Clear bluish water swirls in a concrete basin off Eighth Street East, birds fly overhead and off into the distance. Brian Anderson walks along a metal railing that flanks the flowing water and takes a moment to appreciate it. This water has come a long way – from toilets, showers, garbage disposals – and now it will have a chance to be used again.
Anderson, a Sonoma County Water Agency administrator, oversees the Sonoma Valley Wastewater Treatment Plant on Eighth Street East. Along with SCWA, and in addition to his work at the treatment plant, Anderson helps maintain water quality for, and distributes water to, more than 600,000 people from Sea Ranch to Marin. Currently, SCWA has 14 customers who use recycled water; 300-acre feet for pasture irrigation, 1,095 acre-feet for vineyard irrigation and 5 acre-feet for construction. Through a partnership with the California Department of Fish and Wildlife, the water agency also sends approximately 15 acre-feet of recycled water to the Napa-Sonoma Marshes Wildlife Area at the northern edge of San Pablo Bay.
The plant moves through 2.5 million gallons of water a day, Anderson said. But this past dry year, there has been less water and more demand, with agricultural producers looking for more water sources. From Jan. 1 to Dec. 31 in 2013, 850 million gallons of wastewater were pumped and treated at the recycled water treatment plant. In 2012, 1.2 billion gallons went through.
With the statewide drought and local farmers and vineyard workers looking at smaller crops this year, recycled water is viewed as a valuable alternative to using precious potable water for irrigation. Recent SCWA studies done with the United States Geological Survey, show groundwater supplies in the Sonoma Valley are declining, especially in deep aquifers. And, saltwater intrusion on groundwater basins that dip below or just at sea level, increase water salinity and make it undrinkable.
Kevin Booker, a water agency principal engineer, says the Sonoma Valley plant currently produces 4,500 acre feet of recycled water a year to irrigate the southern part of the Valley, where the district has pipelines. The water, which is not potable, is becoming more and more used for vineyard and pasture irrigation. Recycled water users pump the water onto their properties from SCWA’s pipeline, or truck it in.
This year, the water agency received more calls from existing recycled water users, looking to ensure their supplies, and interested potential users who want to know when the resource will be made available in their area.
“It’s a drought-resilient water method,” Booker says, adding people who are not using recycled water have little to no option in a drought, with depleted reservoirs and declining groundwater supplies.
Water travels through the sanitation facility in a complex, scientific process, through a system of pumps and retaining pools, or basins. The plant, Anderson explained, takes in wastewater from Sonoma and up to Glen Ellen. Raw sewage is filtered, with solid waste and debris removed, then goes through a biological process in which bacteria helps to rid the water of nitrogen through a continuous 28-day cycle, with more water from the initial stage pumped in during that time. The goal, he explained, is to get this water to as neutral a state as possible by controlling the amount of microbes that are present and having the bacteria do the work of eating away the contaminants.