During conventional biological processes, nitrogen is primarily transformed into which compound?

During conventional biological processes, nitrogen is primarily transformed into ammonia and biological sludge. This occurs in biological treatment systems, such as activated sludge processes, where organic material and nitrogenous compounds are broken down by microorganisms. During this process, organic nitrogen is converted into ammonia through the action of bacteria in a process known as ammonification.

Ammonia can further be oxidized to nitrite and then to nitrate in a process called nitrification, but the initial transformation predominantly yields ammonia and biological sludge. Biological sludge contains the biomass generated from the growth of microorganisms used in the process, which can include a significant amount of nitrogen. Thus, the transformation of nitrogen primarily results in the formation of ammonia, which is a critical step in the nitrogen cycle relevant to wastewater treatment and environmental health.