BOD of waste water is estimated by measuring the amount of

Options

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

Explanation

To solve the question regarding how the BOD (Biochemical Oxygen Demand) of wastewater is estimated, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding BOD**:
- BOD stands for Biochemical Oxygen Demand. It is a measure of the amount of oxygen that bacteria will consume while decomposing organic matter in water.

2. **Definition of BOD**:
- BOD is defined as the amount of oxygen consumed by microorganisms during the oxidation of organic matter in a sample of water over a specified period, usually 5 days at 20°C.

3. **Process of Measurement**:
- To estimate BOD, we need to measure how much oxygen is consumed by bacteria in a water sample over a certain period. This involves incubating the sample under controlled conditions.

4. **Identifying the Key Factor**:
- The key factor in determining BOD is the amount of oxygen consumed by the bacteria during the breakdown of organic matter in the water sample.

5. **Choosing the Correct Option**:
- Given the options:
- 1) Total organic matter
- 2) Biodegradable organic matter
- 3) Oxygen evolution
- 4) Oxygen consumption
- The correct answer is **option 4: oxygen consumption**, as BOD specifically measures the amount of oxygen consumed by bacteria during the decomposition of organic matter.

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

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