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Health and sanitation
Direct potable reuse moves closer to reality in state of California
By Mike Flenniken at IAPMO
Russ Chaney
In the spirit of the sharing of unique experiences that shape the plumbing industries in our respective nations, the following article looks at the feasibility of developing water recycling criteria for direct potable reuse in California, US. Written by IAPMO staff writer Mike Flenniken, it is the next in a regular series of similar articles that will be run in this magazine.
California is laying the groundwork to become the first state in the US nation to directly mix treated sewer water with drinking water.
The State Water Resources Control Board recently released a report that concluded it is“ technically feasible to develop uniform water recycling criteria for DPR( direct potable reuse) in California, and that those criteria could incorporate a level of public health protection as good as or better than what is currently provided by conventional drinking water supplies and IPR( indirect potable reuse).”
Randy Barnard, chief of the Recycled Water Unit with the State Water Resources Control Board, said two state Senate bills that passed in 2010 called for three things: finish regulations on groundwater recharge regulations; develop regulations for surface water augmentation; and produce a report on the feasibility of developing DPR regulations. Barnard said the first part was completed in 2010; the surface water augmentation regulations are being finalised; and the recent report represents the third part.
According to the report, there are two DPR projects in the world that serve as permanent sources of drinking water. One is in Windhoek, Namibia, and the other is in Big Spring, Texas, and both“ were pursued out of necessity after the communities suffered through severe drought, despite conservation efforts and efforts to find better sources of water,” the report notes, adding that“ the regulating authority provides oversight of the projects via a site-specific permitting process rather than via a uniform regulatory process that would be applicable to other facilities.”
Barnard said the report took into consideration a panel of 12 world-renowned experts from multiple fields— as required by the legislation— and an advisory group consisting of 15 stakeholders who were key components to coming up with practical considerations that must be considered for DPR. They then conducted an exhaustive literary review and looked at different projects around the world that were contemplating DPR-type of projects.
“ We brought all that information together with our expertise on permitting drinking water systems that have impaired sources, which would be a similar type of project, to form this report,” he said.
While the report found it is technically feasible to move forward with developing DPR regulations, Barnard said, it also pointed out some key research issues and knowledge gap areas that must be completed before any regulations are finalised and adopted.
“ We’ re going to move forward with developing our DPR regulations concurrently with research studies that are moving forward to answer those questions that we need to get answered,” Barnard said.“ So, we’ ll be moving at the same time as the research is, and then sometime in the future they’ ll come together, we’ ll have the answers, and we’ ll be able to finalise our DPR regulations.”
Barnard said one of the major obstacles is coming up with a way to write unambiguous, measurable, objective criteria that would protect the public health, because the two groups identified several issues that must be addressed for DPR to move forward. For example, the groups said the regulations need a‘ diverse’ set of processes and‘ rigorous’ response protocols, so it needs to be determined how to define what is meant by diverse and how to define rigorous, he said.
“ There’ s still a lot of things we’ ve got to figure out,” he said,“ but it’ s nothing that’ s going to stop us from starting to draft up DPR regulations.”
As projects involving DPR move forward, Barnard said that community education, such as public hearings and meetings, will play an important role. He pointed to recent studies showing that public fears about indirect potable reuse— including groundwater recharge and surface water augmentation— decreased dramatically after people were shown a brief presentation.
“ I think that a big key is public education,” Barnard said.“ We have to be transparent and let them know what the processes are, what the treatment requirements are, and how regulations are going to be put in place
April 2017 Volume 23 I Number 2 www. plumbingafrica. co. za