The septic odor at Pleasant Valley Road and Highway 20 should go away by April because of the installation of a biofilter media, an odor-control mechanism used successfully by many municipalities.
The noxious smell, a persistent issue at this intersection, is coming from pipes installed in 2019 that carry effluent from septic tanks to the Lake Wildwood Wastewater Treatment Plant. The offender is hydrogen sulfide, a gas produced by bacteria in the wastewater flow.
“We do recognize it as a major issue,” said Trisha Tillotson, director of the Nevada County Community Development Agency. “The problem is amplified by the location sitting at the stoplight.”
The original odor control system in the problem area experienced component failures (oxygen generator, cycle pump, oxygen sensors) that made the equipment ineffective. The county next entered a pilot program that added chemicals to inhibit the offending bacteria’s growth, but that did not deliver the desired results of eliminating the smell.
County officials believe the new project and approach will finally provide a long-term solution that will correct the problem. District staff will install two vaults, one on both sides of Highway 20, that will house the biofilter media. Pipes will then carry the foul air and dissipate it under the media in the vaults.