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Eastern Municipal Water District (EMWD) was honored last week by the national WateReuse Association with its Transformational Innovation Award for EMWD’s work in helping to pilot test a technology to reduce salts in recycled water.
EMWD was recognized at the WateReuse National Conference in San Antonio, Tex., where it received the award for its Closed Circuit Reverse Osmosis (CCRO) pilot project.
The WateReuse Association is a trade association whose mission is to advance laws, policy, funding, and acceptance of recycled water. EMWD is one of the nation’s leading recycled water agencies and meets more than one-third of its overall water supply needs through the use of recycled water for irrigation of agriculture, parks, schools, recreational facilities and environmental benefits.
“On behalf of EMWD, we are incredibly honored to receive this award and wish to thank WateReuse for this recognition,” EMWD Board President Phil Paule said. “EMWD was excited to help pilot test this new technology, which we believe has a role in creating a more sustainable water supply future for our industry.”
In 2020, EMWD launched the pilot project using a proprietary CCRO technology developed by DuPont. The project concluded in mid-2021.
Traditional reverse osmosis technology sends water through reverse osmosis membranes, with the reject water being sent to the end of the treatment plant and disposed of through a connection to a brine line. At EMWD’s Desalination Complex, the standard recovery rate is approximately 75 percent, which is in line with the industry standard for use in reverse osmosis technologies.
The CCRO technology had the potential to improve that recovery rate to nearly 95 percent. Instead of discharging the reject water, this technology sends it back to the front of the plant, where it is blended with additional source water and then treated again. This process is continually repeated until the brine concentrate reaches a prescribed level, and that higher-concentrated brine is then discharged in a “batch” as opposed to a continuous stream of lower-concentrated brine.
EMWD pilot-tested the CCRO technology on recycled water to determine if it could be an effective and cost-efficient way to reduce brine as part of its planned Purified Water Replenishment (PWR) program. EMWD is in the design phase of its Purified Water Replenishment program, which will further clean recycled water so it may be used to replenish groundwater supplies and eventually become drinking water.
The CCRO pilot project is the first time this technology has been tested on recycled water. Because EMWD’s San Jacinto Valley Regional Water Reclamation Facility, where its PWR facility will be built adjacent to, does not have a connection to a regional brine discharge pipeline, EMWD tested the technology in hopes it could reduce the size of brine evaporation ponds that will be needed with the facility.
EMWD received funding and technical support for the pilot program from the State Water Resources Control Board, The Metropolitan Water District of Southern California, Desalitech, and Cal Poly Pomona.
“EMWD is proud of the leadership role it has taken in the recycled water industry for many years,” Paule said. “We are always seeking ways to move our industry forward with new technology, and this program is a representation of those efforts.”
