COD (Chemical Oxygen Demand) is a measure of the amount of oxygen required to oxidize organic and inorganic matter in water. It is an important parameter in the assessment of water quality and is widely used in wastewater treatment plants, industrial processes, and environmental monitoring. The oxidation of organic compounds is one of the main contributors to COD in water. Examples of organic compounds that can contribute to COD include:

1. Carbohydrates: These are organic compounds that provide energy to living organisms. They can be found in plant material, sewage, and food waste.

2. Proteins: These are large organic molecules made up of amino acids. They can be found in animal waste, dead plant material, and food waste.

3. Fats and oils: These are organic compounds that are commonly found in wastewater from food processing plants, restaurants, and other industrial processes.

4. Phenols: These are organic compounds that can be found in industrial wastewater, particularly in the chemical and petrochemical industries.

5. Alcohols: These are organic compounds that are commonly found in wastewater from breweries, distilleries, and other industrial processes.

The oxidation of these organic compounds results in the consumption of oxygen, which is reflected in the COD value. Higher COD values indicate a higher concentration of organic matter in water, which can lead to oxygen depletion and other environmental problems.

COD involves oxidation of organic as well as inorganic compounds while BOD involves oxidation of only organic compounds.