Biogas is a mixture of gases containing 50 to 75% methane which is burned as a cooking fuel and lighting. It is captured during decomposition of organic materials like animal fecal matter, dung and municipal waste in an oxygen-free environment. After the bacteria have fed on the organic waste, the residue is nitrogen rich fertilizer used for increasing crop yields. Biogas is a combustible gas produced by decay of organic materials, such as manure, agricultural residues or human feaces, in an oxygen-free environment. A digester is a sealed tank where biogas is formed. It has a feeding point, gas storage chamber and effluent exit. The biogas can be burned as a fuel. The effluent can be applied directly to fields, or can be composted to provide a solid organic fertilizer.
Raw materials and technology
Organic waste: Cow manure , feacal matter, food left overs, urine (human and animal)
Storage and conversion
8 cubic meter digester to a 200 cubic meter digester.
40,600 cubic meters of biogas per year
Information for consumers
Quantity used per meal
500L per meal per day
Schools, Hospitals, Markets households, restuarants, hotels, tourist lodges, Hospital, School
Typical foods cooked with this fuel
Posho, Beans, Millet bread, Soy beans,Meat stew, Berbecue, Cassava, Sweet potatoes, Ground nuts,
Biogas digester description: Fixed dome digesters are built on a circular concrete base using clay bricks. The sides curve inwards to form a dome where the biogas collects and is stored. The outer walls of the digester are protected by plastering the outside walls. A neck is built onto the dome which is sealed by a cover to prevent gas leakage. This cover can be removed to conduct maintenance on the digester. The digester is plastered inside with water-proof cement to make it gas-tight and to prevent leakage of effluent. The outside of the dome is well plastered and the excavation site back-filled with soil and then landscaped. The continuous input of organic waste and the biogas pressure will push the effluent out of the Biogas-Digester into the Expansion Chamber. Some of the Bio-Slurry in the expansion chamber will move back into the digester for further digestion to optimize biogas production. The rest will flow into the Slurry Storage Tank, where it can be stored safely and used when needed. The gas will be tapped from the neck of the digester and piped underground to the milk pasteurization unit and kitchen, which is a couple of meters away from the digester site.
Vianney Thesis - Chapter 2