Investigation of Nitrogen Removal via CANON Process in a Single Stage Constructed Wetland System

M. Khajah, A.O. Babatunde



This research study attempts to explore the new route of nitrogen removal called the Complete Autotrophic Nitrogen removal Over Nitrite process (CANON) to enhance the nitrogen removal in constructed wetlands. To achieve high-rate nitrogen removal via CANON, a single stage tidal flow constructed wetland system was adopted by implementing internal downflow recirculation, shorter unsaturated time, and long saturated time. It was found that the recirculation strategy with shorter unsaturated time would limit the oxygen supply, which favoured partial nitrification and the anammox process. High inorganic carbon could promote both partial nitrification and anammox activities, providing a strong selective method to maintain the CANON route. By combining the control of oxygen supply (internal recirculation, six cycles a day) and high influent inorganic carbon concentration of 150 mg/L, this study achieved ammonium and total nitrogen removal of 98% and 67%, respectively, from synthetic domestic wastewater.