Electricity and biogas production in portable biodigester-microbial fuel cells: Optimum substrate composition and ratio from organic waste

Organic waste comes from various sources, such as food or vegetable waste and animal manurequickly decomposes in nature, but it significantly impacts the environment and human health, with methane (CH 4 ) and carbon dioxide (CO 2 ) from organic waste contributing to global warming, and further harming the environment.This study aims to determine the optimal substrate composition of organic waste from vegetable and cow manure for generating electricity using an integrated anaerobic digestion (AD) and microbial fuel cells (MFCs) system.The experiment used portable biodigester-MFCs systems for households and was conducted for eight weeks.Four biodigester reactors using different ratios of vegetable waste to cow manure were applied: R1 (100%:0%), R2 (75%:25%), R3 (50%:50%), and R4 (0%:100%).The result shows the highest electrical voltage in the third reactor (R3), registering at 0.62 mV, consisting of 50% cow manure and 50% vegetable waste.The highest biogas yield (13,192 ml) comes from the second reactor (R2), with a composition of 25% cow manure and 75% vegetable waste.The addition of cow manure to vegetable waste enhanced electricity production through CH 4 production in an anaerobic digestion process.Based on the above result, substrate composition and ratios are needed to influence the optimum pH and temperature to optimise the metabolic activity of bacteria in portable MFCs efficiently.Among the four biodigester tested, R2, with a 75% vegetable waste to 25% cow manure ratio, achieved the highest biogas yield of 13.192 ml and highest CH 4 content.Conversely, R4, comprising 100% cow manure, produced the smallest biogas volume but achieved the highest CH 4 .These findings highlight the significant role of cow manure in biogas production and the challenges of utilising vegetable and organic waste effectively.