A sewage treatement process in which a part of decomposer bacteria present in the waste is recycled into the starting of the process is called as

Options

A. primary treatment
B. activated sludge treatment
C. tetriary treatment
D. none of these

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the name of a sewage treatment process where decomposer bacteria are recycled back into the process.

2. **Identifying Sewage Treatment Processes**: There are several sewage treatment processes, including primary treatment, secondary treatment, and tertiary treatment. The primary treatment involves sedimentation, while tertiary treatment involves chemical treatments.

3. **Focusing on Secondary Treatment**: The secondary treatment is where biological processes occur, specifically involving decomposer bacteria. This is where we can find the recycling of bacteria.

4. **Activated Sludge Process**: In the secondary treatment, the activated sludge process is a key method. In this process, sewage is aerated in large tanks, which contain aerobic microbes (decomposer bacteria). These bacteria decompose organic matter in the sewage.

5. **Recycling of Bacteria**: In the activated sludge process, a portion of the activated sludge (which contains the decomposer bacteria) is recycled back into the aeration tanks to enhance the decomposition of incoming sewage. This recycling is crucial for maintaining the efficiency of the treatment process.

6. **Conclusion**: Based on the above steps, the sewage treatment process in which a part of decomposer bacteria present in the waste is recycled into the starting of the process is called **Activated Sludge Treatment**.

### Final Answer:
**Activated Sludge Treatment**