Question

Which gases are produced in anaerobic sludge digestors ?

A. methane, hydrogen sulphide and oxygen

B. hydrogen sulphide and carbon dioxide

C. methane and carbon dioxide only

D. methane, hydrogen sulphide and carbon dioxide

Answer 1

The correct option is D

Explanation of the correct answer:

1. Biogas plant or anaerobic sludge digestors use anaerobic bacteria in the process formation of certain gases.
2. The maximum amount of gas produced is methane, also known as the marsh gas.
3. Hydrogen sulphide and carbon dioxide are also produced in addition to methane.
4. This process occurs in absence of oxygen and there is no oxygen produced in the process.

Explanation of the incorrect answers:

Option A:

1. Process in anaerobic sludge digestors occurs in absence of oxygen and there is no oxygen produced in the process.
2. Therefore, this option is incorrect.

Option B:

1. The maximum amount of gas produced is methane, also known as the marsh gas.
2. But it is not provided in this option.

Option C:

1. Hydrogen sulphide and carbon dioxide are also produced in addition to methane.
2. Hydrogen sulphide is not given in the option.

Final answer: Methane, hydrogen sulphide and carbon dioxide gases are produced in anaerobic sludge digestors.