Volatile fatty acids production from food wastes and its application to biological nutrient removal

Korean food wastes were anaerobically digested to produce volatile fatty ac ids (VFA) that can be used as a carbon source in biological nutrient remova l in a sequential batch reactor (SBR). Acetate, propionate and butyrate wer e produced at a yield of 379-400 g VFA/kg VS0 (initial volatile solids). Th e ratio of SCOD (Soluble Chemical Oxygen Demand) of VFA to ammonia nitrogen (N) was in the range of 36.2-36.5 and the ratio of SCOD to phosphorus was between 151 and 162. The removal rate of nitrogen and phosphorus improved f rom 44% and 37% to 92% and 73%, respectively when the VFA were added to the influent of the Taejon municipal wastewater plant. The concentration of ni trogen and phosphorus were maintained below 3 mg/l and 1 mg/l, respectively . The N- and P-content of the food waste was low enough not to influence th e final N- and P-concentrations of the wastewater.