Tennessee Wastewater Operator Practice Exam

What is the primary role of denitrifying bacteria in wastewater treatment?

1. Degraders of organic pollutants

2. Producers of phosphorous

3. Conversion of nitrates to nitrogen gas

4. Consumption of heavy metals

The correct answer is: Conversion of nitrates to nitrogen gas

Denitrifying bacteria play a crucial role in the nitrogen cycle, particularly in the context of wastewater treatment. Their primary function is to convert nitrates (NO3-) into nitrogen gas (N2) through a process known as denitrification. This conversion is significant because it helps reduce excess nitrogen in wastewater, which can lead to water pollution, including eutrophication in receiving water bodies. By transforming nitrates into nitrogen gas, denitrifying bacteria effectively remove nitrogen from the water, thereby contributing to the overall treatment process and helping to maintain environmental balance. This process not only aids in preventing the negative impacts of nitrogen accumulation but also assists in maintaining the efficiency of wastewater treatment systems. In contrast, the other choices are primarily unrelated to the specific role of denitrifying bacteria. For instance, while some bacteria indeed degrade organic pollutants, this is not the primary role of denitrifiers. Similarly, denitrifying bacteria do not produce phosphorus or consume heavy metals; those functions are typically associated with other types of microorganisms within the ecosystem of a wastewater treatment facility.