What is a common method for removing nitrogen from wastewater?

Nitrification and denitrification is a widely recognized and effective method for removing nitrogen from wastewater. This two-step biological process involves specific types of bacteria that facilitate the conversion of ammonia, which is a common form of nitrogen in wastewater, into nitrate through nitrification. In the subsequent step, denitrification occurs where nitrate is converted into nitrogen gas, which is then released into the atmosphere. This process is essential in wastewater treatment as it helps in mitigating the issues related to nitrogen pollution, such as eutrophication in receiving water bodies.

In contrast, the other methods listed do not primarily target nitrogen removal. Filtration and sedimentation are primarily physical processes used for solids removal and do not specifically address nitrogen compounds. Chlorination and dechlorination are chemical processes used for disinfection and removing chlorine residuals, rather than targeting nitrogen. Oxidation and reduction processes generally apply to a broader range of pollutants and are not specifically focused on nitrogen removal, making nitrification and denitrification the best choice for effectively tackling nitrogen in wastewater treatment.