San Jose’s New Plant Transforms Sewage Into ‘Really Clean’ Water

By Sheraz Sadiq and Olivia Hubert-Allen
KQED News Staff, March 7, 2014

As California’s drought continues, cities across the state are bracing for what could be a very challenging year for the water supply.

Even before Gov. Jerry Brown officially declared the drought a state of emergency in January, current systems were maxed out, leaving little flexibility to handle the needs of farmers, ranchers or other big water consumers.

Water Recycling Comes Of Age In Silicon Valley

Meanwhile, some parts of the state, including Santa Clara County – the state’s fastest-growing county – have been investing in water-recycling technology. The Santa Clara Valley Water District wants to double the amount of recycled water it uses to 10 percent by 2025. So the water district and San Jose are finishing work on a $68 million Silicon Valley Advanced Water Purification Center. When it opens in May or June, it will be the largest water-recycling facility in Northern California, capable of purifying up to 8 million gallons of sewage water a day.

What makes this plant special is the water it produces is really, really clean. Engineers say it is even cleaner than what Santa Clara County residents drink today.

“We hear communities throughout California, throughout the United States and throughout the world talking about becoming energy independent,” says Kerrie Romanow, San Jose’s environmental services director. “Here in Silicon Valley, we’re not only talking about being energy independent but we are also talking about being water independent. And really squeezing the last drop out of every opportunity that we have in our water world.”

The plant turns treated sewage water into purified water through a three-step process: microfiltration, reverse osmosis and ultraviolet disinfection. This technology has been used successfully in places like Singapore and also in Orange County, which has the largest water-recycling plant in the nation.

For now, this ultra-clean recycled water will be blended with the existing recycled water supply that is already being used for things like irrigating lawns and cooling power plants in San Jose and neighboring communities. But one day, it may flow from taps as a sustainable source of water safely recycled for drinking.

For more on how the water is cleaned, read our earlier report “Water Recycling Comes Of Age In Silicon Valley.”

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