Advanced carrier materials for anammox in wastewater nitrogen removal

The management of nitrogen (N) pollutants in wastewater is a critical issue that must not be ignored, given that excessive nitrogen can have detrimental effects on both human health and the environment. Anaerobic ammonia oxidation (Anammox) is a highly efficient and energy-saving technology for N removal, attracting considerable attention in the field. Due to the properties of Anammox bacteria (AnAOB), such as a lengthy growth cycle, strict growth condition requirements, and vulnerability to loss with water flow, the application of Anammox is limited. The use of carrier-based biofilm immobilization is regarded as a feasible strategy for the preserving and protecting of AnAOB. This paper reviews the current research status of carriers for Anammox, focusing on typical carrier materials, comparison of different carrier materials, and improvement of carrier materials, aiming to promote the application of Anammox. The future development direction of this field is also anticipated. Carriers have attracted considerable attention due to their effectiveness for AnAOB fixation in Anammox processes. Herein, a comprehensive review of current research on carriers for Anammox in wastewater nitrogen removal is presented, focusing on typical carrier materials, comparison of different carrier materials, and improvement of carrier materials. The corresponding performances in these aspects are also discussed. Furthermore, the prospects for Anammox using carriers are presented.