Question

What is the primary stage of waste treatment

Water is allowed to settle in large tank so that solid waste would settle in the bottom and Gases Float on the Top.

Microorganisms added into the waste water. Microorganisms use organic wastes as their food and eliminate these from water

Other harmful elements such as Inorganic Chemicals, harmful living organisms are removed so as to improve the quality of water

none of these

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Answer 1

none of these I think......

Answer 2

option a is correct

this process is also called decomposition.