Design and Testing of a Small-Scale Biogas Digester Using Livestock Waste in Plateau State

This study involves the design, construction, and performance testing of a small-scale biogas digester using cattle and swine waste in Plateau State, North Central Nigeria. Energy poverty is a significant challenge for rural farming communities in Nigeria, where over 60 percent of households lack access to reliable electricity for cooking, lighting, and agro-processing. Livestock waste from the significant cattle and pig farming activities in Plateau State presents a valuable feedstock resource for biogas generation that remains largely unexploited. This study designs a 4 cubic metre fixed-dome biogas digester using locally available materials including concrete blocks, cement, and mild steel fittings. The digester is fed with a slurry of cattle dung and water at a ratio of 1:1 by weight. Performance parameters monitored over a 45-day experiment include daily biogas production volume, methane content, slurry pH, and temperature variation. Findings reveal that the digester achieves stable daily gas production of 1.2 cubic metres after a 15-day start-up period, with methane content averaging 62 percent. The gas output is sufficient to meet cooking energy needs for a household of six for approximately 2.5 hours per day. Digestate analysis shows high nitrogen and phosphorus content, confirming its value as organic fertiliser. The study concludes that small-scale biogas digesters are technically viable for Plateau State farming households. It recommends a state-funded dissemination programme linking biogas adoption with organic fertiliser promotion.

Keywords: biogas digester, livestock waste, renewable energy, Plateau State, rural energy.