Last month, I wrote about the winners of the 2014 U.S. Water Prize, a program that celebrates "one water" champions - be they public, private, industrial, or non-profit. Since then, I’ve had the opportunity to speak with one of the winning project teams and learn more about their remarkable accomplishments.
The Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD) are two separate and distinct agencies serving some two and a half million people in north and central Orange County (California). More than forty years ago, despite the then-traditional idea that drinking water and wastewater were separate 'siloed' initiatives, these two progressive agencies realized that their missions were deeply intertwined.
In the 1970s, the OCWD built and operated Water Factory 21, a project designed to mitigate seawater intrusion. It was the first plant in the world to use reverse osmosis to purify wastewater to drinking water standards. That wastewater was supplied by OCSD at no charge. And thus began their partnership.
Twenty years later, in the 1990s, OCWD needed to expand Factory 21 to address continued problems with seawater intrusion. At the same time, OCSD needed to expand its ocean outfall to meet peak wet weather demands. "So the two agencies got together and decided to build the Water District's facility to a higher flow to be able to treat those peak wet weather events for the Sanitation District," said Michael Markus, OCWD's general manager. And so the Groundwater Replenishment System (GWRS) was born.
The GWRS is the largest planned indirect potable reuse facility in the world. Treated wastewater comes into the facility and undergoes advanced water purification - a three-step process of microfiltration, reverse osmosis, and UV disinfection. About half of this "new quality" water is injected into the expanded seawater barrier. The other half is piped to lakes in Anaheim where it filters through the ground and mixes with imported water and Santa Ana river water in OCWD's groundwater basin. Finally, it is pumped out for drinking water.
Both agencies shared the cost of constructing the facility and OCSD continues to provide treated wastewater at no charge. In turn, OCWD agreed to manage and fund GWRS operations. "It benefits the Sanitation District in that we didn't have to construct a new ocean outfall," said Jim Herberg, OCSD's general manager. And for OCWD, the Groundwater Replenishment System provides a reliable drought-proof solution to sustaining water supplies.
"It was a very difficult project," said Markus, "and it took over ten years of collaboration between the two agencies." But one of the biggest keys to success, he said, was cooperation. "We are different agencies, we're different special districts," he said. "So to be able to come together and agree to build this project and to continue to operate it really is phenomenal."
The GWRS currently produces 70 million gallons of ultrapure water per day. But by 2015, it will be expanded to produce an additional 30 million gallons per day. Ultimately, through another expansion project, the two agencies expect the GWRS to eventually have a capacity of 130 million gallons per day.
Chief Editor, WaterWorld
