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A Surplus of Recycled Water


By Hannah Weikel | KUSP News

In Scotts Valley very little water is wasted. A large portion of the waste water goes through a tertiary filtration system and instead of being pumped out to sea, it’s routed through purple pipes and used for irrigation. This process is called water recycling and it has been going on in Scotts Valley since 2002 when the 7 million dollar plant was built.

Photo: Courtesy of Scotts Valley Water District.

Photo: Courtesy of Scotts Valley Water District.

Refined to Near Drinking Standard

“It’s a very natural process,” Waste Water and Environmental Program Manager Scott Hamby says. “The water itself we add a flocculant and what it does is it makes the solids in the water group together to make them easier to filter out.”

The agency also adds methanol which is consumed by bacteria that convert nitrate pollution into nitrogen gas, “and it’s naturally released into the atmosphere,” Hamby says.

Those are the only chemicals used in the process before it is disinfected with ultraviolet lights. Once processed it’s near drinking-water standard. It’s then piped to parks and schools to water recreation fields, landscape medians, and some light industrial sites.

Look for Purple Pipes

The Watsonville waste water treatment plant also recycles water and uses it for watering crops. Driving down Highway 1, some of the purple pipes that carry recycled water are visible amidst the crops.

Hamby says Scott’s Valley hopes to make recycled water more available for residential use as well.

“There’s already quite a bit of residential use in Scott’s Valley. And that’s what we see in the future also, a lot of dual plumbing. So you have potable water systems going inside the house and all outside the home uses recycled water.”

Dual Plumbing

This dual plumbing is currently only available in homeowners associations where the front lawns of homes are hooked up to the same irrigation system. LeAnne Ravinale is the water conservation coordinator for the Scott’s Valley water district.

“Unless you’re in something like that the recycled water is unavailable to you,” she says. “We don’t have the infrastructure to have a pipe to every single house because it’s a redundant system. You have to have separate purple pipe to every single meter.”

So far the district has found users for a little less than a third of the recycled water it has the capacity to produce.

“It’s really just a matter of staffing to get out there and get all the potential customers on board that could be.”

Picking Up for Santa Cruz’s Shortfall, Maybe

One of those potential customers actually came to them: Pasatiempo Golf Course in Santa Cruz. The city of Santa Cruz doesn’t have a recycled water program and the water restrictions in recent years have forced Pasatiempo to return 20% of the course to native grasses. General Manager Scott Hoyt says buying and storing recycled water from Scott’s Valley would give them enough water even during drought months.

“They have excess capacity, they have no customers for it, they have no plans to build out their system,” he says. “They should be giving me a great price on the water.”

Hoyt says some changes would have to be made to the plant and pipeline. The pipeline down to Pasatiempo golf course would have to be sterilized and valves would have to be installed to make sure no water mixing takes place. Hoyt says Pasatiempo is prepared to pay for these modifications. If the plan goes through it would use as much of Scotts Valley’s recycled water as all the current users combined. The earliest their greens will be irrigated by recycled water is September or October of 2014.


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