Waste Water Treatment Plant Operations

The Waste Water Treatment Plant, operational since 1958, serves the City of Ukiah and the Ukiah Valley Sanitation District.  It has a current treatment capacity of 2.8 million gallons per day (MGD) of dry weather flow and 20 MGD of peak wet weather flow.  Primary treatment removes floating material, oils and greases, sand and silt and organic solids heavy enough to settle in water.  Secondary treatment biologically removes most of the suspended and dissolved organic material.

Treatment steps are grit removal, primary sedimentation, secondary treatment (trickling filters), secondary sedimentation, final clarification (advanced waste water treatment facility), sludge digestion (digesters), disinfection, dechlorination, and effluent discharge to the percolation  ponds.

The Waste Water Treatment Plant underwent a three year, $56.5M improvement project that was completed in 2009. This plant will insure continued compliance with permit requirements and meet future demand growth.