Biogas Yields from Anaerobic Digestion of Pre-consumer and Industrial Food Waste and Solids Management at Inland BioEnergy

The Inland BioEnergy (IBE) food waste digester facility located in Chino, California has been in operation since 2012. IBE is one of the largest dedicated food waste digester systems in the State of California. The two anaerobic digesters onsite are currently processing up to 272 wet metric tons (300 wet tons) per day and the plant’s permitted capacity is 545 metric tons (600 wet tons) per day. Digester feedstock sources include industrial food processors and pre-consumer food waste from grocery markets, pre-processed at a material recovery facility. The purpose of this paper is to introduce California’s first dedicated food waste digestion project, share lessons learned, and present biogas yields of various substrates. Bench-scale biogas yield tests are performed prior to feeding the blend of these substrates to the full-scale digester. Biogas yields are used to determine sustainable feed rates to ensure long-term operational stability of the digesters. For Solids Management the recovered fiber and seeds from food waste pre-screening was used for animal feeding or composting. The centrifuge cake from digestate dewatering was sent to a nearby composting plant.