What is a biological nutrient removal (BNR) system designed to do?

A biological nutrient removal (BNR) system is specifically designed to reduce nitrogen and phosphorus levels in wastewater through biological processes. This method leverages microorganisms to break down and assimilate these nutrients during the treatment process.

In BNR systems, various conditions are created to promote the growth of specific bacteria that can effectively uptake nitrogen and phosphorus. For example, nitrogen is typically removed through processes like nitrification and denitrification, while phosphorus is taken up by biomass or released under anaerobic conditions and then taken up when conditions are aerobic.

This technology is crucial in preventing eutrophication, a process whereby excess nutrients, primarily nitrogen and phosphorus, enter water bodies, leading to algal blooms, reduced oxygen levels, and harm to aquatic life. As such, BNR is a vital component of modern wastewater treatment to ensure the treated effluent meets environmental standards and protects water quality.