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Examoogle • User • info@examoogle.com • EE-2024-8821
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The main source of production of biogas is
Human waste
Wet cow dung
Wet livestock waste
All of the above
All of the above
Quick Summary: Biogas is produced through the anaerobic digestion of organic materials, including animal excreta, human waste, and agricultural residues. All listed options represent high-quality feedstocks rich in biodegradable organic matter suitable for methanogenic bacterial activity.
Biogas is produced through the anaerobic digestion of organic materials, including animal excreta, human waste, and agricultural residues. All listed options represent high-quality feedstocks rich in biodegradable organic matter suitable for methanogenic bacterial activity.
CnHaOb+(n−4a−2b)H2O→(2n+8a−4b)CH4+(2n−8a+4b)CO2 — General stoichiometry for methane production
Biogas production occurs in a digester tank where anaerobic bacteria break down organic complex polymers into smaller molecules like acetic acid, H2, and CO2. These are then converted into methane (CH4) and carbon dioxide (CO2) by methanogenic archaea. The process occurs in four stages: hydrolysis, acidogenesis, acetogenesis, and methanogenesis.
Biogas typically contains 50-70% methane (CH4), 30-50% carbon dioxide (CO2), and trace amounts of H2S.
Methanogenesis is highly sensitive to pH, temperature, and the carbon-to-nitrogen (C/N) ratio of the feedstock.
Optimal C/N ratio for effective anaerobic digestion is typically between 20:1 and 30:1.
Reduces greenhouse gas emissions by capturing methane.
Provides high-quality organic fertilizer as a byproduct (digestate).
Offers a sustainable solution for waste management.
Lower energy density compared to natural gas.
Potential for hydrogen sulfide (H2S) corrosion in combustion equipment.
Biological processes are sensitive to environmental fluctuations.
Cooking and heating in rural households.
Electricity generation via biogas-powered internal combustion engines.
Production of Compressed Biogas (CBG) for automotive fuel.
Human, cow, and other livestock waste are excellent sources because they contain large populations of methanogenic bacteria required to initiate the breakdown process.
The process is often referred to as 'Bio-methanation'.
D is correct — Human waste, cow dung, and general livestock waste are all rich organic substrates that sustain the anaerobic microorganisms necessary for biogas production.
In competitive exams, remember that any biodegradable waste (kitchen waste, agricultural residues, sewage) qualifies as a biogas feedstock. The key factor is the availability of organic carbon and the absence of oxygen.