Which of the following in sewage treatment removes suspended solids?
Option 1 : Primary treatment
Option 2 : Secondary treatment
Option 3 : Tertiary treatment
Option 4 : Sludge treatment
Which of the following in sewage treatment removes suspended solids?
Option 1 : Primary treatment
Option 2 : Secondary treatment
Option 3 : Tertiary treatment
Option 4 : Sludge treatment