Estimation of Biogas Production and the Emission Savings from Anaerobic Digestion of Fruit-based Agro-industrial Waste and Agricultural crops residues

In this study, the biomethane potential of five agricultural crop residues (ACRs) (rice straw, vegetable waste, maize straw, coffee husk and oil palm empty fruit bunches (OPEFB)) and five Fruit-Based Agro-Industrial Wastes (FBAIWs) (jackfruit straw, banana, orange, apple and pineapple peel waste) were evaluated. The carbon and energy balance for each waste was also theoretically modelled for two biogas conversion scenarios (anaerobic digestion (AD) with CHP or biogas upgrading). A standard biomethane potential test (BMP) was operated over 30 days at 37 °C. Specific methane potential (SMP) of FBAIWs was generally higher than that of the ACRs, except for vegetable waste. Vegetable waste was identified as having the highest SMP (0.420 m3 kg−1 volatile solids (VS)added). With respect to ACRs, OPEFB and coffee husk had the lowest SMP values of 0.185 and 0.181 m3 kg−1 VSadded, respectively. This was attributed to the higher lignin content of these wastes which can impact on biodegradation and subsequent biogas production. Theoretical estimations showed a positive energy balance for all wastes tested. In terms of exportable energy, apple peel waste was shown to have the highest exportable energy potential. The FBAIWs also exhibited greater emissions savings than ACRs (with the exception of vegetable waste). This study concluded that there is good potential to valorise these wastes using AD and that this could address the challenges of waste management and clean energy provision in Indonesia.