Assessment of Biogas Production Potential from Agricultural Waste in Benue State

Agricultural biomass represents an underutilised feedstock for biogas production in Nigeria's food belt, particularly in Benue State where large volumes of crop residues and animal manure are generated annually. This study assesses the biogas production potential of selected agricultural waste streams in Benue State, including cassava peels, yam stems, poultry manure, and cattle dung from farming communities in Makurdi, Gboko, and Otukpo Local Government Areas. The research employs a laboratory experimental methodology, conducting batch anaerobic digestion tests on individual and co-digested substrate combinations. Biogas yields, methane content percentages, and volatile solid reduction rates are measured over a 30-day retention period using water displacement biogas measurement units. The study further performs a geographic resource mapping exercise to estimate total theoretical biogas potential from available agricultural waste in the three study LGAs. Findings indicate that co-digestion of poultry manure and cassava peels produces the highest methane yield, reaching 320 mL CH4 per gram of volatile solids, exceeding single-substrate digestion by up to 45 percent. The study calculates that the assessed agricultural waste streams in Benue State could theoretically supply biogas equivalent to the annual cooking energy needs of over 120,000 rural households. Recommendations include pilot-scale community biogas digesters, farmer cooperative involvement in feedstock supply chains, and integration with state renewable energy programmes. Keywords: biogas, agricultural waste, anaerobic digestion, Benue State, rural energy.