In the sewage treatment, bacterial flocs are allowed to sediment in a settling tank. This sediment is called as

Options

A. Primary sludge
B. Activated sludge
C. Effluent
D. Grit

Answer

To solve the question regarding what the sediment formed from bacterial flocs in a sewage treatment settling tank is called, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The question pertains to sewage treatment, specifically focusing on the sediment that forms when bacterial flocs settle in a settling tank.

2. **Identify the Options**: The options provided are:
- Primary sludge
- Activated sludge
- Effluent
- Grit

3. **Analyze Each Option**:
- **Effluent**: This refers to the treated or untreated wastewater that flows out of a treatment plant. It is not the sediment we are looking for.
- **Grit**: This consists of heavier solid materials like sand, gravel, and other non-biodegradable solids. Grit is not the sediment formed from bacterial flocs.
- **Primary Sludge**: This is generated from the initial stages of sewage treatment, specifically from chemical precipitation and sedimentation processes. It does not involve biological organisms, so it is not the correct answer.
- **Activated Sludge**: This is the correct term for the sediment formed from bacterial flocs. It is the biomass produced from the biological treatment of sewage, involving aeration and the activity of bacteria and protozoa.

4. **Conclusion**: The sediment formed from bacterial flocs in a settling tank during sewage treatment is called **Activated Sludge**.

### Final Answer:
The sediment is called **Activated Sludge**.

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