question_answer

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

Answer:

Microbes like aerobic or 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 helps to reduce the BOD of water as they consume organic matter. Anaerobic bacteria are added in anaerobic sludge digesters, where they digest the sludge and form biogas.