Potentiality of fruit and vegetable waste by anaerobic co-digestion with municipal sewage sludge and biogas yield

Abstract

The co-digestion process for the treatment of two or more organic biodegradable waste streams by anaerobic digestion offers great potential for the proper disposal of solid waste. The anaerobic co-digestion of fruit and vegetable waste (FVW) and municipal sewage sludge (MSS) was investigated under mesophilic conditions and compared with the separate digestion of the substrates. The continuous studies were performed at an organic loading rate of 1.5?g VS/l.day and at an HRT of 20 days. It was observed that FVW had better performance than the MSS. However, FVW addition led to improvement of the process stability, with low Volatile Fatty Acids (VFA)/Total Alkalinity (TA) ratio and improves the gas production yield with its co-substrates. Specific gas production values of three reactors were: (i) 0.49 l/g VSin & 1.0 l/g VSdes for FVW, (ii) 0.261 l/g VSin & 0.643 l/g VSdes for MSS and (iii) 0.613 l/g VSin & 1.078 l/g VSdes for co-digestion of FVW and MSS. Co-digestion is proven to produce more biogas.