Sonoma Valley wastewater clean enough to recycle

Highly treated wastewater is now being produced by a Sonoma Valley plant to use for irrigating vineyards, pastures, golf courses and playgrounds, and to help restore a Napa saltwater marsh.

This recycling is expected to take some of the pressure off the Sonoma Valley ground water supply, which is being depleted in some areas and allowing the intrusion of salt water from San Pablo Bay, according to Sonoma County Water Agency officials.

"There is no silver bullet, but our strategy is you have to tackle it from several different angles," said Jay Jasperse, deputy chief engineer for the Water Agency. "It is a piece of the puzzle. We are looking at conservation, even bringing down winter water from the Russian River and recharging the ground water."

The Sonoma Valley County Sanitation District plant near Sonoma has been operated by the Water Agency since 1995, treating 1.1 billion gallons of sewage a year flowing from 17,000 homes and businesses from Glen Ellen to Sonoma.

Until recently, wastewater entering the plant had been treated to a secondary level, allowing it to be used for irrigation through drip systems and on fodder crops, but it could not released into the bay between May 1 and Oct. 31.

The Water Agency has completed a $6 million upgrade of the plant, adding a filtration and chlorination process, to treat the wastewater to a higher, or tertiary, level, said Jim Zambenini, the plant operations coordinator.

That wastewater, about 5,000 acre-feet a year, is suitable for irrigating vineyards, pastures, golf courses, playgrounds and landscaping that now are supplied by water from wells or the Russian River.

"It's vital, as we can see from the strain on our water resources in California, that we recycle every bit of treated wastewater we can -- especially when you have years like this year, it really shines the light on having that recycled water as a key component of our water structure," Zambenini said.

Sonoma Valley residents and businesses in 2000 used 14,800 acre-feet of water, of which 57 percent was ground water, 36 percent Russian River water and 7 percent recycled water.

Tito Sasaki, who has a 15-acre pinot noir vineyard near the plant, wants to use the wastewater for irrigation in the summer and to spray for frost protection in the spring.

It would replace water he now pumps out of the ground, he said.

"If the recycled water is available, I can stop using ground water, assuming the cost is no more than what we are doing now, and the reliability when we need it," Sasaki said. "That will help preserve the ground water for the region, too."

Kevin Booker, a Water Agency engineer, said the agency is looking for other sites in the Sonoma Valley, including the ball field at Sonoma Valley High School and the landscaping at the Sonoma Mission Inn.

One project is the restoration of two salt ponds totaling 636 acres on the west side of the Napa River back into a salt water marsh. The ponds are part of a complex of 12 ponds, covering 9,460 acres, that were used for the production of solar salt.

You can reach Staff Writer Bob Norberg at 521-5206 or bob.norberg@pressdemocrat

.com.