Orange County Water District and Orange County Sanitation District

Pioneering work to develop the world’s largest water purification plant for groundwater recharge earned the Orange County Water District and the Orange County Sanitation District, California, USA, the 2008 Stockholm Industry Water Award.

People expect water to be there when they turn on the faucet. But in growing arid regions like Orange County in Southern California, sufficient water is not naturally guaranteed. Fortunately for the 2.3 million residents living there, the Orange County Water District and the Orange County Sanitation District jointly developed the Groundwater Replenishment (GWR) system, a water purification system which will provide enough water to meet the needs of an additional 500 000 people without diminishing groundwater resources for current or future generations.

Both agencies have demonstrated how communities can develop, implement and achieve sustainable water reuse.Their extensive involvement of private sector companies such as CDM and Trojan and Siemens, long-term commitment to research and development, and utilisation of cutting-edge technologies has established a model for water-stressed regions to replenish groundwater resources and improve water security.
Mr. Lars Gunnarsson, chairman of the Award Committee.

The GWR System diverts highly treated sewer water that is currently discharged into the ocean and purifies it through a series of advanced techniques: microfiltration, reverse osmosis, ultraviolet disinfection and hydrogen peroxide. The cleaned water is returned to the groundwater basin to increase both water supply and quality. The GWR system has established a blueprint for large-scale wastewater purification that is already being emulated in dry regions and nations, such as Singapore.