Construction of a pilot scale biogas digester at the University of Ibadan Dairy Farm, Abadina

The quest for cleaner energy sources and renewable energy has become a drive force in the current energy market, creating a gradual shift from total dependence on fossil fuel. Production of biogas through the anaerobic digestion of organic wastes provides an alternative for energy supply, recovery and waste treatment. The University of Ibadan Dairy Farm, Abadina has a digester which was abandoned due to its inefficiencies. The digester has been modified a couple of times over the years without yielding any biogas, hence, the need for a functional digester.

A modified Gobar design was adopted in the construction of a new digester. An agitator was introduced in the design for stirring of the slurry. The designed digester was a plant capacity of 4m³ with a retention time of 35 days. The existing digester was demolished and the new digester was erected in its stead. The entire plant was made of reinforced concrete. The digester was loaded with 180 kg of dung daily, with a mix ratio (dung to water) of 1:1.

A 2 m³ gas bag was connected to the gas outlet for collection of the produced gas. Gas production started after the 7th day of loading the digester with substrate. The collected gas was tested for burnability. The initial burn test quenched the flame and the digester was allowed for a week without feeding. The biogas burnt with a blue flame during the second test. A biogas cooking stove was made available to enable utilization of the produced gas.