Question

The purpose of providing ventilation in sewer is to avoid:-
1. Asphyxiation of sewer maintenance employees
2. Odourous gases
3. Explosive mixture of sewer gases
4. All of the above

Answer 1

Correct Answer - Option 4 : All of the above

Explanation:

Ventilation of sewer:

• Various gases are produced in sewers due to the purification of organic materials of sewage. These gases are very foul in nature, cause harm to human health and corrode the sewers.
• The gases so produced are highly explosive and may cause accidents. Due to the above difficulties, the sewers must be properly ventilated.

The following methods are adopted for ventilating the sewers: 

• Use of ventilating columns
• Use of ventilating manhole covers
• Proper design of sewers
• House vent and soil pipes
• Use of mechanical devices
• Artificial ventilation

Ventilation in sewer is needed to avoid:

• The danger of asphyxiation of sewer maintenance employee.
• The buildup of odourous gases such hydrogen sulphide, ammonia etc.
• The development of explosive mixture of sewer gases.
• Another reason for ventilating sewers is to ensure a continuous flow of sewage inside the sewer.