Flushing away water shortage problems

On Nov. 30, the Orange County Water District, Fountain Valley, Calif., will turn on the world’s largest plant devoted to purifying sewer water to increase drinking water supplies.

By Consulting-Specifying Engineer staff November 28, 2007

On Nov. 30, the Orange County Water District, Fountain Valley, Calif., will turn on the world’s largest plant devoted to purifying sewer water to increase drinking water supplies. The indirect portable water reuse process faced skepticism earlier on from critics who coined it the toilet to tap program and doubted the assurances that the water was reusable.

The plant plans to process 70 million gallons a day, which district manager claim will exceed drinking water standards, but not flow directly into the kitchen and bathroom taps. The Groundwater Replenishment System is a $481 million plant designed to act as a barrier against seawater intruding on groundwater sources and gradually filter into aquifers.

The series of tubing and tanks sucks in treated sewer water from the sanitation plant and runs the liquid through micro-filters to remove solids. The water undergoes reverse osmosis, forcing it through thin, porous membranes at high pressure and than finally cleaned with peroxide and ultraviolet light to break down any remaining pharmaceuticals and carcinogens.

San Diego and other cities in Texas, Colorado, and south Florida have agreed to pilot studies that test the public opinion about the potential for reclaimed water facilities in their towns.

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