Which of the following is mainly produced by the activity of anaerobic bacteria on sewage ?
- Propane
- Mustard gas
- Marsh gas
- Laughing gas
Answer
(3) Marsh gas
Solution
In the anaerobic sludge digester, anaerobic bacteria (methanogens) digest the bacteria and fungi of the activated sludge.
⇒ A mixture of gases such as methane, hydrogen sulphide and carbon dioxide (biogas) is produced.
∵ Methane (CH4) is commonly called marsh gas,
∴ marsh gas is mainly produced.
Answer: (3)