Daily and Cumulative Biogas Yields from Selected Animal Dungs

In this study, the production of biogas from three common animal waste namely cow dung, poultry droppings and swine dung was evaluated. This was done by assessing the daily and cumulative biogas yields from the three selected feedstocks. Plastic 12-l capacity batch-fed digesters were employed in this study. 4.8 kg of waste was used for all substrates digested. The waste was mixed with water to form slurry in a ratio of one part of waste to one part of water by volume to arrive at a substrate input of 0.0096m³/digester. Each reactor was connected via its gas outlet to a tyre tube used as the gas collecting apparatus. The volume of biogas yield was measured and recorded on a daily basis using a digital weighing scale. Poultry droppings had the highest cumulative volume of biogas production of 0.1741 m³ (0.0363 m³/kg), while cow dung and swine dung, respectively, produced 0.1020 m³ (0.0213 m³/kg) and 0.0670 m³ (0.0028 m³/kg) of biogas. The respective digestion of cow dung and poultry droppings and swine dung recorded average daily gas production of 0.0058 m³, 0.0034 m³ and 0.0022 m³, respectively. The anaerobic digestion process shows that poultry dung is one of the best feedstock for biogas production with its production profiles exceeding the production from the other two conventional feedstocks (cow dung and swine dung).