Read the steps in the working of a gobar gas plant:
(A) Cattle dung is fed to the plant.
(B) Gas is produced and used as fuel.
(C) ________________
(D) It is used as an organic fertiliser and soil conditioner.
Which of the following fills the missing step (C)?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → The slurry that is left over is taken out
In a gobar gas plant, cattle dung gives gas for fuel. What is left behind is a slurry, and this slurry is the organic fertiliser of step (D).
Option (1) Earthworms turn the gas into compost — Incorrect. Earthworms turn organic matter into compost; gas cannot become compost.
Option (2) Methane escapes into the atmosphere — Incorrect. The gas is used as fuel; letting it escape would give no fertiliser for step (D).
Option (3) The ash from burning the gas is collected — Incorrect. Burning gas leaves no ash; the fertiliser is the slurry.
Option (4) The slurry that is left over is taken out — Correct. The slurry becomes the fertiliser in step (D).
NCERT (2026-27): “7.5 Strategies for Sustainable Development … To rectify the situation, subsidised LPG is being provided. In addition, gobar gas plants are being provided through easy loans and subsidy. As far as liquefied petroleum gas (LPG) is concerned, it is a clean fuel — it reduces household pollution to a large extent. Also, energy wastage is minimised. For the gobar gas plant to function, cattle dung is fed to the plant and gas is produced which is used as fuel while the slurry which is left over is a very good organic fertiliser and soil conditioner.” |