oxidation pond
oxidation ditch
aerated lagoons
trickling filters
aerobic only
anaerobic only
aerobic in lower compartment and anaerobic in upper compartment
anaerobic in lower compartment and aerobic in upper compartment
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
filtration