The removal of floating and suspended solids from sewage through filtration and sedimentation is the part of

In a sewage treatment plant, what is used as an inoculum for the process in the aeration tank?

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 $(R)$?

Physical removal of large and small stable solid particles from the sewage through filtration and sedimentation is called

Which bacteria are used to treat sewage water?

Presence of $E. coli$ in water indicates