Nitrogen removal performance, ammonia oxidation contribution rate and community structure variation of ammonia-oxidizing microorganisms based on pure biofilm system

Nitrification is the key and rate-limiting step in the biological nitrogen removal process of wastewater. In order to quantify the contribution of ammonia-oxidizing microorganisms (AOMs) in the nitrification process and promote cooperation among microorganisms, so as to achieve highly efficient nitrification, this study constructed a kind of pure biofilm system based on anoxic/ oxic (AO) process, and comparatively explored the nitrification performance of four different fillers and the growth and enrichment of related microorganisms. The system has been running for 165 days.