Which one of the following statements is NOT correct ?

[amp_mcq option1=”Biomass is a renewable source of energy” option2=”Gobar gas is produced when cow-dung, crop residues, vegetable waste and sewage are allowed to decompose in the absence of oxygen” option3=”Biogas generation reduces soil and water pollution” option4=”Heating capacity of biogas is very low” correct=”option4″]

This question was previously asked in

UPSC NDA-2 – 2020

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Statement D is NOT correct. Biogas primarily consists of methane (about 50-75%) and carbon dioxide (25-50%), with trace amounts of other gases. Methane is a flammable gas with a significant calorific value (heat produced per unit volume/mass when burned). While its calorific value is lower than that of natural gas (which is mostly pure methane), it is comparable to or higher than many other common fuels used in rural areas (like wood or dung cakes) and is sufficient for cooking, heating, and generating electricity, indicating a reasonable heating capacity, not a ‘very low’ one.

– Statement A is correct: Biomass (organic matter) is renewable because it can be replenished relatively quickly through natural processes like plant growth.
– Statement B is correct: Biogas is produced through anaerobic digestion, the decomposition of organic matter by microorganisms in the absence of oxygen. This process is used in biogas plants.
– Statement C is correct: Using organic waste to produce biogas reduces the amount of waste that would otherwise pollute soil and water bodies. The digested slurry (digestate) can also be used as a nutrient-rich fertilizer, replacing chemical fertilizers and improving soil health.

Biogas technology provides a sustainable way to manage organic waste, produce renewable energy, and create organic fertilizer, contributing to a circular economy and reducing greenhouse gas emissions, particularly methane emissions from uncontrolled decomposition.

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