What does the first step in nitrogen removal involve?

The first step in nitrogen removal primarily involves the oxidation of ammonia to nitrate. This process, known as nitrification, is crucial in wastewater treatment because ammonia, which can be toxic to aquatic life, needs to be converted into less harmful forms. During nitrification, ammonia is first oxidized to nitrite by specific bacteria. Then, the nitrite is further oxidized to nitrate, which is a more stable and less harmful compound.

This process sets the stage for the subsequent step in nitrogen removal where nitrates can be transformed into nitrogen gas through denitrification, thereby completing the nitrogen cycle and allowing for the safe release of treated water into the environment. Other options relate to different aspects of wastewater treatment but do not accurately describe the initial step in nitrogen removal.