Question

If water is polluted, its BOD (biochemical oxygen demand) value is:

• A. < 1 ppm
• B. < 2 ppm
• C. < 3 ppm
• D. > 6 ppm

Answer 1

The correct option is D > 6 ppm

In water with a BOD level of 6-9 ppm, the water is considered somewhat polluted because there is usually organic matter present and bacteria are decomposing this waste. At BOD levels of 17 ppm or greater, the water supply is considered very polluted with organic waste.

Hence, the correct option is $\left(D\right).$