Limit of BOD prescribed by Central Pollution Control Board for the discharge of industrial and muncipal waste water into natural surface water:

Options

A. `lt` 100 ppm
B. `lt` 30 ppm
C. `lt` 3 ppm
D. `lt` 10 ppm

Answer

**Step-by-Step Solution:**

1. **Understand BOD**: BOD stands for Biological Oxygen Demand. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. A higher BOD indicates a higher level of organic pollution.

2. **Identify the Importance of BOD**: BOD is crucial for assessing water quality. It helps determine the pollution level in water bodies. A high BOD level suggests a significant presence of organic matter, indicating pollution.

3. **Review BOD Levels**:
- BOD of 1-2 ppm: Good water quality.
- BOD of 3-9 ppm: Slightly polluted water.
- BOD of more than 100 ppm: Highly polluted water.

4. **Central Pollution Control Board Guidelines**: The Central Pollution Control Board (CPCB) has set limits for BOD levels in discharged wastewater to control water pollution.

5. **Determine the Correct Limit**: According to the CPCB, the prescribed limit for BOD for the discharge of industrial and municipal wastewater into natural surface water is less than 10 parts per million (ppm).

6. **Final Answer**: The limit of BOD prescribed by the Central Pollution Control Board for the discharge of industrial and municipal wastewater into natural surface water is **less than 10 ppm**.

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