct potable reuse as it will have for the other main alternative of pumping and piping groundwater from the city-owned Red Gap Ranch property about 40 miles to the east, Hill said. Current estimates put the cost of that project at $200 million.

Hill estimated that new decisions on future water supplies — including whether to move forward with Red Gap or more advanced treatment on wastewater — will face the city in about two decades.

Currently, advanced treatment of wastewater still faces a big hurdle of getting public buy in, Hill said.

“For these projects to be successful you have to have the public behind it,” he said. “We are trying to get people to think about not judging water on history but its quality.”


After more than a year of work, the Arizona Department of Environmental Quality last week released draft rules for allowing utilities to treat wastewater for potable reuse, said Chuck Graf, principal hydrogeologist with the agency.

The rules are interim because they will eventually be replaced with more permanent, and much more detailed regulations for the process, called direct potable reuse, Graf said. Two groups of experts are currently developing recommendations about criteria that should be included in the permanent rule, he said. 

Already, several states have laws or are in the process of creating laws that allow for direct potable reuse and both Graf and Hill said the technology is readily available.

“We think it’s about time that ADEQ is willing to look at this,” Hill said. “The utility industry is already there, we've developed these tools and treatment processes, so it is nice to see the regulatory aspect is beginning to catch up.”

Graf echoed those points.

“I think everyone including our department have been convinced that the technology exists. We can treat any source water we want to virtually any standard we desire,” he said.

Heading into the future, it is important that the state consider alternatives like reusing wastewater for drinking water, Hill said.

“As we look forward, for local communities this is a supply we can control and it’s the only supply that grows with a community,” Hill said “So how can we use it more beneficially than only for irrigation?”

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Emery Cowan can be reached at (928) 556-2250 or


Environment, Health and Science Reporter

Emery Cowan writes about science, health and the environment for the Arizona Daily Sun, covering everything from forest restoration to endangered species recovery efforts.

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