Removal of Nitrogen Oxyanion (Nitrate) in Constructed Wetlands

The increasing levels of nitrogen oxyanion pollution especially nitrate in water environments have become a critical issues of concern because of the potential risk on ecology and human health. Owing to its distinctive merits of sustainability, lesser operational and maintenance expenditure, the utilization of constructed wetland systems for the treatment of wastewater has turned out to be predominant worldwide. Its nitrogen oxyanion removal performance has received significant attention in the last two decades. This chapter presents a comprehensive outline of the application of constructed wetlands (CW) for nitrogen oxyanion removal from water and wastewater. The removal mechanisms and transformations of nitrogen are also discussed. In addition, the major factors that influence the removal performances in CWs are elucidated, especially the types of carbon sources commonly used, and how it affects the denitrification process. This chapter would be useful to engineers and researchers in the field of water and wastewater engineering.