Abstract:Anaerobic ammonium oxidation (anammox) process is the most economical bioprocess for nitrogen removal from wastewater at present, which is conducive to the energy neutral of wastewater treatment plants. Anammox bacteria play a major role in this process. Anammox granular sludge, formed with anammox bacteria, is the most promising sludge form for anammox process, owing to the high settling rate, strong retention capacity, and strong resistance to environmental stresses. Focusing on anammox granules, this paper introduced the characteristics, species, and metabolic pathways of anammox bacteria, and the formation mechanism of anammox granular sludge, and reviewed the extracellular polymeric substance (EPS) and quorum sensing, which are closely related to the aggregation of anammox granular sludge. Moreover, we summarized the future research directions of anammox granules. This review is expected to serve as a reference for the subsequent research on anammox granules and the regulation of anammox process.
