What is biogas
Biogas is a methane rich flammable gas that results from the decomposition of organic waste materialBiogas is produced by anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material and energy crops. Biogas also called as ‘Marsh gas’
Biogas is a type of biofuel.
This type of biogas comprises primarily methane and carbon dioxide
Composition of biogas
• Biogas is generated by the activity of anaerobic bacteria
• Composition depends on: the composition of raw material,
organic loading to digesters, time and temperature of
anaerobic digestion.
Composition of biogas
Substances Symbol Percentage
Methane CH4 50 - 70
Carbon Dioxide CO2 30 - 40
Hydrogen H2 5 - 10Nitrogen N2 1 - 2
Water vapour H2O 0.3
Hydrogen Sulphide H2S Traces
Advantages of biogas
• Production of large amount of methane gas (ambient temperature storage)
• Production of free flowing thick sludge
• Odourless sludge
• Sludge can be used as fertilizer and soil conditioner
• Sanitary way for human and animal waste disposal
• Conservation of scarce resources like wood
Disadvantages
Explosion chances
• High capital lost
• Incorrect handling of liquid sludge causes pollution
• Requires control and maintenance
• Needs proper condition
• Use as a fuel requires removal of CO2 and H2S
Factors affecting yield and production of biogas Many factors affecting the fermentation process of organic substances under anaerobic condition are,
The quantity and nature of organic matter
The temperature
Acidity and alkanity (PH value) of substrate
The flow and dilution of material
