Anaerobic ammonium oxidation coupled to Fe(III) reduction: Discovery, mechanism and application prospects in wastewater treatment

Fe(III) reduction coupled with anaerobic ammonium oxidation is known as Feammox. Feammox, which was first discovered in wetland ecosystems, has the potential to be used in wastewater treatment systems due to its ability to remove ammonium. Feammox can produce N2, NO2- or NO3- through the reduction of Fe(III) and oxidation of ammonium, which is a potential process to nitrogen loss from aquatic ecosystems and terrestrial ecosystems. The Acidimicrobiaceae sp. A6 was the first Feammox functional bacteria that was successfully isolated from wetlands. The nitrogen removal effect of Feammox can be influenced by many environmental factors, such as pH, organic matter, and different sources of Fe(III). Feammox has broad application prospects, but more exploration is needed to apply this principle to wastewater treatment. This review introduces the development, mechanism, functional microbes and factors affecting the Feammox process, and discusses its potential applications.