Understanding Potable Reuse – A vital water supply solution

When it comes to water, recycling is part of the natural water process known as the hydrologic cycle. Human-generated water recycling, also known as water reclamation or potable reuse, is an integral part of our water portfolio in the Valley.

The AMWUA cities have been maximizing the use of their recycled water for decades. Over that time, it has been utilized to irrigate sports fields, golf courses, and commercial landscapes, create riparian habitats, and stored underground through recharging aquifers so the water can be used during a shortage. As communities throughout Arizona look at accessible ways to augment their supplies, maximizing water recycling is at the top of the list, meaning it has the potential to be used more regularly and needs to be considered an optimal near-term solution for bolstering our water supplies. It is one way our communities can be sustainable for the long term.

To have a better understanding of recycled water, here is some common terminology that is regularly used:

• Effluent: Arizona law defines effluent as wastewater collected from homes and businesses for later treatment in a facility regulated by the Arizona Department of Environmental Quality (ADEQ). These facilities are known as wastewater treatment plants.
   
• Recycled or Reclaimed:  These terms are used interchangeably to describe wastewater treated to a very high-quality level that allows for its reuse for a beneficial purpose.
   
• Potable Reuse: This refers to purified water you can drink. The water is highly treated to meet or exceed federal and state drinking water standards and is safe for human consumption. How potable reused water is delivered determines if it is called Indirect Potable Reuse (IPR) or Direct Potable Reuse (DPR).
   

What’s the difference between indirect potable reuse and direct potable reuse?

• Indirect potable reuse (IPR) is blending advanced treated recycled water into a natural water source—such as a groundwater basin or surface water reservoir—to expand a water supply for public use after further treatment. Indirect potable reuse is allowed in Arizona and used by many cities. Many cities treat their recycled water and release it into a natural waterway. It is recharged and blended in the aquifer and creates an environmental benefit such as the Tres Rios wetlands downstream of the 91st Ave Wastewater Treatment Plant , the largest such plant in Arizona.
   
• Direct potable reuse (DPR) is recycled water that has been treated with advanced technology making it safe for drinking. This technology is already used in places like Texas, Singapore, and Namibia and will become essential to communities facing scarce water supplies. Scottsdale Water is the first provider in Arizona to be permitted for direct potable reuse. While Scottsdale does not deliver this water to its customers, its research into this technology demonstrates how direct potable reuse could become a viable option for areas of the state as water supplies become sparser.
   

Benefits of Direct Potable Reuse (DPR):

• Safe, reliable water supply
• • Potable reuse uses proven technology to purify recycled water to provide a safe water source. Multiple treatment methods separate pollutants, producing extremely clean water.
     
• Sustainable water supply option
• • Potable reuse provides a sustainable and cost-competitive water supply option using less energy than many other options.
     
• Locally controlled, drought-proof water supply
• • Potable reuse is a drought-proof water supply. It can help ensure safe, sustainable water now and into the future.
     
• Independent of weather variability
• • Potable reuse is part of a diversified water portfolio independent of climate or weather.
     

DPR technology exists worldwide, including here in Arizona. And thanks to that pilot project between ADEQ and the City of Scottsdale in 2019, their collaboration provided a valuable blueprint for the future. Next to the significant State investment in water , the most important water legislation this year was HB 2129, which provides ADEQ with the resources to complete a comprehensive DPR regulatory framework, utilize consultant services for technical review, engage subject matter experts, hold public stakeholder involvement meetings, and draft the regulatory language in the next two years. This will provide all-inclusive guidelines for a water utility to follow and comply with if they want to utilize DPR. 

Ultimately, utilizing our recycled water to its full potential is a critical water augmentation strategy – it provides a safe, locally controlled, drought-proof water supply that can be available far sooner than other water importation options.

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