Question

Explain biogas plant with a labelled diagram.

Answer 1

• Biogas or gobar gas is a combustible gas.
• It is produced through the anaerobic breakdown of waste biomass.
• The biogas plant consists of the following parts:-

1) Inlet or charge pit:- for passage of slurry into the digester.
The raw material used is cattle dung, farm refuse, organic waste.

2) Digester:- cylindrical tank which is airtight, above which is present a floating gas holder of metal with an outlet of gas and pit for removal of sludge.

• Here the organic wastes get solubilized into simpler substances called monomers (solubilisation).
• Monomers change to organic acid by fermenting microbes (acidogenesis).
• Organic acid mostly formed is acetic acid.
• Methanogens become active and act on components of microbial digestion and form methane gas (methanogenesis).

3) Outlet:- consists of sludge which is used as manure.

• The methane gas formed in this process is used for cooking and lighting.