Research progress on the mechanisms of iron-assisted anaerobic ammonia oxidation process

How to promote the proliferation and metabolism of anammox bacteria, improve the nitrogen removal efficiency of anammox process, and ensure the long-term stable operation of the process are the hotspots of anammox research. Iron-assisted anammox is the most widely studied measure with high economical and practical potential. This paper briefly describes the iron-assisted anammox technology and its nitrogen removal performance. The mechanisms of iron-assisted anammox process in promoting anammox cells growth and enhancing systems nitrogen removal performance are summarized from the aspects of optimizing the habitats of anammox bacteria, stimulating the secretion of extracellular polymer, accelerating the accumulation of denitrification functional bacteria, inducing the evolution of cell microstructure, regulating the expression of key enzymes and functional genes, promoting signal molecular synthesis, and enhancing abiotic nitrogen removal. Finally, the iron-assisted anammox technology is summarized and prospected, and the concept of waste iron scrap-anammox process is proposed. © 2022 Chinese Society for Environmental Sciences. All rights reserved.