4.2.5. Biomethane

Methane is another gas produced from anaerobic digestion of wastewater and e ffluent. Methane can be produced either by hydrogenophilic-methanogenesis (abiotically) or by fermentation of organic matter present in wastewater (biologically) [76]. Anaerobic digestion process is more proficient over aerobic process for production of methane due to low energy rations, high energy production in the form of methane, and low sludge production with high organic ejection rates. Various wastewater effluents, i.e., PWW, brown water, rejected water and seed sludge, sugarcane juice in the e ffluent discharged from sugarcane industry, etc., have been used for methane production [22,55,77].
