Anaerobic digestion performances of fruit and vegetable waste and kitchen waste

Anaerobic digestion performances of fruit and vegetable waste (FVW) and kitchen waste (KW) were investigated with different mix ratios and organic loading rates (OLR). FVW and KW from campus restaurant were used as feedstocks. Five different mix ratios (0:8, 2:8, 5:8, 8:8 and 8:0) and three OLR(2%, 4%, and 6%(TS)) were used. The results showed that FVW and KW with 5:8 of mix ratio achieved the best performance results with 2% of OLR. The total methane yield was 600 mL/g (TS), which were 5.4% and 10% higher than 4% and 6% of OLR with the same mix ratio, respectively, and which were 4.5%-18% higher than KW with 2%-6% of OLR, and which were 7.1%-510% higher than FVW with 2%-6% of OLR. The anaerobic digestion time was less than 50 days. The peak value of daily biogas yield was 95 mL/g (TS) in the first 20 days. Cumulating propionic acid of VFA and ammonia were avoided effectively at low OLR. Propionic acid of VFA and ammonia affected the stabilities of anaerobic digestion system with increasing OLR and mix ratios of FVW. This study would provide the parameters for effective operation and optimal design of anaerobic digestion facilities of municipal organic solid waste.