The efficiency of conversion of animal residues could be raised
to 60% by producing biogas through anaerobic digestion. Biogas
systems offer multiple benefits. For cooking and other household
thermal tasks, it is simple and reasonably efficient to use the gas
directly in conventional low-pressure gas burners. Biogas can provide
lighting when used in mantle lamps. The digester effluent adds
economic value by providing valuable fertilizer. It leads to environmental
protection as well as improving sanitary conditions in rural
areas. Biogas plants are widely in operation in China, India, Sudan,
Taiwan, etc. [25,44,45].