Name the two different categories of microbes naturally occurring in sewage water. Explain their role in cleaning sewage water into usable water.

Explanation

Aerobic and anaerobic bacteria or fungi exist in sewage water. After the primary treatment of water, aerobic bacteria are added in -aeration tanks. Growth of these bacteria reduces BOD as they consume organic matter. Anaerobic bacteria are added in anaerobic sludge digesters, where these digest the sludge and form biogas, etc..