Enhancing nitrogen removal of carbon-limited municipal wastewater in step-feed biofilm batch reactor through integration of anammox

• Published in: Bioresource technology Vol. 381; p. 129091
• Main Authors: Cui, Huihui, Zhang, Liang, Zhang, Qiong, Li, Xiyao, Peng, Yongzhen, Wang, Chuanxin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2023
• Subjects: Ammonium Compounds; Anaerobic Ammonia Oxidation; Anammox; Biofilms; Biological nitrogen removal; Bioreactors - microbiology; Carbon; Denitrification; Low C/N; Nitrogen - analysis; Oxidation-Reduction; Partial denitrification; Sewage - microbiology; Step-feed process; Wastewater; Partial denitrification; Biological nitrogen removal; Step-feed process; Anammox; Low C/N
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129091

[Display omitted] •Enhanced mainstream anammox was achieved by integrating anammox into step-feed SBBR.•Advanced nitrogen removal efficiency of 96% was achieved without external organics.•Steady anammox activity was maintained in the system despite decreasing temperature.•Anammox was the main nitrogen removal pathway that contributed 88% to TIN removal.•Step-feed An/O/A can be easily applied by retrofitting existing treatment system. The biological nitrogen removal of municipal wastewater was successfully improved by integrating anammox in a step-feed sequencing biofilm batch reactor. Despite fluctuating influent carbon to nitrogen ratio (1.9–5.1) and decreasing temperature (24.1–16.3 ℃), nitrogen removal efficiency of 95.9 ± 1.4 % and nitrogen removal rate of 0.23 ± 0.02 kg N/(m3·d) were successfully maintained without requirement of external carbon sources. The advanced removal performance was mainly attributed to the enhanced anammox. Anammox bacteria presented a high relative abundance (42.9% in biofilms, 1.5% in flocs) and anammox activity was as high as 5.42 ± 0.12 mg N/(g volatile suspended solids·h). Further analysis suggested that flexible control of influent organic and ammonium through step-feeding could provide multiple substrate supply for anammox reaction, potentially resulting in stable combination of anammox with hybrid-nitrite-shunt processes. Overall, this study provides a promising anammox-related application with simple-control step-feed strategy for enhanced and stable nitrogen removal from carbon-limited municipal wastewater.