Step 1: Understanding the Concept:
BOD (Biochemical Oxygen Demand) is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample.
Step 2: Key Formula or Approach:
The higher the BOD value, the more organic matter is present, indicating higher levels of pollution.
Step 3: Detailed Explanation:
Clean Water: BOD is typically less than 5 ppm.
Polluted Water: BOD values range from 10 to 15 ppm.
Highly Polluted Water: BOD values are 17 ppm or higher.
At values as high as 17 ppm, the dissolved oxygen is so depleted that fish and other aquatic life cannot survive.
Step 4: Final Answer:
The BOD of highly polluted water is 17 ppm.