Question

What is the key difference between primary and secondary sewage treatment?

Answer 1

Primary sewage treatment:
1. It involves the physical processes filtration and sedimentation.

2. During this small and large floating debris is filtered out followed by the sedimentation process that allows soil and small pebbles settle at the bottom.

3. The supernatant water is effluent sent for the secondary sewage treatment process.

Secondary sewage treatment:

1. It involves the physical process-aeration of effluent and the biological treatment of effluent with microbes.

2. Sedimentation of bacterial floes is done to aerobic sludge digesters for digestion.

3. The effluent from secondary treatments is released into natural water bodies such as rivers, streams.