The US$487 million ‘Groundwater Replenishment System’ takes highly treated sewer water that is currently released in to the ocean, and purifies it using the same technologies that purify baby food, fruit juices, medicines and bottled water.

It will use a combination of microfiltration, reverse osmosis, and ultraviolet light with hydrogen peroxide treatment, and allow it percolate into the groundwater basin along the same natural filtering path rainwater takes through the ground. Water will also be injected along the coast to maintain a seawater intrusion barrier to keep the Pacific Ocean out of the groundwater supplies.

Denis Bilodeau, president of Orange County Water District, said the system would serve as a model for water management professional throughout the world. “The GWR System is the first water purification system of its kind in the world and will be emulated by water suppliers in regions across the globe facing similar water supply, population and climate challenges.”

Phase One of the GWR System is currently online and sending five million gallons of purified water to the county’s seawater intrusion barrier to prevent salination of the aquifer. Construction has now begun on the larger, 70 million gallons per day facility.

Steve Anderson, Chair of the Orange County Sanitation District, said: “It’s environmentally beneficial because it improves water quality and drought mitigation, saves energy over importing water from Northern California, delays the need for an additional ocean outfall, reduces the amount of wastewater to the ocean. And, because it reduces the need for imported water from Northern California, it lessens the strain on the ecosystem of the San Francisco – San Joaquin Bay Delta.”

More than half of the area’s water supply for 23 northern and central Orange County communities is drawn from groundwater aquifers, with the remainder imported from the Colorado River and California’s State Water Project.

By David Hopkins

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