Self-enriching anammox bacteria and in situ establishing anammox process in traditional wastewater treatment system

• Published in: Journal of water process engineering 2024-12, Vol.68, p.106503, Article 106503
• Main Authors: Ding, Xiang, Li, Yalin, Zhao, Jixiang, Miao, Yuanyuan, Zhao, Danchen, Li, Yitong, Gao, Zhongxiu, Shi, Junhui, Wang, Qin, Bi, Xuejun, Zhang, Jianhua
• Format: Article
• Language: English
• Subjects: Anammox bacteria; Microbial community structure; Municipal wastewater; Partial denitrification-anammox; Self-enrichment
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.106503

The difficulty of acquiring adequate anammox sludge inoculum often limited the practical application of mainstream anammox. The feasibility of self-enriching anammox bacteria (AnAOB) and in situ establishing anammox process in traditional nitrification and denitrification system treating municipal wastewater was investigated in this study. A continuous-flow reactor inoculated with ordinary nitrification biofilms and blank carriers was operated at ambient temperature. AnAOB was self-enriched in the reactor, and partial denitrification (PD)-anammox process was successfully established in situ. According to the microbial community structure analysis, Candidatus_Brocadia (the only identified AnAOB genus) increased from 0.02 % in seed sludge to 5.71 %, and some genera with the function of PD (Comamonadaceae and Denitratisoma) gradually became the dominant denitrifying bacteria in system, which could generate NO2−-N, promoting AnAOB growth and enrichment. Efficient nitrogen removal performance was obtained, and effluent total nitrogen (TN) concentration and nitrogen removal rate of the system were 8.2 ± 0.5 mg N/L and 0.4 ± 0.02 kg N/(m3∙d), respectively. Nitrogen transformation pathway analysis showed that anammox played a crucial part in nitrogen removal, which accounted for 75.3 ± 0.6 % of the TN removed. Overall, the study proposed a promising approach for promoting anammox process application via self-enriching AnAOB in traditional wastewater treatment system. The inoculum can be easily obtained and is conductive to full-scale application. [Display omitted] •AnAOB was self-enriched with the abundance of 5.71 % by seeding nitrification biofilm•Anammox process was established in situ in traditional wastewater treatment system•Anammox was the main nitrogen removal pathway and accounted for 75.3 % of TN removed•Synergy between PD and fermentation bacteria could promote AnAOB enrichment