The Use of Solid Fuel for Biogas Production in a Biodigester

Abstract

Biogas production technology is a technology with great potential and has the potential to influence the type of energy mix available within a given community. Biogas was produced by the microbial digestion of organic matter in the absence of air in a bio digester. Cow dung was used as the solid fuel necessary for biogas production. Approximately 40kg of cow dung was collected for the purpose of this study. The cow dung collected were sun dried and crushed manually to ensure homogeneity before mixing with water to produce biogas by anaerobic decomposition. Cow dung and water were mixed in the ratio 2:1. The mixture was homogenized with manual stirrer. A digester of 400 liters' capacity was designed and the inner part of the digester was covered with nylon to ensure proper cow dung fermentation. A plastic pipe situated at the top was connected to the digester to serve as gas outlet of the digester and the other end of the plastic pipe was connected to an inflatable tube for gas storage. The digester was stirred three times a day to avoid scum formation in the digester. There was less biogas produced at the initial days. The minimal production of biogas at the initial three days was mainly due to the slow microbial growth. There was a substantial increase in biogas production from the 9th day. The increase in biogas production was due to the exponential growth of microbial activity in the digester. Sudden decreases in biogas production was due to unregulated pH. in the digester. The unregulated pH in the digester increased the concentration of ammonia nitrate. Ammonia nitrate can inhibit the process of biogas production.