ABSTRACT
Non-conventional, easily available energy sources like waste from animals and agricultural residues has attracted the attention of developing and underdeveloped countries due to the energy crisis, which prompted a steep rise in fuel prices. The current disposal practices for agricultural residues have caused widespread environmental concern as they represent hindrance to sustainable development in rural areas as well as to national economies (Sheehan, 2009). Environmental contamination has also necessitated identification of environmentally sound and economically feasible technologies for waste management (Prasad et al., 2007a, b). Anaerobic digestion is a versatile, effective and established method that is being used world-wide for the digestion of different organic wastes and the production of energy in the form of biogas (Verstraete et al., 2005). Organic waste materials of agricultural, industrial and municipal origin can be converted anaerobically into biogas by the action of rumen-derived microorganisms. This technology has the potential to reduce greenhouse gas emissions, because methane as a main constituent of biogas would otherwise be released into the atmosphere, provoking a greenhouse effect that is 21-fold that of the same volume of carbon dioxide. Apart from this, biogas being a cost-effective and environmentally sound energy source helps in improvement of livelihood and promotes sanitation and a healthier household environment in rural areas. Biogas technology also improves rural livelihoods as it is a cleaner fuel than traditional fuels like wood and fossil fuel and can be used for cooking, lighting and heating.
