Effect of substituting organic fraction of municipal solid waste with fruit and vegetable wastes on anaerobic digestion

Abstract

The potential of replacing fruit and vegetable wastes (FVW) as remarkable sources of environmentally offensive biomass in metropolises with organic fraction of municipal solid waste (OFMSW) on biogas production was investigated. Components of OFMSW as a source separated MSW were prepared in 5 categories of fat and protein, starch, cellulose, fruit, and vegetable waste. Experiments were carried out in four FVW/OFMSW replacement ratios (wet basis) of 0, 15, 30 and 45% at two total solid (TS) concentrations of 8% and 15% at 37 °C. Main results indicated that co-digestion is favorable at lower TS content (8% TS) and higher FVW/OFMSW ratios up to 30%. Although methane yield did not improve significantly for these substitution ratios, the concentration of methane in the biogas enhanced up to 68% and about 92% of volatile solids’ removal achieved. Kinetics study, based on lag phase of Gompetz model, indicated process rapidity increased proportionally to the FVW replacement ratios. Dedication up to 30% of feedstock capacity of ongoing OFMSW biogas plants in metropolises with FVW can suggest more revenue for plants through lowering HRT, increasing biodegradability of substrate, removing undesirable gas and supplying water needed for anaerobic digestion.