Water Cleaning Presents Challenges

Shivaji Deshmukh drinks water extracted from raw sewage. He knows the water is clean because his job is to help make it so as an engineer at the Orange County Water District.

"It's an efficient, cheap water supply — and it's the best quality," says Deshmukh, amid the hiss of machines at the state-of-the-art facility.

Performing the recycling transformation requires a battery of treatments.

Wastewater strained and disinfected at an adjacent sewage treatment plant is first filtered through tiny straws. Then, in a process called reverse osmosis, the water is forced across a spiraled sheet of plastic with holes so small that little else can slip through. In the final phase, the water is zapped with ultraviolet light.

The three-step operation is one of the most sophisticated cleansing systems anywhere. While the incoming water contains minuscule levels of prescription drugs, tests for any traces of a half-dozen pharmaceuticals, conducted as the treated water leaves the plant, detect nothing.

The end product supplies more than 500,000 Orange County residents for a year, nearly one-quarter of the district's potable water needs.

The cleansing procedure illustrates how difficult — and expensive — it is to scrub virtually every iota of contaminant from our supplies.

The standard ways of cleaning water are not designed to snare the tiny amounts of prescription drugs that survive digestion, and then, with a flush of the toilet, begin their journey toward America's taps.

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