Anaerobic digestion is a bio-chemical technology used for the treatment of organic wastes and the production of biogas, which can be used as a fuel for heating or co-generation of electricity and heat [1]. Bio-gas has globally remained a renewable energy source derived from plants that use solar energy during the process of photosynthesis. Being a source of renewable natural gas, it has been adopted as one of the best alternatives for fossil fuels after 1970’s world energy crisis. Bio-gas is a colourless, flammable gas produced via anaerobic digestion of animal, plant, human, industrial and municipal wastes amongst others, to give mainly methane (50-70%), carbon dioxide (20-40%) and traces of other gases such as nitrogen, hydrogen, ammonia, hydrogen sulphide, water vapour etc. [2]. Bio-gas production is mainly based on the bio-chemical process.