Effect of Retention Time on Biogas Production from Poultry Droppings and Cassava Peels
A study was carried out on different retention times in the anaerobic fermentation of slurry from poultry droppings and cassava peels. The system adopted in this work was batch-type. Daily gas production fell slightly from 130 to 32 litres as retention time was increased from 10 to 40 days for poultry droppings. For cassava peels the daily gas production fell slightly from 30 to 15 litres as retention time was increased from 5 to 75 days. The amount of gas produced per unit of volatile substrate charged into a polyethylene digester showed a linear increase with retention time. The total biogas produced from poultry and cassava wastes was 1.508m3 and 1.179m3 for 42 days and 79 days respectively. The ambient and slurry temperature for poultry and cassava were (33.6oC, 33.0oC) and (29.4oC, 35.6oC) which are under mesophilic temperature.
Key word: Batch-type, Anaerobic, Substrate, Volatile, Polyethylene.