[Carbon and Nitrogen Removal Characteristics of ABR Decarbonization-CANON Coupling Process]

If municipal wastewater can be treated by the completely autotrophic nitrogen removal over nitrite (CANON) process, it will greatly reduce the energy consumption of municipal wastewater treatment. The CANON reactor with a fiber carrier was started up by seeding nitrosation sludge and anaerobic ammonia oxidation (ANAMMOX) sludge in the continuously stirred tank reactor (CSTR). An ABR decarbonization system was added to the front of the CANON system to build the ABR decarbonization-CANON coupling process to examine carbon and nitrogen removal characteristics of the whole system. The high throughput sequencing technology of MiSeq was also employed to analyze the structure of the microbial community before and after the reactivation. The results showed that mixing nitrosation sludge and ANAMMOX sludge in the CSTR reactor under controlled parameters (DO of 0.5-2 mg·L^-1; HRT for 6 h; pH of 8) allowed the CANON system to successfully start within 55 d, with a TN removal rate of 81%-87% and ammonia nitrogen load of 0.195 kg·(m³·d)^-1. The effluent COD concentration of the ABR decarbonizing system did not adversely affect the subsequent CANON system, and the TN removal rate of the ABR decarbonization-CANON process was between 74% and 87%. Additionally, the average concentration of COD in the effluent was 40 mg·L^-1. At the same time, the Proteobacteria gate significantly improved after the CANON system began, and the proportion of Sphingobacteria decreased to 6.8%. Nitrifying bacteria and anaerobic ammonia oxidizing bacteria in the CANON system continuously eliminated the inferior bacterial groups to become the dominant group in the reactor. The integrated ABR decarbonization-CANON process had a positive effect on the denitrification and decarbonization of urban sewage.