Anaerobic ammonium oxidation in a one-step,completely autotrophic nitrogen removal system

We explore the characteristics of anaerobic ammonium oxidation(ANAMMOX) using sludge drawn from a one-step,completely autotrophic nitrogen removal system.Batch experiments are adopted.The quality and quantity of the intermediates formed in the system are analyzed.The results show that the sludge possesses the ANAMMOX function.Some of the NH+4 and NO-2 are removed in the ANAMMOX metabolic pathway.That is to say,NO-2 first is reduced to NH2OH,and then NH2OH reacts with NH+4 to form N2H4,which subsequently is converted to N2.Other portions of the NH+4 and NO-2 are removed in a different ANAMMOX metabolic pathway in which the NH2OH and NO-2 are converted to N2O,then the N2O is converted to N2,and NH+4 is converted to NH2OH.The coupling between the NH+4 to NH2OH conversion process and the process of N2O being converted to N2 needs further research.