From Grease to Gas: Anaerobic Digestion of Fats, Oils, and Grease (FOG) at the Hyperion Treatment Plant

Anaerobic digestion of high-strength organic wastes, such as Fats, Oils, and Grease (FOG) has become increasingly popular among wastewater treatment facilities in Southern California [1]. In 2010, the City of Los Angeles’ Hyperion Treatment Plant started running its own FOG Digestion Pilot Project. The project injects processed grease trap wastewater (FOG) into one of 16 anaerobic digesters at the facility. A partnership was formed between the Hyperion Treatment Plant (HTP) and Baker Commodities, Inc., a Grease rendering company located in the City of Vernon. They provide processed grease trap wastewater (FOG) to the pilot project. The plan was to load the digester with increasing amounts of FOG and observe the impact. The parameters monitored in the digester during the test are volatile acids, pH, alkalinity, temperature, and gas production in the digester. The pilot project’s objective was to obtain a 10 to 20% increase in gas production. So far those expectations have been exceeded.