Empirical Investigation of Biogas Production Potential from Co-Digestion of Municipal Solid Waste and Abattoir Waste in Enugu Metropolis

The rapidly expanding volumes of organic municipal solid waste and abattoir effluent generated in Nigerian urban centres represent an underutilised bioenergy resource that, if harnessed through anaerobic co-digestion, could simultaneously address waste management and energy access deficits in secondary cities. This study presents an empirical investigation of the biogas production potential and process performance of anaerobic co-digestion of municipal solid waste and abattoir waste at varying mixture ratios in Enugu metropolis, South East Nigeria. Batch anaerobic digestion experiments were conducted in 20-litre laboratory digesters at mesophilic temperature (37 degrees Celsius) and thermophilic temperature (55 degrees Celsius) using organic fraction of municipal solid waste sourced from Ogbete market and paunch content from Enugu metropolitan abattoir. Co-digestion ratios of organic waste to abattoir waste of 75:25, 50:50, and 25:75 on a volatile solids basis were tested alongside single-substrate controls. Cumulative biogas yield, methane content, pH evolution, and volatile solids reduction were measured over a 45-day digestion period. Maximum cumulative methane yield of 326 mL per gram of volatile solids added was achieved at the 50:50 mixture ratio under thermophilic conditions, representing a 34 percent improvement over organic waste mono-digestion and a 29 percent improvement over abattoir waste alone. Synergistic effects from nutrient balance complementarity between the two feedstocks were confirmed through carbon-to-nitrogen ratio analysis. Keywords: anaerobic co-digestion, biogas, municipal solid waste, abattoir waste, Enugu.