The Biochemical Oxygen Demand (BOD) is an important parameter that measures the amount of oxygen required by bacteria to break down organic matter present in a given water sample. It is a key indicator of water quality. Here, we need to determine the expected BOD values for clean water (A) and polluted water (B).
Step-by-Step Explanation:
Understanding BOD Levels:
Clean Water: For water to be considered clean, it generally has a low BOD, indicating that there is minimal organic pollution and microbial activity. A typical BOD value for clean water is less than 5 ppm (parts per million).
Polluted Water: In contrast, polluted water has a higher BOD. This is due to a higher concentration of organic material, which requires more oxygen for microbial decomposition. Polluted water typically has a BOD over 17 ppm.
The given options suggest different ranges for BOD values. We need to select the option that accurately reflects the usual BOD values for clean and polluted water:
Analyzing the Options:
Option 1: \( A>15, B>47 \) - This suggests both clean and polluted water have high BOD values, which isn’t accurate for clean water.
Option 2: \( A<5, B>17 \) - This reflects the expected BOD values where clean water has a BOD less than 5 ppm, and polluted water has a BOD greater than 17 ppm.
Option 3: \( A>50, B<27 \) - Suggests extremely high BOD for clean water, which is incorrect.
Option 4: \( A>25, B<17 \) - Suggests high BOD for clean water, and low for polluted, which is not logical.
The most logical and accurate option based on BOD standards is Option 2: \( A<5, B>17 \).
Therefore, the correct answer is expected BOD values for clean water (A) and polluted water (B) are \( A<5, B>17 \).
