Introduction
When it comes to the pollution potential of wastewater, the BOD or Biological Oxygen Demand is an important parameter to consider. BOD refers to the amount of dissolved oxygen required by microorganisms to decompose the organic matter present in the wastewater. In general, the higher the BOD of the wastewater, the more polluting it is. In this article, we will explore why this is the case.

Explanation
When wastewater is discharged into a water body, it introduces a large amount of organic matter into it. The organic matter in the wastewater serves as a food source for microorganisms, which start to decompose it. During this process of decomposition, the microorganisms consume dissolved oxygen from the water. The amount of oxygen required by the microorganisms to decompose the organic matter is known as the BOD.

Effects of High BOD
When the BOD of the wastewater is high, it indicates that the wastewater has a large amount of organic matter that needs to be decomposed. This can have several negative effects on the water body into which the wastewater is discharged. Some of these effects are:

- Reduced oxygen availability: As the microorganisms consume oxygen to decompose the organic matter, the amount of dissolved oxygen in the water decreases. This can lead to oxygen depletion, which can have a negative impact on aquatic life.

- Formation of harmful byproducts: During the decomposition of organic matter, microorganisms produce byproducts such as ammonia, hydrogen sulfide, and methane. These byproducts can be toxic to aquatic life and can also contribute to the formation of harmful algal blooms.

- Increased turbidity: When the organic matter in the wastewater is decomposed, it can lead to the formation of suspended solids in the water. This can increase the turbidity of the water and reduce light penetration, which can have a negative impact on aquatic plants.

Conclusion
In conclusion, the BOD of wastewater is an important parameter to consider when assessing its pollution potential. A high BOD indicates that the wastewater has a large amount of organic matter that needs to be decomposed, which can have several negative effects on the water body into which it is discharged. Therefore, it is important to monitor and manage the BOD of wastewater to minimize its impact on the environment.

high BOD means more organic matter prsnt in sewage ..which need high oxygen to get digested by aerobic microorgamisms