Comparative Analysis of a Locally Developed Biogas Digester Using Selected Substrates

A work on the comparative analysis of selected substrates for biogas production using a developed digester is presented. The substrates utilized include cow dung and vegetable waste. The developed digester has 60 litres of substrate volume, incorporates ease of stirring the slurry and mobility of the digester within the farm. The digester was charged with cow dung and vegetable waste respectively with water in a ratio 1:2 at a mesophilic temperature range (20°C – 45 °C) for thirty days retention time and comparative yield within the same operating conditions was studied. The results obtained from the gas production showed that cow dung produced a cumulative biogas yield of 0.702 litres while vegetable waste produced a cumulative yield of 0.144 litres. This result showed that these wastes could be a source of renewable gas if operated on a large scale, while simultaneously reducing environmental pollution particularly within a farm. Also, the results highlight the selection options available to a rural farmer in terms of yield.