Advancement in biogas production from the solid waste by optimizing the anaerobic digestion

The crisis of fossil fuel and their negative impact on the environment has caused concern among the scientific communities leading them to look around for renewable sources of energy. This review has emphasized the efficient utilization of organic municipal solid waste as well as agriculture waste in an anaerobic digester for the production of biogas as a sustainable renewable energy. Recent advances in biogas production along with previous research work have been discussed to offer a comprehensive synopsis of the accumulated knowledge. This review also elucidates about the design of an anaerobic digester, the prospect of anaerobic digestion and opportunity in new advances in technology. Biogas is one of the most accepted sustainable renewable energy. The characterization, elimination of contaminants, pretreatment, anaerobic digestion in optimum condition and utilization of energy crops enhanced the efficiency of an anaerobic digester. Pretreatment of segregated organic solid waste increased its putrescibility and further biogas production. The optimized parameters in this review were pH, temperature, loading rate, C/N ratio and solid/liquid ratio of the feedstock. The flow rate of the feedstock was optimized according to the available volume of the digester, residence time and the characteristics of the feedstock. The design of an anaerobic digester should be preferably cylindrical in shape, with a diameter ranging from 6 to 40 m, the depth ranging from 7.5 to 15 m and the conical floor having a slope around 15%. A comprehensive reform in technical, economic, and social policies is essential to accomplish a sustainable energy system considering biogas as a future renewable energy. The flowsheet of the biogas and methanol production has been given in Fig. 1.Fig. 1Flowsheet of the biogas and methanol production[graphic not available: see fulltext]