During the treatment of sewage water, the chemical process is carried out in which step of water treatment?

Options

A. Tertiary
B. Secondary
C. Primary
D. Quaternary

Answer

To determine in which step of sewage water treatment the chemical process is carried out, we can break down the sewage treatment process into its main stages:

### Step 1: Understand the Stages of Sewage Treatment
1. **Primary Treatment**: This is the initial stage where solid organic matter is separated from wastewater. This process mainly involves physical methods such as screening and sedimentation.

2. **Secondary Treatment**: In this stage, the remaining organic matter is treated biologically. The wastewater is pumped into a secondary clarifier where any remaining organic sediments are allowed to settle out.

3. **Tertiary Treatment**: This is the advanced treatment stage where chemical processes are employed. Chlorination is a common method used in this stage to kill any remaining bacteria. This is where the chemical treatment occurs.

4. **Quaternary Treatment**: This stage involves testing and analysis of the treated water to ensure it meets safety and quality standards.

### Step 2: Identify the Chemical Process
- The chemical process in sewage treatment primarily occurs during the **tertiary treatment** stage, where chemicals like chlorine are added to disinfect the water.

### Conclusion
Based on the breakdown of the sewage treatment stages, the correct answer to the question is that the chemical process is carried out during the **tertiary treatment** of sewage water.

### Final Answer
The chemical process is carried out in the **tertiary treatment** step of sewage water treatment.

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