`BOD` of wastwater is estimated by measuring the amount of

Options

A. total organic matter
B. biodegradable organic matter
C. oxygen evolution
D. oxygen consumption

Explanation

To estimate the BOD (Biochemical Oxygen Demand) of wastewater, we need to follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of BOD**:
- BOD stands for Biochemical Oxygen Demand. It refers to the amount of dissolved oxygen that microorganisms will consume while decomposing organic matter in a water sample over a specified period of time at a specific temperature.

2. **Identify the Key Components**:
- BOD measures the oxygen required by microorganisms to break down organic matter. Therefore, it is directly related to the amount of organic material present in the water.

3. **Determine the Measurement Method**:
- To estimate BOD, we need to measure the oxygen consumption by microorganisms in the water sample. This is done by assessing how much oxygen is used over a set period (usually 5 days) at a specific temperature (usually 20°C).

4. **Analyze the Options Given**:
- The options provided are:
- A) Total organic matter
- B) Biodegradable organic matter
- C) Oxygen evolution
- D) Oxygen consumption
- Among these, the correct method to estimate BOD is by measuring the oxygen consumption (option D).

5. **Conclusion**:
- Therefore, the BOD of wastewater is estimated by measuring the amount of oxygen consumed by microorganisms in the sample.

### Final Answer:
The BOD of wastewater is estimated by measuring the amount of **oxygen consumption**.

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