Biogas Production from University Waste: A Case Study at Dilla University, Ethiopia

This study explores the potential of biogas production from organic waste generated at Dilla University, Southern Ethiopia, through anaerobic digestion. Five treatments were formulated using different ratios of cow dung, café leftovers, fruit peels, and human excreta to evaluate the effect of substrate composition on digestion efficiency and biogas generation. Experimental digesters were monitored over a 60-day period, and samples were analyzed for key physical and chemical parameters including total solids (MTS), total suspended solids (MTSS), ash content (MA), and fresh mass (MFS). Results showed that co-digestion significantly improved substrate degradation compared to mono-digestion. Treatment 2 (6% organic waste, 24% cow dung, 7.5% human excreta) demonstrated the highest reduction in solids, indicating efficient microbial activity and favorable biogas conversion. Estimated methane yields, derived from MTSS values, ranged from 0.244 to 0.470 liters, with Treatment 5 exhibiting the highest theoretical output despite lower digestion efficiency. The findings confirm that integrating food-based organic waste with manure and inoculum enhances biogas production and waste stabilization. The study recommends scaling up the optimized treatment in a pilot biogas plant for educational and community demonstration purposes, while incorporating direct gas monitoring tools in future research.