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San Jose's High-Tech Drought Savior

A treatment center that turns waste into water, safe for the drinking.


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As parched California stares down the barrel of another long, dry summer, San Jose is responding with a one-two punch: a team of facilities, one brand-new and one that’s been working continuously since 1956, that together turn sewage into drinking water, taking millions of gallons of regional water use “off the books.” Right now the city is not allowed to distribute its recycled water for drinking, but with the state going into crisis mode and few rain clouds on the horizon, that is destined to change soon.

For decades, San Jose’s hardworking wastewater treatment facility has been turning sewage into bay water. It takes the South Bay’s least marketable output, strains out the trash, and then removes the organic waste—crap, you might call it—by feeding it to swarms of ravenous microbes (the remains of which are later burned to generate electricity for the plant). The resulting water is clean enough to be dumped into the bay without posing a danger to local wildlife, but you wouldn’t want to drink it. That’s where the Silicon Valley Advanced Water Purification Center, a $72 million facility that opened last year, comes in.

Every day, a small portion of the sewage plant’s output is delivered to its new sister facility, where it’s filtered through increasingly fine plastic and metal screens, their final mesh tiny enough to catch anything larger than a single water molecule. Salts and other minerals are dissolved with hydrochloric acid (a separate treatment later restores the water’s pH balance). The water ends its journey in gigantic tanks bristling with plugs, where 40 UV lights set at “the exact wavelength that deactivates the DNA in any living thing,” according to facility manager Pam John, zap the microorganisms that somehow made it this far.

A pint of water travels through the works in two and a half hours, going from what is essentially bay water to a product that recalls those mountain springs on bottle labels. The result is up to 8 million gallons a day of what in common parlance is called recycled water (enough to quench the thirst of tens of thousands of Santa Clara Valley Water District customers). The budget-friendly clincher: Only one person is needed to operate the entire facility. It’s a model of 21st-century ingenuity— with one shortcoming: Right now, the plant is not allowed to sell a single drop for drinking.

Southern California, on the other hand, has been swigging recycled water since 2008. In fact, the San Jose plant is modeled on one in Orange County that’s identical except for the splash of disinfecting peroxide that Orange County throws in at the end. But San Jose can’t distribute its water for potable use until it gets permits and a thumbs-up from the State Water Control Board. The product is probably safe right now— several water commissioners cheerfully downed beakers of it at the opening ceremony last year without consequence (we asked). But because “the delivery method involves putting treated water back into the groundwater source,” says Randy Barnard, spokesman for the water board, “a number of site-specific studies are required.”

The original timetable had that process taking up to five years, but now, in the midst of a nightmare drought, the city might make its pitch to the state within a year or two. In the meantime, it sells recycled water to about 800 clients who use it for irrigation and other industrial purposes.

Paperwork is not the only issue, however—the other potential obstacle involves PR. People have a natural aversion to what CNN rather unhelpfully described in a 2014 story as the “toilet to tap” model, and similar facilities in other cities have met resistance from squeamish consumers. Their qualms about recycled water were likened by the CNN story to a fear of voodoo and folk magic: an irrational belief, but so deeply ingrained that people remain anxious even when presented with sound science.

That’s why the Silicon Valley plant, which offers public tours, is clearly tailored to give the impression of spotless space-age wonder. The interior is whisper-quiet (all the noisy pumps, which suck water from 20 feet underground, are outside), and the water is never exposed to open air. Even the words “Silicon Valley” on the sign suggests a place where slick, efficient, and, above all, clean 21st-century technology performs miracles.


Originally published in the June issue of San Francisco

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