摘要

       在本研究中，好氧颗粒污泥 (AGS) 在高浓度铵盐条件下运行，以去除三种氟喹诺酮类 (FQ)，即 3、300 和 900 µg 的环丙沙星 (CFX)、氧氟沙星 (OFX) 和诺氟沙星 (NFX) /L，分别。两个关键目标是研究污泥部分中抗生素抗性基因 (ARG) 和移动遗传元件 (MGE) 的差异分布，并评估 ARG 和 MGE 与硝化和反硝化细菌之间的相关性。 AGS 在 FQs 暴露下表现出优异的稳定性，亚硝酸盐氧化细菌 (NOB) 对 FQs 比铵氧化细菌 (AOB) 更敏感。比氧利用率 (SOUR) 显示 NOB 降低了 26.9%，但 AOB 的活性降低了 3 μg/L FQ 的 4.0%。 AGS 对 CFX 和 NFX 的去除效率比 OFX 好，并且效率随着浓度的升高而增加，除了 900 μg/L 的 FQ。升高的 FQ 浓度导致 intI1 和 Thauera 属的显着富集，而 qnrD 和 qnrS 没有积累。与硝化菌相比，FQs相关的ARGs和intI1基因优先存在于反硝化菌中，且反硝化菌的丰度随污泥大小呈下降趋势。在 AGS 系统中发现了两种降解喹啉的细菌，即 Alicycliphilus 和 Brevundimonas，可能分别携带 qnrS 和 qnrD。它们的相对丰度随着污泥尺寸的增加而增加，在小于 0.5 mm 的污泥中为 2.18%，在大于 2.0 mm 的污泥中增加到 3.70%，表明 AGS 可能是处理含 FQs 废水的不错选择。

       In this study, aerobic granular sludge (AGS) was operated under high levels of ammonium for removing three fluoroquinolones (FQs), i.e., ciprofloxacin (CFX), ofloxacin (OFX), and norfloxacin (NFX) at 3, 300, and 900 µg/L, respectively. Two key objectives were to investigate the differential distribution of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in sludge fractions and to evaluate correlations between ARGs and MGEs to nitrifying and denitrifying bacteria. AGS showed excellent stability under the exposure of FQs, with nitrite-oxidizing bacteria (NOB) more sensitive to FQs than ammonium-oxidizing bacteria (AOB). Specific oxygen utilization rates (SOUR) showed a reduction of 26.9% for NOB but only 4.0% of the reduced activity of AOB by 3 μg/L FQs. AGS performed better removal efficiencies for CFX and NFX than OFX, and the efficiencies increased with their elevated concentrations, except at 900 μg/L FQs. The elevated FQ concentrations led to a significant enrichment of intI1 and genus Thauera, while qnrD and qnrS showed no accumulation. Compared to nitrifiers, FQs relevant ARGs and the intI1 gene preferred to exist in denitrifiers, and the abundance of denitrifiers behaved a decreasing trend with the sludge size. Two quinoline-degrading bacteria were found in the AGS system, i.e., Alicycliphilus and Brevundimonas, possibly carrying qnrS and qnrD, respectively. Their relative abundance increased with the sludge size, which was 2.18% in sludge <0.5 mm and increased to 3.70% in sludge >2.0 mm, suggesting that the AGS may be a good choice in treating FQs-containing wastewater.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421004908