Performance and microbial characteristics of completely autotrophic nitrogen removal over nitrite process in different types of reactors

There are various types of reactors for completely autotrophic nitrogen removal over nitrite (CANON) process, but the advantages and disadvantages of different types of reactors and their scope of application still need to be studied. In this paper, high-throughput sequencing technology was used to analyze the microbial characteristics of four CANON reactors with similar and stable influent water quality conditions, and the applicable scenarios of different types of CANON reactors was clarified. At the gene level, the proportions of aerobic ammonia oxidizing bacteria (AerAOB), anaerobic ammonia oxidation bacteria (AnAOB) and denitrifying bacteria in a flocculent sludge sequencing batch reactor (FSBR), a membrane bioreactor (MBR), a biological aerated filter (BAF) and a granular sludge sequencing batch reactor (GSBR) were 16.88 %, 3.49 %, 19.36 % and 29.67 %; 9.51 %, 4.72 %, 5 % and 27.75 %; 7.12 %, 11.5 %, 6.81 % and 13.6 %. The results showed that FSBR was low nitrogen removal load and low stability in practical application. MBR can treat different concentrations of ammonia nitrogen wastewater by controlling the influent load. BAF can treat ammonia nitrogen wastewater with moderate influent load. GSBR has high removal load and can treat high ammonia nitrogen wastewater.