School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR China.
School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR China; Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China.
Chemosphere. 2024 Sep;364:143225. doi: 10.1016/j.chemosphere.2024.143225. Epub 2024 Aug 30.
This study elucidated the influence on a partial denitrification (PD) system under 0-1 mg/L sulfamethoxazole (SMX) stress in a sequencing batch reactor. The results showed that the nitrite accumulation rate (NAR) significantly (P ≤ 0.01) decreased from 68.68 ± 9.00% to 49.05 ± 11.68%, while the total nitrogen removal efficiency significantly (P ≤ 0.001) increased from 23.19 ± 4.42% to 31.36 ± 2.73% in presence of SMX. The results indicated that SMX exposure switched the PD process to complete denitrification through the deterioration of the nitrite accumulation and the promotion of further nitrite reduction. The SMX removal loading rate increased from 0.21 ± 0.04 to 5.03 ± 0.77 mg-SMX/(g-MLVSS·d) with the extended reactor operation under SMX stress. Low SMX concentration exposure increased extracellular polymeric substances (EPS) content from 107.69 ± 20.78 mg/g-MLVSS (0.05 mg-SMX/L) to 123.64 ± 9.66 mg/g-MLVSS (0.5 mg-SMX/L), while EPS secretion was inhibited under high SMX concentration exposure (i.e., 1 mg-SMX/L). Moreover, SMX exposure promoted the synthesis of aromatic protein-like compounds and changed the functional groups as revealed by EEM and FTIR analysis. Additionally, SMX exposure significantly shifted the microbial community structures at both phylum and genus levels. Particularly, the abundance of Thauera, i.e., functional bacteria related to PD, considerably decreased from 41.69% to 11.62% after SMX exposure, whereas the abundances of Denitratisoma and SM1A02 significantly rose under different SMX concentrations. These outcomes hinted that the addition of SMX resulted in the shifting of partial denitrification to complete denitrification.
本研究阐明了在序批式反应器中，磺胺甲恶唑（SMX）浓度为 0-1mg/L 时，对部分反硝化（PD）系统的影响。结果表明，亚硝酸盐积累率（NAR）从 68.68±9.00%显著下降（P≤0.01）至 49.05±11.68%，而总氮去除效率则从 23.19±4.42%显著提高（P≤0.001）至 31.36±2.73%。结果表明，SMX 的存在通过亚硝酸盐积累的恶化和进一步亚硝酸盐还原的促进，使 PD 过程转变为完全反硝化。SMX 去除负荷率从 0.21±0.04mg-SMX/（g-MLVSS·d）增加到 5.03±0.77mg-SMX/（g-MLVSS·d），这是由于在 SMX 胁迫下延长了反应器的运行时间。低浓度 SMX 暴露会使胞外聚合物（EPS）含量从 107.69±20.78mg/g-MLVSS（0.05mg-SMX/L）增加到 123.64±9.66mg/g-MLVSS（0.5mg-SMX/L），而高浓度 SMX 暴露则会抑制 EPS 的分泌。此外，SMX 暴露促进了芳香族蛋白样化合物的合成，并通过 EEM 和 FTIR 分析改变了功能基团。此外，SMX 暴露显著改变了门和属水平上的微生物群落结构。特别是，Thauera 的丰度，即与 PD 相关的功能细菌，从暴露前的 41.69%显著下降至 11.62%，而 Denitratisoma 和 SM1A02 的丰度在不同 SMX 浓度下显著上升。这些结果表明，SMX 的加入导致部分反硝化向完全反硝化的转变。
