Social Science (087) — AI-generated practice question

Treatment of industrial effluents is carried out in three stages:

(a) Primary Treatment – This involves mechanical processes such as screening, grinding, flocculation and sedimentation. It removes large solid particles and suspended impurities from the effluent.

(b) Secondary Treatment – This involves biological processes where microorganisms break down dissolved organic matter, reducing biological pollutants in the water.

(c) Tertiary Treatment – This involves biological, chemical and physical processes combined. It purifies the water to a high standard, making it safe for recycling and reuse.

Source: Control of Environmental Degradation, Chapter 6

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• The three stages follow a fixed sequence: mechanical → biological → biological/chemical/physical.
• Examiners expect all three stages named correctly with the type of process and what is achieved. One mark per stage.
• Do not add extra information not in the passage — keep it grounded in the source.