Direct Potable Reuse is Coming, but What Does It Mean for Operators?

As states look to combat dwindling water supplies with DPR projects, operators in some regions could see a changing water treatment landscape.
Direct Potable Reuse is Coming, but What Does It Mean for Operators?

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Communities in California and Arizona could be more drought resistant in the near future, as both states are looking at enacting regulations for direct potable reuse (DPR) — where treated effluent flows directly into a drinking water supply rather than using an environmental buffer (indirect potable reuse). And those new regulations likely will mean new training and certifications for the treatment plant operators working in drought regions.

In California, the State Water Resources Control Board (SWRCB) recently wrapped up a report concluding that it’s feasible for the state to write new regulations allowing DPR as long as some research and knowledge gaps are addressed.

Meanwhile, the Arizona Department of Environmental Quality will likely propose legalizing and regulating DPR sometime this year, according to the department’s senior hydrologist, Chuck Graf.

The effort in California saw the board take advice from an expert panel administered by Jeff Mosher, chief research officer of the Water Environment & Reuse Foundation. Mosher — who took the time to speak to — has comprehensive experience in water supply and water resources issues, and he’s focused on indirect and direct potable reuse.

Although SWRCB agreed with the expert panel that it’s feasible to create DPR regulations, it reported that those research and knowledge gaps must be addressed while the board begins work on the rules.

“The research recommended by the expert panel and endorsed by SWRCB can be done concurrently in developing DPR regulations in California,” says Mosher. “That is, regulations can be developed without a delay. The research recommended is intended to collect information that would help in developing the regulations.”

The complexity of operating an advanced treatment plant will necessitate a new advanced operator certification program to ensure proper management, according to Mosher, the expert panel and SWRCB.

“Regarding how a DPR project would affect a wastewater treatment plant and its operations: the wastewater treatment plant would need to be operated differently since the effluent would be used for a different purpose — as the influent for an advanced treatment facility,” says Mosher.

In other words, Mosher says, WWTPs would be optimized to produce higher-quality effluent for the DPR stage in order to adequately protect public health.

“As a result, the operators would need to know the new procedures,” he says. “The operators would also have to be in communication with the advanced treatment plant operators to ensure proper operations.”

DPR would allow communities to rely less on potable water supplies and reduce the impact of droughts, according to Mosher.

“This would reduce demand on existing supplies,” he says. “However, water conservation and water efficiency will continue to be a significant effort by all communities because it will still be good policy. DPR will improve water reliability for communities. As a result, communities will be more resilient to droughts and the risk of climate change.”

Although it’s still in its infant stage, it’s clear that DPR use is on the horizon for at least some of the drought-stricken areas of the country. In fact, a few communities in Texas and New Mexico are already using DPR treatment, and the Water Research Foundation has seen it coming for some time. The foundation recently released preliminary results from a project titled “Blending Requirements for Water from Direct Potable Reuse Treatment Facilities.”

Check out the video below for more details on that study and what DPR could mean for the future of water supply and treatment.


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