Question

4 a) Name three systems for treating sewage
before it flows out into waterways.​

Answer 1

Answer:

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Sewage treatment is done in three stages: primary, secondary and tertiary treatment.

Answer 2

Answer:

Answer In Step by Step

Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment. Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface.

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