Question

What is primary treatment of sewage?

Answer 1

Primary treatment of sewage basically involves the physical removal of large and small particles, through filtration and sedimentation. This is done in many stages. Initially, floating debris is removed by sequential filtration and then the grit i.e. soil and small pebbles, is removed by sedimentation. All the solids that settle down, form the primary sludge and the supernatant forms the effluent. The effluent from the primary settling tank is further taken for secondary treatment.