aerobic bacteria only

algae only

dual action of aerobic bacteria and anaerobic bacteria

sedimentation

4-8 hours

24 hours

10 to 15 days

3 months

sludge digestion

sludge disposal

sedimentation

filtration

large area is required for construction

maintenance and operation cost are high

BOD removal is very low

none of the above

4.5 to 6.0

6.5 to 8.0

8.5 to 10.0

10.5 to 12.0