Spill of partially treated wastewater at Russian River County Sanitation District Treatment Plant

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Beginning late in the evening of Friday, March 1 into the early morning of Saturday, March 2, the Russian River County Sanitation District Treatment Plant experienced a spill of secondary treated wastewater. The cause of the spill is believed to be related to the weekend storm event.

Estimates indicate that less than 277,000 gallons of secondary treated water spilled within the treatment plant property. A portion of the spill was retained onsite; however, some of the spill traversed approximately a third of a mile through a forested area before reaching the mainstem of the Russian River. The Russian River was rising overnight, during the time of the spill, and the river flow exceeded 7,500 cubic feet per second (over 3.3 million gallons per minute) at Hacienda Bridge.

Sonoma Water staff have made the initial required notifications to regulatory agencies and environmental specialists were dispatched to the site to assess impacts, where no effect on aquatic or terrestrial life was observed.

Secondary treated effluent has had the large, inorganic material removed, and much of the organic material has been biologically neutralized. Secondary effluent has flowed through clarifiers to remove solids, but some suspended solids can remain that would be removed in the third, and final stage of the wastewater treatment process.

The Russian River County Sanitation District, which began operations in 1983, serves 3,214 Equivalent Single-Family Dwellings within a 2,700-acre service area. The sanitation facility has a design capacity of 710,000 gallons per day, in average daily dry weather flow, and treats wastewater to tertiary treatment levels (also referred to as advanced water treatment).

Sonoma Water provides water supply, flood protection and sanitation services for portions of Sonoma and Marin counties. Visit us on the Web at www.sonomawater.org