Experimental Investigation of Biogas Yielding Rate from Anaerobic Co-Digestion of Multiple Organic Feedstocks Using a Bio-digester

Abstract

Background: The high cost of fossil fuels has driven the exploration of renewable energy alternatives. This study investigates the anaerobic co-digestion of waterleaf, cow dung, and food waste to optimize biogas production. Methods: Four co-digestion experiments were performed using a prototype plastic bio-digester over 50 days. The combinations tested were: waterleaf with cow dung, waterleaf with food waste, food waste with cow dung, and a mix of all three feedstocks. Results: Co-digestion of waterleaf and food waste yielded an average biogas output of 25%, with a pH of 7.2 and a carbon-to-nitrogen (C/N) ratio of 28. Combining waterleaf and cow dung produced a 31% yield, a pH of 7.2, and a C/N ratio of 29. The mixture of food waste and cow dung resulted in a 34% biogas yield, with a pH of 7.1 and a C/N ratio of 30. The highest yield, 46%, was achieved by co-digesting waterleaf, cow dung, and food waste, with a pH of 7 and a C/N ratio of 32. All feedstock combinations maintained neutral pH levels, benefiting from the unique properties of each component: waterleaf provided vitamins A and C, food waste supplied carbohydrates and proteins, and cow dung contributed anaerobic microbes essential for digestion. Additionally, temperature was a significant factor influencing biogas production. Conclusion: Co-digesting waterleaf, cow dung, and food waste maximized biogas production, demonstrating the potential for enhanced renewable energy generation through optimized anaerobic digestion processes.