Shi Yi-Jing, Yang Lei, Liao Sheng-Fa, Zhang Li-Guo, Liao Zi-Cong, Lan Min-Yi, Sun Feng, Ying Guang-Guo
SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China.
J Hazard Mater. 2021 Jul 15;414:125527. doi: 10.1016/j.jhazmat.2021.125527. Epub 2021 Feb 24.
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.
在本研究中，好氧颗粒污泥（AGS）在高浓度铵条件下运行，以去除三种氟喹诺酮类药物（FQs），即环丙沙星（CFX）、氧氟沙星（OFX）和诺氟沙星（NFX），其浓度分别为3、300和900μg/L。两个关键目标是研究抗生素抗性基因（ARGs）和移动遗传元件（MGEs）在污泥组分中的差异分布，并评估ARGs与MGEs与硝化细菌和反硝化细菌之间的相关性。在FQs暴露下，AGS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。特定氧利用率（SOUR）显示，3μg/L FQs使NOB降低了26.9%，而AOB的活性仅降低了4.0%。AGS对CFX和NFX的去除效率优于OFX，且除900μg/L FQs外，去除效率随浓度升高而增加。FQ浓度升高导致intI1和陶厄氏菌属显著富集，而qnrD和qnrS没有积累。与硝化菌相比，与FQs相关的ARGs和intI1基因更倾向于存在于反硝化菌中，且反硝化菌的丰度随污泥粒径减小而呈下降趋势。在AGS系统中发现了两种喹啉降解菌，即嗜环菌属和短波单胞菌属，它们可能分别携带qnrS和qnrD。它们相对丰度随污泥粒径增大而增加，在<0.5mm的污泥中为2.18%，在>2.0mm的污泥中增至3.70%，这表明AGS可能是处理含FQs废水的良好选择。
