Factors Controlling Stable Anaerobic Digestion of Food Waste and FOG

Fifteen food waste and one grease trap waste samples from the U.S. Air Force Academy were evaluated for anaerobic digestion. Biochemical methane potential per unit of chemical oxygen demand fed was observed to be related to the fat-plus-protein content. Stable digestion of wastes was possible in a stand-alone configuration at rates of 10 g-COD L−1 d−1 provided that adequate acclimation measures were taken. Trace metal nutrient supplementation and feeding the digesters with more than 10% solids were also critical. A new concept of the specific energy loading rate (SELR) is proposed. The intent is to address the wide variety and energy-contents of codigestion feed stocks. SELR showed promise for evaluating of the loading of digester feed stocks. These results of this research support the implementation of food waste digestion as a means of decreasing loading to landfills, decreasing methane greenhouse gas emissions from landfills, and increasing energy sustainability.