Following are the gases are produced during sewage treatment,:

Options

A. methane , hydrogen sulphide and carbon dioxide
B. methane, oxygen na hydrogen sulphide
C. hydrogen , sulphide , methane and sulphur dioxide
D. hydrogen sulphide, nitrogen and methane

Explanation

### Step-by-Step Solution:

1. **Understanding Sewage Treatment**: Sewage treatment involves multiple stages, including physical, biological, and chemical processes. The biological treatment stage is crucial as it involves the breakdown of organic matter by microbes.

2. **Role of Microbes**: During the biological treatment, aerobic microbes (like bacteria and fungi) initially break down the organic matter. After this, the leftover sludge, which contains undigested organic matter, is treated by anaerobic microbes.

3. **Anaerobic Digestion**: In the anaerobic digestion phase, two types of bacteria are involved: non-methanogenic and methanogenic bacteria. The methanogenic bacteria are particularly important as they digest the remaining organic matter.

4. **Gases Produced**: The methanogenic bacteria produce a mixture of gases as they break down the organic matter. The primary gases produced during this process include:
- Methane (CH4)
- Hydrogen Sulfide (H2S)
- Carbon Dioxide (CO2)

5. **Identifying the Correct Option**: Based on the gases produced during sewage treatment, we can analyze the options provided:
- Option 1: Methane, Hydrogen Sulfide, and Carbon Dioxide (Correct)
- Option 2: Methane, Oxygen, and Hydrogen Sulfide (Incorrect because oxygen is not produced)
- Option 3: Hydrogen Sulfide, Methane, and Sulphur Dioxide (Incorrect because sulphur dioxide is not produced)
- Option 4: Nitrogen (Incorrect as nitrogen is not a product of this process)

6. **Conclusion**: The correct gases produced during sewage treatment are Methane, Hydrogen Sulfide, and Carbon Dioxide. Therefore, the correct answer is Option 1.