What is biological nitrogen removal?

Biological nitrogen removal refers specifically to the process where nitrogen compounds, such as ammonia or nitrate, are biologically converted into nitrogen gas (N2) through microbial processes. This is an essential part of nitrogen cycling, particularly in treating wastewater, as it helps reduce nitrogen levels that can contribute to water pollution and eutrophication when released into the environment.

In this context, some key processes involved in biological nitrogen removal include nitrification, where ammonia is converted to nitrite and then to nitrate, followed by denitrification, where nitrate is further reduced to nitrogen gas. This transformation is significant because it effectively removes nitrogen from systems, returning it to the atmosphere and thus playing a crucial role in nutrient cycling and maintaining ecosystem balance.

The focus on nitrogen gas is critical because its removal helps regulate nitrogen levels in the environment, preventing the harmful effects associated with excess nitrogen, such as algal blooms in aquatic systems.