Influence of Nitrogen Content in Food Waste on Biogas Production

Abstract

AbstractHigh carbon content and high‐level biodegradability are major constraints of the anaerobic digestion of food waste. In the present study, anaerobic digestion of model food waste was carried out in a fed batch digester. Nitrogen content in model food waste was adjusted by the addition of ammonium chloride at the desired C/N ratio. Biogas production at ammonium chloride percentages of 0, 0.8, 1.5, 2.14, and 3.2 % (weight basis) were carried out under mesophilic conditions in a pilot plant scale floating drum digester. At an ammonium chloride percentage of 1.5 % that balances C/N ratio 25, highest biogas production of 0.42 m3 kg−1 of VS was attained while biogas production from food waste without ammonium chloride of 0.06 m3 kg−1 of VS was obtained. The highest methane yield of 0.323 m3 kg−1 of VS was found at ammonium chloride of 1.5 % while methane yield of 0.042 m3 kg−1 of VS was achieved from food waste without ammonium chloride. The highest percent increase CH4 yield of 669 % was obtained at an ammonium chloride percentage of 1.5 %. Biogas productivity obtained at ammonium chloride percentage of 1.5 % was 0.6 L L−1 d−1. Hence, the optimum ammonium chloride percentage obtained was 1.5 % which balances the C/N ratio at 25.