Sewage water is purified by ..........

What is the water obtained after the sedimentation process in sewage treatment called?

Choose the correct sequence for $\text{STP}$ (Sewage treatment plant).

Assertion $(A)$: There is a need for more sewage treatment plants in proportion to the human population.
Reason $(R)$: Biogas is produced as fuel energy in $STPs$.
Which option is correct for Assertion $(A)$ and Reason $(R)$?

Statement $S$: In the primary stage of sewage treatment,physical particle matter is removed from water through filtration and sedimentation.
Reason $R$: Through sedimentation,soil or small pebbles are removed.

Treatment of waste-water is done by the