Which of the following is not one of the main pollutants found in industrial effluents?

Oxygen is not considered a pollutant in industrial effluent. Rather, it is a vital component of the wastewater treatment process as it supports the growth of aerobic microorganisms that are capable of breaking down pollutants in the wastewater. In contrast, low levels of dissolved oxygen can lead to anaerobic conditions that can result in the formation of harmful by-products and make it more difficult to treat the waste.

The main pollutants found in industrial effluent are typically toxic chemicals, heavy metals, organic matter, and pathogens. These pollutants can have harmful impacts on the environment and human health and need to be removed or treated before the wastewater can be safely discharged into the environment.