Anaerobic co-digestion of dry fallen leaves, fruit/vegetable wastes and cow dung without an active inoculum – A biomethane potential study

Anaerobic digestion of fruit and vegetable wastes (FVW) is a sustainable energy production technology with a low carbon footprint but lacks consistent, productive process performance. Hence, the anaerobic co-digestion (AcoD) of FVW with various lignocellulosic biomass has become necessary. This study investigated AcoD of dry fallen leaves (DFL) and cow dung (CD) with FVW. Twelve combinations were designed, varying the proportion of DFL and FVW, keeping the amount of CD constant at 6 % total solids and 37 °C. The maximum biogas yield of 809 ± 96 mL/g VSinput was achieved in the reactor with a DFL to FVW ratio of 100:0. In contrast, a maximum methane yield of 388 ± 131 mL/g VSinput was observed in a reactor with a DFL to FVW ratio of 40:60, also saving 2 % (%w/w) of extra water than the former. The proposed co-digestion strategy has the potential for full-scale applications with its positive attributes.