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From toilet to tap: how California fights drought

Irrigation water runs along a dried-up ditch between rice farms in Richvale, California.  

California’s historic drought is forcing once-squeamish residents of the Golden State to take a new look at “toilet to tap” water reuse or, as they prefer to call it in Fountain Valley, “showers to flowers.”

The town in conservative Orange County is home to the largest water recycling plant in the world, an example during the epic drought of the life-altering changes California is having to make to avoid running out of water.

This is the third year of drought in the American west. By the end of July, more than half of California was suffering the worst category of “exceptional drought.” The State has made it illegal to hose down a sidewalk or operate a fountain, punishable by a $500 fine. But such measures are largely symbolic, and the state is going to have to do much more.

“Our sources of supply are literally drying up,” said Michael Markus, general manager of the Orange County water district. The State’s main sources of water — snow melt from the Sierra Nevada, imported water from the Colorado river and groundwater — are all in decline. So, for six years, Orange County has been using highly purified wastewater to replenish groundwater reserves.

The Fountain Valley recycling plant produces 70 million gallons a day, turning residential wastewater — from dishwashers, showers, washing machines and toilets — into drinkable water. In February next year, that will rise to 100 million gallons a day, as a $140 million expansion comes online. That will be enough to supply 850,000 people, or about one third of the 2.4 million county residents.

The water goes through three stages of purification: filtration through a series of tiny straws to remove bacteria, reverse osmosis to remove dissolved chemicals, and exposure to ultraviolet light with hydrogen peroxide. By the time it leaves the plant, it is distilled water.

One of the first attempts to move to water recycling, in San Diego in the 1990s, collapsed because of what water managers call the yuck factor. But attitudes are changing. — © Guardian Newspapers Limited, 2014

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Printable version | Oct 28, 2020 5:47:00 AM | https://www.thehindu.com/news/international/world/from-toilet-to-tap-how-california-fights-drought/article6301541.ece

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