Groundwater Replenishment System receives AAEES Grand Prize for Design

April 26, 2023
The recently-completed potable reuse project was recognized by the American Academy of Environmental Engineers and Scientists during the academy’s virtual conference on April 13.

Orange County, California’s recently-completed Groundwater Replenishment System (GWRS) has been recognized by the American Academy of Environmental Engineers and Scientists (AAEES) with the Grand Prize for Design, according to a press release from the Orange County Sanitation District.

The award was presented virtually during the AAEES Conference on April 13.

A joint project of the Orange County Sanitation District (OC San) and the Orange County Water District (OCWD), the GWRS made history when it came online in 2008, overcoming the stigma associated with potable reuse projects.

The GWRS started producing 70 million gallons of water per day (MGD) in January 2008 and increased production to 100 MGD after an expansion was completed in May 2015.

Now, with the final expansion completed, GWRS is producing up to 130 MGD, enough to serve nearly one million people. This is due to OC San and OCWD meeting its goal of recycling 100 percent of OC San’s reclaimable flows.

To reach this goal, OC San had the complex task of making additional water available for GWRS. Water from OC San’s Plant No. 2 in Huntington Beach was considered unsuitable because it contains industrial flow. To make the water usable, OC San had to separate reclaimable from non-reclaimable flow by splitting the headworks process while maintaining operations of the critical asset.

“This unique location makes the headworks one of the most critical water pollution control facilities in the state,” stated OC San Board Chairman Chad Wanke. “Continuous and reliable operation of the 317 million-gallon-per day headworks was paramount to protecting the coastal environment, public health, and the regional economy and we made it happen without incident.”

The GWRS takes highly treated wastewater and purifies it using a three-step advanced treatment process. The result is high-quality water that is pumped to recharge basins in Anaheim where it naturally percolates into the Orange County Groundwater Basin and becomes part of the drinking water supply for 2.5 million people in north and central Orange County.

GWRS water is also sent to injection wells located along Orange County’s coast to create a seawater intrusion barrier that protects groundwater supplies. Over the years, GWRS water has become a primary source used to refill the basin and has allowed agencies served by OCWD to pump more water from the basin and become more locally sustainable.

“We celebrate the achievement made possible by the unique, longstanding collaboration of our agencies,” said OCWD Board President Cathy Green. “This project provides local reliability to our region, decreases our dependence on imported water and serves as a model for the rest of the world.”