During sewage treatment, biogases are produced which includes :

Options

A. hydrogensulphide, methane, sulphur dioxide
B. hydrqgensulphide, nitrogen, methane
C. methane, hydrogensulphide, Carbon dioxide
D. methane, oxygen, hydrogensulphide

Answer

**Step-by-Step Solution:**

1. **Understanding Biogas Production**: Biogas is primarily produced during the anaerobic digestion of organic matter. This process occurs in the absence of oxygen and is facilitated by specific microorganisms.

2. **Key Components of Biogas**: The main component of biogas is methane (CH4), which typically constitutes about 60-70% of the total gas produced. Other components include carbon dioxide (CO2), which makes up about 30-40%, and trace amounts of gases such as hydrogen sulfide (H2S), hydrogen (H2), and sometimes nitrogen (N2).

3. **Analyzing the Options**:
- **Option 1**: Methane, hydrogen sulfide, and carbon dioxide. This option includes the main components of biogas, making it a strong candidate.
- **Option 2**: Methane, oxygen, and hydrogen sulfide. This option is incorrect because the presence of oxygen indicates an aerobic process, which is not applicable to biogas production.
- **Option 3**: Hydrogen sulfide, methane, and sulfur dioxide. This option is incorrect because sulfur dioxide is not a significant component of biogas.
- **Option 4**: Hydrogen sulfide, nitrogen, and methane. While methane is present, nitrogen and hydrogen sulfide are in trace amounts, making this option less accurate.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 1**: Methane, hydrogen sulfide, and carbon dioxide.