Comparison of nitrification performance in SBR and SBBR with response to NaCl salinity shock: Microbial structure and functional genes

• Published in: Environmental research 2024-07, Vol.252 (Pt 3), p.118917-118917, Article 118917
• Main Authors: Wen, Xuezhe, Cui, Liang, Lin, Huali, Zhu, Wenqiang, Shao, Zongze, Wang, Yong
• Format: Article
• Language: English
• Subjects: Bacterial community; Effect of NaCl salinity; Nitrification; Sequencing batch biofilm reactor
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2024.118917

Ammonia removal by nitrifiers at the extremely high salinity poses a great challenge for saline wastewater treatment. Sequencing batch reactor (SBR) was conducted with a stepwise increase of salinity from 10 to 40 g-NaCl·L−1, while sequencing batch biofilm reactor (SBBR) with one-step salinity enhancement, their nitrification performance, microbial structure and interaction were evaluated. Both SBR and SBBR can achieve high-efficiency nitrification (98% ammonia removal) at 40 g-NaCl·L−1. However, SBBR showed more stable nitrification performance than SBR at 40 g-NaCl·L−1 after a shorter adaptation period of 4–15 d compared to previous studies. High-throughput sequencing and metagenomic analysis demonstrated that the abundance and capability of conventional ammonia-oxidizing bacteria (Nitrosomonas) were suppressed in SBBR relative to SBR. Gelidibacter, Anaerolineales were the predominant genus in SBBR, which were not found in SBR. NorB and nosZ responsible for reducing NO to N2O and reducing N2O to N2 respectively had s strong synergistic effect in SBBR. This study will provide a valuable reference for the startup of nitrification process within a short period of time under the extremely high NaCl salinity. [Display omitted] •High efficiency nitrification was achieved in SBR and SBBR at the salinity of 40 g-NaCl L−1.•SBBR showed more stable nitrification performance than SBR after adapting to 4% NaCl salinity within 20 days.•No nitrite accumulation was found at the stable nitrification period under varying salinity.•More abundant microbial diversity prevailed in SBBR, especially anaerobic bacteria replacing nitrifiers as the dominant genus.•Synergistic interactions between norB and nosZ were induced by microaerobic zones in SBBR.