____________is the first step of sewage treatment

Options

A. Precipitation
B. Chlorination
C. Sedimentation
D. Aeration

Answer

**Step-by-Step Solution:**

1. **Understanding Sewage**: The first step is to understand what sewage is. Sewage refers to the wastewater generated from domestic activities, which includes water from sinks, toilets, and showers.

2. **Purpose of Sewage Treatment**: The primary goal of sewage treatment is to purify this wastewater before it is released back into the environment or reused. This is essential for preventing pollution and protecting public health.

3. **Initial Treatment Process**: The first step in sewage treatment is a physical treatment process. This process aims to clarify the sewage water.

4. **Sedimentation Process**: Within the physical treatment, the first specific process is sedimentation. Sedimentation involves allowing solid particles in the sewage to settle at the bottom of a tank due to the force of gravity.

5. **Components of Sedimentation**: The sedimentation process can be broken down into three parts:
- **Coagulation**: This is the process where chemicals are added to the sewage to help clump together smaller particles into larger ones.
- **Flocculation**: This is the gentle mixing of the sewage to encourage the clumped particles (flocs) to form.
- **Settling**: Finally, the larger particles settle to the bottom, separating from the clearer water above.

6. **Conclusion**: Therefore, the first step of sewage treatment is sedimentation.

**Final Answer**: Sedimentation is the first step of sewage treatment.

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