During biological nitrogen removal, what is the conversion product of influent ammonia and TKN that is released into the atmosphere?

During biological nitrogen removal, the processes involved typically include nitrification and denitrification. During nitrification, ammonia (NH3) is converted into nitrite (NO2-) and then into nitrate (NO3-). However, it is during the subsequent process of denitrification that nitrate is further reduced, ultimately leading to the formation of nitrogen gas (N2). This nitrogen gas is then released into the atmosphere, completing the nitrogen cycle.

The conversion of influent ammonia and total Kjeldahl nitrogen (TKN) into nitrogen gas is a crucial step in reducing nitrogen pollution in wastewater. By converting these compounds into a gaseous form, it minimizes the impact of nitrogenous compounds on aquatic environments where excess nitrogen can lead to issues such as eutrophication.

Nitrate, nitrite, and hydrogen gas are products of various stages of nitrogen cycling; however, they do not represent the final conversion product that is released into the atmosphere during the biological nitrogen removal process. The correct focus here is on nitrogen gas, as it signifies the successful removal of nitrogen from the wastewater treatment system and its return to the atmosphere.