_______is the first step of sewage treatment.

Options

A. Precipitation
B. Chlorination
C. Sedimentation
D. Aeration

Answer

C

Explanation

Primary treatment in sewage treatment involves physical removal of particles (large and small) from the sewage through filtration and sedimentation. Initially floating debris is removed by sequential filtration. Then the grit (soil and small pebbles) are removed by sedimentation.