Name two things that can be made from sludge extracted during treatment of sewage.

Answer

**Step-by-Step Solution:**

1. **Understanding Sludge**: Sludge is the solid waste that is produced during the sewage treatment process. It is formed in various stages of treatment, particularly in the sedimentation tank.

2. **Sewage Treatment Process**: In a sewage treatment plant, sewage undergoes several processes. After the initial treatment, the solid waste (sludge) is separated from the liquid waste.

3. **Digestion of Sludge**: The sludge is then transferred to a digester tank where anaerobic bacteria, including methanogens, break down the organic matter present in the sludge. This process is called anaerobic digestion.

4. **Products of Digestion**: During the digestion of sludge, two main products are formed:
- **Biogas**: This is a mixture of gases, primarily methane, which can be used as a fuel.
- **Digested Sludge (Manure)**: The remaining material after digestion is rich in nutrients and can be used as manure or organic fertilizer.

5. **Final Answer**: Therefore, the two things that can be made from sludge extracted during the treatment of sewage are:
- Biogas
- Manure