BIOGAS DIGESTER USING COW DUNG AS A SUBSTRATE

Biogas can be a solution to South Africa energy needs especially to rural areas of Eastern Cape Province that have plenty of biogas substrates from cattle, donkeys, goats, sheep and chicken. The effectiveness of cow dung for biogas production was investigated using a field batch biogas digester. The cow dung was collected from University of Fort Hare Dairy farm and was analyzed for total solids, volatile solids, total alkalinity, calorific value, total alkalinity, pH, Chemical Oxygen Demand and Ammonium Nitrogen. The biogas composition was analysed using a Gas Analyzer. In the experiment, it was observed that the biogas production from the cow dung increased exponentially with time and ceased after certain days of degradation. The alkalinity values were within the normal range, above the threshold alkalinity of 500 mg/L for anaerobic digestion and stable ammonium-nitrogen levels in cow dung improved anaerobic digestion process. The study revealed that cow dung produced biogas yield with an average methane yield of 50%. In addition, the study revealed further that cow dung as an animal waste has great potentials for generation of biogas and its use should be encouraged due to its early retention time and high volume of biogas yields