California municipal agencies complete stage one of nation's largest water purification project

The Orange County Water District recently completed the first scheduled construction task for the Groundwater Replenishment (GWR) System.

FOUNTAIN VALLEY, Calif., Sept. 28, 2001 — The Orange County Water District recently completed the first scheduled construction task for the Groundwater Replenishment (GWR) System.

A 2,200-foot, 66-inch-diameter pipeline was installed on the west side of the Santa Ana River under the parking lot of the Theodore Lacy Jail in Orange, Calif. This portion was installed well before the remaining 11 miles of pipeline to enable the completion of a new parking lot for the Orange County Sheriff's Department.

The GWR System is a water purification project jointly sponsored by Orange County Water District and Orange County Sanitation District that will provide a new source of high quality water for Orange County residents beginning in 2005. Initially, the system will purify approximately 70 million gallons per day of highly treated sewer water through high-tech membrane treatment processes that include 100 percent processing by reverse osmosis, resulting in near-distilled quality water.

Some of the purified water will be injected underground near the coast to keep ocean salt water from contaminating the fresh water in Orange County's groundwater basin. The remaining water will be transported through a 13-mile pipeline to a percolation pond in northern Orange County. There the water will be filtered again as it seeps into the ground and enters Orange County's deep groundwater aquifers to become part of our future supply of drinking water. The purified water will help lower the overall salinity and hardness of Orange County's groundwater.

Construction of the Lacy portion of the pipeline began in June and ended last week when the last section of pipe was put into the ground. Made of cement and a mortar-lined, coated steel, each pipe is 40 feet long and weighs 23,000 pounds. The pipeline is a key component of the Groundwater Replenishment System.

One of the early decisions involved whether to use cement lining on the pipe, and add a small amount of minerals to the water at the plant before the water entered the pipe, or to use expensive epoxy lining. Because the water produced by the membrane systems is so pure, putting it into a conventional concrete pipe would have resulted in the water dissolving the pipe by leaching the minerals out of the concrete. Using the coated steel pipe and adding minerals to the water will not only maintain the quality of the water, but will be more cost effective to the project.

Future construction of the GWR System will include demolition of the existing world-famous Water Factory 21 water purification facility in Fountain Valley; construction of a new high-tech membrane water purification facility; drilling new injection wells and construction of a pump station to move the water up the 13-mile pipeline to Orange County's aquifer recharge facilities.

This groundwater basin is the main source of water for 2.2 million residents in Orange County.

Orange County Water District is a special agency that was created by the California State Legislature in 1933 to maintain and manage the groundwater basin under northern and central Orange County. OCWD's groundwater basin supplies 75% of the water needs in Anaheim, Buena Park, Costa Mesa, Cypress, Fountain Valley, Fullerton, Garden Grove, Huntington Beach, Irvine, La Palma, Los Alamitos, Newport Beach, Orange, Placentia, Santa Ana, Seal Beach, Stanton, Tustin, Villa Park, Westminster, and Yorba Linda.

Orange County Sanitation District is the third largest wastewater treatment system west of the Mississippi River, serving 2.2 million residents in northern and central Orange County.

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