Which of the following is used as a disinfectant in water treatement ?

Options

A. Alum
B. Charcoal
C. Kieselgurh
D. Potassium permanganate

Explanation

To determine which of the given options is used as a disinfectant in water treatment, we can analyze each option based on its properties and applications in water treatment processes.

### Step-by-Step Solution:

1. **Understand the Definition of a Disinfectant**:
- A disinfectant is a substance that kills bacteria and other microorganisms, thereby preventing infections. It is used to purify water by eliminating harmful pathogens.

2. **Evaluate Each Option**:
- **Alum**:
- Alum is primarily used as a flocculant in water treatment. It helps in the process of flocculation, where it causes impurities to clump together into larger particles (flocs) that can then be removed from the water. However, it does not kill bacteria or act as a disinfectant.
- **Charcoal**:
- Charcoal is used to absorb impurities from water. It acts as an adsorbent, trapping contaminants on its surface. While it improves water quality, it does not have disinfectant properties.
- **Quiesilver**:
- Quiesilver (often referred to as silver) is used in various applications, including toothpaste and some cleaning products. However, it is not commonly recognized as a disinfectant in water treatment processes.
- **Potassium Permanganate**:
- Potassium permanganate is known for its disinfectant properties. It is effective in killing bacteria and is often used in water treatment to disinfect and purify water. It can also be used in lower concentrations for wound disinfection.

3. **Conclusion**:
- After evaluating all the options, we find that the only substance that acts as a disinfectant in water treatment is **potassium permanganate**. Therefore, the correct answer is option number 4: **Potassium Permanganate**.