**4.5 Anaerobic digestion**

Anaerobic digestion is process that uses microorganism to breakdown organic biodegradable matter in the absence of oxygen to produce biogas [46]. It is a common technology that has been used in conversion of sugar biomass. It is simple, cheap, and works under low temperature. Its size ranges from small household to large plant. The technology is appropriate in Africa biowaste treatment since it requires small investment, mature technology, and presence of sugar biowastes especially in MSW and animal wastes. Large presence of animal residue in Africa, 25% globe, this technology is the one to be applied in all parts of Africa. Its use in lignocellulosic materials such as forest residue is inappropriate. It also has low kinetics and hence requiring larges reactors and hence investments. The residues after digestion can also be used as farm manure and thus giving it an added advantage.
