Waste stabilization ponds are

1.Mainly oxidation ponds

2.Used to remove pathogens and organic contents

3.Natural treatment systems

4.Extremely quick

5.Most efficient in extremely cold weather

A1, 2 & 3 only ✓ Correct

B2, 3 & 4 only

C1, 2 & 5 only

D3, 4 & 5 only

Correct answer: (A) 1, 2 & 3 only

Explanation

Waste stabilization ponds are chiefly oxidation ponds, natural systems that remove pathogens and organic matter.

Statement 1 is right since they operate mainly as oxidation ponds.

Statement 2 is right as they cut pathogens and organic load using sunlight and microbes.

Statement 3 is right because they are low-technology natural treatment systems.

Statement 4 is wrong since they are slow, needing long retention, and Statement 5 is wrong as they work best in warm, sunny weather.

Their long detention time lets algae and bacteria break down waste with little energy input.

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