Flocs produced in the secondary treatment plant of the sewage comprises of,

Options

A. Algae and Fungi
B. Only Algae
C. Viruses
D. Bacteria and fungi

Answer

To answer the question regarding what flocs produced in the secondary treatment plant of sewage comprises of, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Sewage Treatment Process**:
- Sewage treatment is divided into three main phases: primary, secondary, and tertiary treatment.
- The primary treatment involves physical processes like skimming, filtering, and sedimentation.

**Hint**: Remember the three phases of sewage treatment and their characteristics.

2. **Identify the Role of Secondary Treatment**:
- The secondary treatment primarily involves biological processes where microorganisms play a crucial role in decomposing organic matter present in the sewage.

**Hint**: Focus on the biological aspect of the secondary treatment.

3. **Know the Composition of Flocs**:
- During secondary treatment, the primary effluent (which is the output from the primary treatment) is aerated in large tanks along with a group of microbes.
- These microbes include bacteria and fungi, which are essential for the decomposition of organic substances.

**Hint**: Think about the types of microorganisms involved in decomposition.

4. **Eliminate Incorrect Options**:
- Algae are photosynthetic organisms and do not contribute to the decomposition process in this context.
- Viruses are not involved in the decomposition of organic matter in sewage treatment.

**Hint**: Consider the roles of different organisms in the sewage treatment process to eliminate incorrect options.

5. **Conclude with the Correct Answer**:
- Based on the above points, the correct composition of flocs produced in the secondary treatment plant of sewage comprises mainly of bacteria and fungi.

### Final Answer:
The flocs produced in the secondary treatment plant of sewage comprise of **bacteria and fungi**.