Co-digestion of poultry droppings and banana waste for maximizing biogas production in Bangladesh

Abstract

Poultry industry is a promising sector for meeting protein demands in Bangladesh. Poultry droppings generated from farms pose a threat to the environment, but could be one of the best sources of plentiful substrates for anaerobic co-digestion. Poultry droppings mixed with carbon rich banana waste, which is readily available in Bangladesh, can be used for increasing biogas production. Hence, a study was conducted to assess the bio-methane potential from the anaerobic co-digestion of poultry droppings (PD) with raw banana peel (BP), and to find the optimal mixing ratio. The batch study was conducted in an incubator at 35 °C for a retention time of 83 days. The PD and BP were mixed at a ratio of 100:0, 90:10, 70:30, 50:50, 30:70,10:90 and 0:100 to find out the optimum one. Five kinetic models were used to fit the experimental result to determine different kinetic parameters. The highest amount of biogas (347.0 ± 53.6 ml/gVS) and methane (200.1 ± 18.6 ml/gVS) were obtained at 50:50 ratio of PD and BP for the digestion period. The biogas and methane yield at this ratio were 1.68 and 3.12 times higher than the mono-digestion of banana peel, respectively. Biogas production was not significant when compared with mono-digestion of PD, but co-digestion at 50:50 ratio showed maximum usability of banana peel. Furthermore, the results of kinetic modelling showed both the cone model and the modified Gompertz model are best fitted for predicting methane production.