MBSA Biogas Plant

The main part of the design that constitutes the design a plug flow type digester made of a fibre re-enforced PVC bag of 10 m^3 for anaerobic digestion. Inlet and outet connections are made through 110 mm PVC pipes, and the air input is achieved through an aquarium pump that injects air in the bag through a small plastic hose. A plastic valve is also in place to control the air flow in the system and a PV system of 20W supplies electricity for the pump. Additional components like a condensation trap, a flow meter, pressure release system with pressure meter and 3 valves (gas network control), are required. ^{Thesis by Kevin Chapon} 

Specifications:

The flat dimensions of the system are 7 x 2.6 m

Digester dimensions: 2.6m x 7.0 m

Training needs and support provided by MBSA staff.

Unknown.

Testing of biogas input and performance and effectiveness of liquid/ solid separation for use as a fertilizer were conducted in 2011 by Kevin Chapon from AVANS Hogeschool working with MBSA and FACT – these are some of the findings:

• The hydraulic retention time of the system is set at 50 days so the daily input of feedstock is 1/50 of the digester volume.

• Wet mixture represents 6 m³, so the daily input should be 120 liters.

• The supply of the digester started with 35 kg of cattle dung associated to 55 liters of water during the first month. The amount of manure was decreased by 5 kg every two weeks while adding Jatropha press cake to the mixture. After two and a half months, the digester was supplied by 15 kg of manure and 8 kg of Jatropha press cake.

• The average daily biogas production is 2.71 m^3/day.

One of the by-products of the digester is hydrogen sulphide, a colorless, very poisonous, flammable gas with the characteristic foul odor of rotten eggs at a concentration up to 100 ppm. ^{Thesis by Kevin Chapon}