$A$ sewage treatment process in which a part of decomposer bacteria present in the wastes is recycled into the starting of the process is called:

In the sewage treatment process,the decomposer bacteria present in the waste are recycled at the beginning of the process. This is called.........

Sewage or municipal waste should not be directly passed into rivers,streams and other water bodies because
$I.$ it contains human excreta and other organic waste
$II.$ it contains a number of pathogenic microbes
Which of the statement given above is/are correct?

What is sewage? Through what is sewage water passed before being disposed of?

During which process are flocs formed?

Statement $P$: $A$ major portion of organic matter in water is consumed by chemical processes.
Statement $Q$: Microorganisms,including bacteria,consume organic matter present in water.