DESIGN AND FABRICATION OF A PLASTIC BIOGAS DIGESTER FOR PRODUCTION OF BIOGAS IN BENUE STATE, NIGERIA

Access to clean and affordable energy remains a major challenge in Nigeria, particularly in rural, agriculture-dependent states such as Benue, where households largely rely on firewood, charcoal, and kerosene for cooking. This study focuses on the design, fabrication, and performance evaluation of a low-cost plastic biogas digester for sustainable biogas production using locally available agricultural waste. A high-density polyethylene (HDPE) plastic digester with a working volume of 200 L (scaled to 2 m³ for household application) was designed and installed at the Department of Agricultural Education, Joseph Sarwuan Tarka University, Makurdi. The digester was fed with a co-digestion mixture of poultry droppings and cow dung at a 1:1 waste-to-water ratio to maintain suitable total solids concentration for anaerobic digestion. Biogas production was monitored over a 25-day hydraulic retention period, alongside assessment of structural integrity, gas purification efficiency, and usability for household cooking. Results showed that biogas production commenced within a few days of startup, peaked between days 12 and 17, and yielded a total of approximately 3.80 m³ of biogas. Combustion tests confirmed the suitability of the gas for cooking. The plastic digester performed efficiently without leakage or structural failure, while the gas purification system effectively reduced moisture and hydrogen sulfide. The study demonstrates that plastic biogas digesters are a viable, low-cost, and user-friendly alternative to conventional systems, offering significant benefits for renewable energy generation, waste management, environmental protection, and improved living standards in Benue State and similar rural settings.