The FLEWR team (left to right): Dr. Jim Crook, Dr. Bob Cooper, Bob Holden, Dr. Kara Nelson, Dr. Gordon Williams, Tom Kouretas and Dr. Bahman Sheikh.

Four-year FLEWR Study Complete:
Agency Awaits Final Approval to Run at Higher Filtration Rates

Phase II of the Filter Loading Evaluation for Water Reuse (FLEWR) has ended. "We have shown that safe recycled water can be produced at a 50 percent higher filter loading rate than the long-standing maximum of 5 gallons per minute per square foot of filter surface area," states Tom Kouretas. "However, we're not quite at the end yet. We're waiting for the California Department of Public Health (CDPH) to sign off on the results and pass along their approval to the Regional Water Quality Control Board, which will give us, hopefully, a waiver allowing us to run the SVRP facilities at the higher loading rate."

From a practical standpoint, plant operation at the higher loading rate can mean significantly more recycled water production.

Phase I of the study, from summer 2004 through fall 2005, involved constructing a mini plant that mirrored normal plant operations. "The pilot study showed that it could be done," Tom says. "In the summer of 2007, we went full scale, stopping at the end of the growing season that year, then restarting with the 2008 season."

A stipulation by the CDPH was for the study to be overseen by a "third party to maintain impartiality," Tom explains. "Dr. Kara Nelson, a wastewater reuse expert from UC Berkeley (pictured right in the filter gallery), and one of her graduate students, Gordon Williams, who has since been awarded his PhD, were the independent principal investigators. Dr. Bahman Sheikh, also an expert in water reclamation, recycling, and reuse, served as a private consultant. They have said, 'Looks like we're there. You're done.'"

Within the Agency, Bob Holden served as internal reviewer and coordinator. Tom oversaw the ground operations from start to finish. "Our plant operators played a major role in the study," he says. "They were exceptional through the 90 or so long, difficult tests, collecting samples and watching closely over the chemical dosage. They got really good at putting together exactly the right chemical dose regimen. James Dix steered the ship, effectively communicating to the operators how important their work was. The entire study would have been impossible without the people in the lab. They went through many hard, hard weeks, often volunteering to be available at odd hours – because the testing had to be coordinated with often irregular orders for recycled water."