Following are the factors affecting methane production:
Proper solubilisation of organic materials (the ratio between solid and water) should be 1:1 when it is house hold type.
In the beginning, seeding of slurry with small amount of sludge of another digester activates methane evolution. Sludge contains acetogenic and methanogenic bacteria.
For the production of sufficient amount of methane, optimum pH of digester should be maintained between pH 6-8 as the acidic medium lowers down methane formation.
Fluctuation in temperature reduces methane formation, because of inhibition in growth of methanogens. In case of mesophilic digestion, temperature should be between 30°C and 40°C but in case of thermophilic ones, it should be between 50 and 60°C.
5. Carbon-nitrogen (C: N) ratio:
Improper C: N ratio lowers methane production. Maximum digestion occurs when C: N ratio is 30: 1. Amendment of nitrogen or carbon substrates should be done exogenously according to chemical nature of substrate.
6. Creation of anaerobic conditions:
It is obvious that methane production takes place in strictly anaerobic condition; therefore, the digesters should be totally air tight. In Indian conditions, digesters are burried in soil.
7. Addition of algae:
Ramamoorthy and Sulochna (1989) have found an enhancement in biogas production on addition of algae, Zygogonium species. The amount of biogas produced from the algae was twice (344 ml/g dry algae) in comparison to cow dung (179 ml per g dry cow dung). Therefore, addition of algae holds promise to get biogas in sufficient amount.