Does the Addition of High Strength Wastes Affect Biosolids Quality?

San Francisco Water, Power, Sewer, the municipal agency charged with collecting and treating San Francisco's wastewater, has been conducting demonstration activities for a Fats, Oils, and Grease (FOG) to Biodiesel pilot at the City's Oceanside Water Pollution Control Plant (OSP). This project allows for the feeding of filtered trap waste or refined waste streams, such as brown grease directly to the OSP mesophilic anaerobic digesters. Since approximately 40% of OSP's Class B biosolids are reused in land application sites around the San Francisco Bay Area, the addition of new streams into the plant must not compromise the biosolids reuse program. The Project Team set out to collect and analyze data from the new FOG waste stream to evaluate any potential impacts of this addition to final biosolids quality.