In piped water supply system water is often treated with chlorine to

Options

A. remove hardness
B. kill germs
C. increase oxygen level
D. remove algae

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: In a piped water supply system, water undergoes various treatment processes to ensure it is safe for consumption. One of these processes is disinfection.

2. **Filtration Process**: Initially, the water is filtered to remove larger particles such as dirt, algae, and other impurities. This is done in the filtration units.

3. **Disinfection with Chlorine**: After filtration, the next crucial step is disinfection. Chlorine is commonly used for this purpose. The primary reason for adding chlorine to the water is to kill harmful bacteria and germs that may be present.

4. **Conclusion**: Therefore, the correct answer to the question is that water is treated with chlorine to kill germs.

5. **Review of Other Options**:
- To remove algae: This is done during the filtration process, not with chlorine.
- To increase oxygen levels: This can be achieved through aeration, not chlorine.
- To remove hardness: Chemicals like sodium carbonate are used for this purpose, not chlorine.

### Final Answer:
In a piped water supply system, water is often treated with chlorine to kill germs.

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