Biosolids Beneficial Use Program
Committed to Responsible and Economical Use of Our Natural Resources
Before the Biosolids Beneficial Use Program was introduced at the Laguna Treatment Plant in 1985, all the solids that passed through the plant went to the Sonoma County landfill. By 1997, only a third of the biosolids material was sent to landfill. The remaining two-thirds were used in land application, as fertilizer or produced into organically-based compost*. Currently, with stepped up land application and composting programs, only five percent of the biosolids generated at Santa Rosa’s Regional Water Reuse Plant reach the landfill, where it is used as alternative daily cover.
Biosolids Value Chain (BVC)
The City of Santa Rosa Biosolids Value Chain (BVC) is a system unique to the Water Reuse Plant. The diagram below shows the flow of wastewater into the collections system, and the steps leading to biosolids end use. The treatment process begins before the wastewater reaches the treatment facility. Industrial facilities are required to pre-treat their wastewater to remove contaminants before discharging into the public wastewater system. Once the wastewater enters the plant through the collection system, solids and liquids are separated. The solids go through the steps shown below in the BVC and are turned into Class B biosolids, the organic product of wastewater treatment, a never ending resource.
Biosolids Beneficial Use Options
CompostingTurning biosolids into compost is a more involved and expensive process than land application, but the end product is marketable, and its use is approved by the EPA for gardening and landscape application in places such as parks,
LystekIn 2016 the City of Santa Rosa started working with Lystek International, Inc. to process some of the biosolids produced at Santa Rosa’s Water Reuse Plant. Biosolids are sent to the Lystek Organic Material Recovery Center at the Fairfield Suisun Sewer District.
A byproduct of treating and processing biosolids is methane gas. At the City's Laguna Treatment Plant, this gas is used to generate about thirty percent of the Plant's energy needs.