What is the role of methanogens in the anaerobic sludge during sewage treatment?

Step-by-step solution

Microbes produce different types of gaseous end-products during growth and metabolism. The type of the gas produced depends upon the microbes and the organic substrates they utilise. In the examples cited in relation to fermentation of dough, cheese making and production of beverages, the main gas produced was CO2. However, certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with CO2 and H2 . These bacteria are collectively called methanogens, and one such common