WateReuse Arizona named the Potable Water Reuse pilot tested in Tucson as the 2016 Project of the Year award winner. A handful of UA students and faculty contributed to the six-month pilot that was a tailored collaboration led by international engineering company CH2M HILL and partnered with Tucson Water and the WateReuse Research Foundation.
The project focused on pilot-testing a method of wastewater treatment to see if it could be used for drinking water. While the treated water was not actually used for drinking water because it was a pilot project, it was analyzed and found to consistently meet federal and state requirements for drinking water, according to project engineer Michael Hwang, who works with CH2M HILL.
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Hwang said the treatment of the wastewater draws on different processes that have been used to treat wastewater for other uses, like irrigation, but this project is the first to combine some of these processes to treat the wastewater effluent to be suitable for potable water.
To be treated in the pilot project, the wastewater goes through different treatment barriers. These include a soil aquifer treatment through wastewater effluent’s recovery and recharge, nanofiltration, ozone oxidation and granular-activated carbon that is operated in adsorption and biological filtration modes, according to Hwang.
There are efforts similar to those in Tucson to treat wastewater taking place around the world, but this project in Tucson is unique because of its combination of engineering and natural processes, according to Shane Snyder, a UA professor of chemical and environmental engineering.
Snyder and fellow chemical and environmental engineering professor, Robert Arnold, had research groups who worked on the pilot project by operating the plant and analyzing the water quality.
Snyder said those involved in the project had to be clever in their work to ensure they didn’t waste any water because technologies used in similar projects in coastal cities aren’t as efficient for inland cities like Tucson because there is not an ocean to discharge waste stream into.
Hwang said Tucson Water’s participation in the pilot stemmed from their interest to plan for the future. The city doesn’t need potable reuse of water right now but the potential need may arise in the future, depending on water scarcity.
“I think the genesis of the project is the fact that there’s still an epic drought in the Colorado river which is the main source of water for southern Arizona,” Snyder said. “The city and the county have become vastly interested in how to, if you will, get more mileage from our water.”
The project was started in 2013. After the involved organizations designed the plant and set up the equipment. Pilot testing ran from October 2014 to April 2015, a time period selected to be during Tucson Water’s off-peak reclaimed water demands.
Some parts of the project were “almost entirely run by students” while being overseen by professors, which provided opportunities for student engagement, according to Snyder.
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Hwang said some UA students working on the project went to the facility almost every day to monitor the process and collect samples to be analyzed.
The project, now complete, is the winner of the 2016 Project of the Year award from WateReuse Arizona. The selection committee who chose the winner of the award, comprised of Arizona water professionals working in academia, municipal water sectors and consulting engineering, looked for projects focusing on reclaimed water quality, the use of reclaimed water and contributions of public education, according to Bradley Hill, the utilities director for the City of Flagstaff.
Hill said via email the selection committee thought that, after being fully tested, the pilot project could one day be applicable to other Arizona water providers who may need to expand their water portfolios.
Hwang said it was an honor to have the project win this award.
“This was a really cool project—it was a great example of collaboration and also an example of a utility preparing for the future,” Hwang said. “There’s a lot of excellent work done from everyone on the team.”
Hwang said the next step in the development of the water treatment could be Tucson Water’s construction of a demonstration treatment plant in the near future. The demonstration plant would run the treatment process for a couple years to collect more data and optimize the project before it could construct a full-scale facility.
Snyder said that there is work to be done in public perception and acceptance of the use of treated wastewater.
“I think what we’ve done is we’ve demonstrated that the technologies will work efficiently and produce a very safe, very pure water. But whether or not the city employs it is really a political decision,” Snyder said. “That’s where the science ends and the politics begins.”
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