Tennessee Wastewater Operator Practice Exam

What must occur first in the nitrogen conversion process within wastewater treatment?

1. Convert nitrite to nitrate

2. Convert ammonia to nitrite

3. Convert nitrate to nitrogen gas

4. Convert nitrous oxide to nitrogen

The correct answer is: Convert ammonia to nitrite

In the nitrogen conversion process within wastewater treatment, the initial step involves converting ammonia to nitrite. This process is carried out by specific bacteria during nitrification, a critical phase in the biological treatment of wastewater. During this stage, ammonia (which can be toxic to aquatic life) is oxidized by ammonia-oxidizing bacteria (AOB) to form nitrite. This is essential because before any further transformations can occur, the ammonia must be addressed to mitigate its harmful effects. After the conversion of ammonia to nitrite, subsequent steps can occur, such as the conversion of nitrite to nitrate and then ultimately to nitrogen gas during denitrification. Understanding this sequence is crucial because it helps wastewater operators manage the treatment process effectively. By focusing on the initial conversion of ammonia to nitrite, operators can influence the efficiency of the nitrogen removal process in wastewater treatment plants.