Implementation of a FOG Co-Digestion Program at the City of Santa Barbara

The City of Santa Barbara Public Works Department has initiated a program to enhance digester gas production through the introduction of fats, oils and grease (FOG) into the two anaerobic digesters at El Estero Wastewater Treatment Plant (WWTP). The anaerobic digesters produce biogas as a by-product of the treatment process, which is used to heat the digesters and to generate electricity using two onsite fuel cells.The paper will report on regulatory requirements on the local and state level, challenges encountered, and decisions made during the design process, and the City's unique approach of teaming with a local grease hauler to minimize city staff's involvement in storing and pre-processing grease, while benefitting the City and the local community. A future pilot study will evaluate the City's experience of FOG receiving, co-digestion, and the actual increase in the amount of biogas produced.