The mixture of gases released during anaerobic digestion of sludge is called

Options

A. methane
B. carbon dioxide
C. biogas
D. flammable gases

Answer

**Step-by-Step Solution:**

1. **Understanding Anaerobic Digestion**: Anaerobic digestion is a biological process that breaks down organic matter in the absence of oxygen. This process is commonly used for the treatment of sludge, which is a byproduct of wastewater treatment.

2. **Identifying the Mixture of Gases**: During anaerobic digestion, various gases are produced as a result of the breakdown of organic materials. The primary gases released include methane (CH4) and carbon dioxide (CO2).

3. **Composition of Biogas**: The mixture of gases produced during this process is commonly referred to as biogas. Biogas primarily consists of:
- Methane (50-70%)
- Carbon Dioxide (30-40%)
- Trace amounts of other gases such as nitrogen, hydrogen, and hydrogen sulfide (H2S).

4. **Conclusion**: Therefore, the correct answer to the question regarding the mixture of gases released during anaerobic digestion of sludge is "biogas".

**Final Answer**: Biogas

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