BY: Warren Tenney

Expanding the Beneficial Reuse of Recycled Water

Published Nov 18, 2019

Our planet only has a finite amount of available freshwater. And over the course of time, our water has always moved through a natural cycle of use and reuse. As we move forward with a better understanding that we only have “One Water” we will look to manage and utilize all of it to its full potential regardless of source - groundwater, surface water and yes even wastewater. This will help ensure our communities are sustainable for the long-term.

Until recently, each of those water sources needed to be seen separately and uniquely, due to their distinctive differences, but with the evolution of treatment technology, the “One Water” approach is now possible and allows water providers to continually treat and reuse all of our water, over and over again.

Last year, Arizona took a big step forward in this approach when the Arizona Department of Environmental Quality (ADEQ) officially made the decision to approve permits for the direct use and consumption of treated recycled wastewater after extensive analysis and research including stakeholder input.   

The main motivating factor for allowing water providers to gain such a permit was to look at ways to improve the sustainability of Arizona’s water supplies and expand the beneficial reuse of treated wastewater in the State. However, they needed to establish a more detailed process for how cities could build their infrastructure and testing protocol to qualify for such a permit. So ADEQ began looking for demonstration projects which would assist with developing that process for moving forward and would ensure proper steps in the regulatory process would be established. This would also assist in the creation of a blueprint for water providers looking to utilize Direct Potable Reuse (DPR) as an alternative water supply in Arizona.

Last fall, ADEQ and Scottsdale Water met to discuss a possible demonstration project that would help them develop that protocol and create a viable outline for moving forward and utilizing DPR to its full potential. It was the ideal collaboration as Scottsdale has already been utilizing this innovative technology at their Advanced Water Treatment Plant for over 20 years. And while the water being produced at Scottsdale Water’s Advanced Treatment Plant is considered ultrapure, even exceeding bottled water quality standards, it could not be used for direct consumption, and instead needed to be used in other ways.

All of the AMWUA cities have been maximizing the use of their treated wastewater for decades. Over that time, it has been utilized to irrigate sports fields, golf courses and commercial landscapes, create riparian habitats, and recharge groundwater aquifers for storage underground for use during a shortage. But never has it been permitted to be used for direct human consumption, until now. The City of Scottsdale has become the first to demonstrate how that can be done after being granted Arizona’s first permanent water treatment facility permitted to treat recycled water for DPR.

Earlier this month, their demonstration project - the One Water Brewing Showcase at the Scottsdale Waterfront, as part of Canal Convergence, took place. The Showcase was a joint effort between Scottsdale Water and Scottsdale Arts to celebrate the historic permit and showcase how DPR can be utilized and consumed. The event brought together ten of the Valley’s most popular craft breweries to serve specialty beers brewed specifically for the event with the advanced treated recycled water. Although Scottsdale’s demonstration project was a sipping success, they will not be sending recycled water into their drinking water system anytime soon. Instead, the one-of-a-kind event was designed to help the public better understand and become comfortable about the purity of recycled water, another obvious obstacle many water providers will face moving forward.

To increase acceptance of DPR it will be important to ensure everyone understands the rigorous and regulated treatment and testing process all DPR must adhere to under ADEQ regulations. This means that after reclaimed water is treated at a wastewater treatment facility, it is then required to be treated a second time at an Advanced Water Treatment Facility, like Scottsdale’s, where the water goes through a variety of advanced treatment steps to ensure it meets all drinking water standards including ozonation, ultrafiltration, reverse osmosis and ultraviolet light disinfection. These additional treatment steps also bring forth added costs which are another hurdle water providers will need to deal with when deciding if DPR is the best option as an additional water source.

In the end, we know the technology for DPR exists, water providers in Singapore, Australia, Texas and locally here in Scottsdale have successfully proven that. And through their collaboration with ADEQ, a valuable blueprint for the future has been created. This means the opportunity for water providers to utilize DPR could become a viable option for areas of the State as water supplies become more sparse.  In the end, we must recognize that utilizing our “One Water”, with the help of innovation and technology, will enable us to build resilient and sustainable communities, so cheers to DPR!

For 50 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit .

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