Assessing the Suitability of Animal and Food Waste Samples for Biogas Production and Fertilizer Evaluation

Abstract

With increasing concerns over fossil fuel depletion and environmental pollution, research into alternative energy sources has gained significant momentum. Organic wastes, particularly from animals and food, offer a promising substrate for biogas production, providing dual benefits of energy generation and waste reduction. This study evaluates the suitability of food waste, cow regurgitates, and cow dung for biogas production through biodigestion. The objectives were to design a lab-scale biodigester, compare biomethane yields from each waste, and evaluate their effectiveness as fertilizers. The results indicate that all three samples have properties within the acceptable range for digestion. Food waste exhibited the highest methane yield with a daily biogas production of 0.4979 m³/day, corresponding to an energy content of 27,699.45 KJ/day. Cow regurgitates produced 0.2656 m³/day of biogas, yielding an energy content of 14,739.6 KJ/day. Cow dung yielded 0.3213 m³/day of biogas, translating to an energy content of 17,723.65 KJ/day. Microbial analysis indicated the presence of beneficial bacteria and fungi, such as Staphylococcus spp, Proteus vulgaris, Escherichia coli, Enterobacter aerogens, Aspergillus spp, and Mucor spp, which are advantageous for soil conditioning and nutrient cycling. The study highlights the importance of assessing physicochemical properties, nutrient content, and microbial composition to optimise biogas production and explore the potential of organic waste as a sustainable energy source and soil conditioner.