Wang Binquan, Xiong Xiaoting, Yang Risen, Jin Jiao, Eli Hendrik Sanjaya, Mohd Fadhil Md Din, AbdelGawad Saad, Elsayed A.E. Ali, Chen Hong
The nitrogen removal performance under progressively elevated ammonium concentrations (200–700 mg/L NH₄⁺-N) served as the primary focus of this 185-day study, using a Vertical Flow Screening Internal Circulation Bioreactor (VFSCBR) operated at an 8 h HRT. The sieve plate enabled effective sludge separation by particle size, which facilitated the establishment of distinct aerobic and anaerobic zones and supported high treatment efficiency. Through optimization of the aeration strategy, reactor performance was successfully restored, with total nitrogen removal efficiency (TNRE) reaching 86.00 ± 2.00 % (day 36) and remaining at 76.15 % (day 144) under high loading, demonstrating marked system resilience and operational stability. Microbial analysis revealed significant community shifts, with the relative abundance of Proteobacteria exceeding 30.00 %, along with clear enrichment of key functional taxa: Nitrosomonas increased from 0.77 % to 7.05 %, while anammox bacteria represented by Candidatus Brocadia and Candidatus Jettenia increased to 2.98 % and 4.76 %, respectively. These microbial–environmental correlations provided strong evidence for successful compartmentalization of sludge and dissolved oxygen, confirming the reactor's ability to maintain functional separation between the aerobic zone (dominated by AOB) and the anaerobic zone (enriched with AnAOB), thereby enhancing nitrogen removal efficiency. © 2026 Elsevier Ltd.
School of Hydraulic and Ocean Engineering, Changsha University of Science and Technology, Changsha, 410114, China; Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha, 410114, China; School of Transportation, Changsha University of Science and Technology, Changsha, 410114, China; Department of Chemistry, State University of Malang (Universitas Negeri Malang), Jl. Semarang No. 5, East Java, Malang, 65145, Indonesia; Department of Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, Johor, Skudai, 81310, Malaysia; Agricultural Engineering Research Institute (AEnRI), Agricultural Research Center (ARC), 12311, Egypt
