Effect of mixing ratio on biomethane potential of anaerobic co-digestion of fruit and vegetable waste and food waste

Anaerobic digestion (AD) is a mature technology for treating organic fraction of municipal solid waste. In the present study, an attempt has been made to evaluate the optimum mixing ratio for co-digestion of two main streams of organic fraction of municipal solid waste (OFMSW) i.e., fruit and vegetable waste (FVW) with food waste (FW) and its effect on biogas yield using single-stage anaerobic digester. The different ratios selected for the study were (FVW:FW) (1:1, 1:2, 2:1). The results indicated that (FVW:FW) in the ratio (1:2) gave the highest cumulative biogas yield (510.96 mL/g VS) in comparison to (1:1) (472.2 mL/g VS) and (2:1) (420.5 mL/g VS) ratio, whereas monodigestion of FVW and FW gave cumulative biogas yield of 429.16 mL/g VS and 393 mL/g VS, respectively. The co-digestion of FVW and FW contributed to the digester's stability, which improved operation of AD and increased biogas production. The methane content in the digesters was increased from 35 to 67% with the time. The co-digestion of FVW and FW at optimal mix ratio yields 21% higher methane content as compared to monodigestion of FVW. Performance analysis indicated a volatile solid reduction of 72% at the optimum mix ratio.