Hematite-facilitated microbial ammoxidation for enhanced nitrogen removal in constructed wetlands

Constructed wetlands (CWs) are widely applied for decentralized wastewater treatment. However, achieving efficient removal of ammonia ( NH_4^ + - N ) has proven challenging due to insufficient oxygen. In this study, natural hematite (Fe2O3) was employed as a CW substrate (H-CWs) for the first time to drive anaerobic ammonia oxidation coupled with iron(III) reduction (Feammox). Compared to gravel constructed wetlands (G-CWs), ammonia removal was enhanced by 38.14