Question

What is meant by BOD and COD?

Answer 1

BOD:

1. It refers to the Biochemical Oxygen Demand.
2. Biochemical Oxygen Demand is the amount of oxygen required by the microorganisms and bacteria for decomposing the dead remains of plants and animals or organic matter under aerobic conditions (under the presence of oxygen) at a specified temperature.
3. BOD is inversely related to the quality of water.
4. High BOD means less oxygen is available in the water, which is lesser for the oxygen-demanding species. Hence, it indicates low water quality and vice versa.

COD:

1. It refers to the Chemical Oxygen Demand.
2. Chemical Oxygen Demand is the amount of oxygen required to chemically oxidize organic matters by strong oxidants like Potassium dichromate.
3. In wastewater treatment plants, COD is used to measure the amount of oxygen required to break down the pollutants (organic matter).
4. High chemical oxygen demand in water indicates that higher amounts of pollutants are present in the water and decreased availability of Dissolved Oxygen (DO).