Abstract:

Recently, increasing attention has been paid to antibiotic resistant bacteria (ARB) in stormwater runoff. However, there were little data on ARB removal through electrocoagulation (EC) treatment. In this study, batch experiments were conducted to investigate key designs for ARB removal, role of SS, effects of water matrix, and potential risks after EC treatment under the pre-determined conditions. EC treatment with 5 mA/cm² of current density and 4 cm of inter-electrode distance was optimal with the highest ARB removal (3.04 log reduction for 30 min). The presence of SS significantly improved ARB removal during EC treatment, where ARB removal increased with the increase of SS levels when SS less than 300 mg/L. Large ARB removal was found under particles with size lower than 150 μm with low contribution (less than 10%) of the settlement without EC treatment, implying that the enhancement of ARB adsorption onto small particles could be one of the reasonable approaches for ARB removal through EC treatment. ARB removal increased firstly and then decreased with the increase of pH, while had proportional relationship with conductivity. After the optimal condition, there were weak conjugation transfer but high transformation frequency (5.5 × 10⁻² for bla_TEM) for target antibiotic resistance genes (ARGs), indicating that there could be still a risk of antibiotic resistance transformation after EC treatment. These suggested that the combination of EC and other technologies (like electrochemical disinfection) should be potential ways to control antibiotic resistance transmission through stormwater runoff.

 抽象的：

最近，雨水径流中的抗生素抗性细菌（ARB）受到越来越多的关注。然而，关于通过电凝 (EC) 治疗去除 ARB 的数据很少。在这项研究中，进行了批量实验来研究在预定条件下去除ARB的关键设计、SS的作用、水基质的影响以及EC处理后的潜在风险。采用5 mA/cm ²电流密度和4 cm电极间距离的EC处理是最佳的，具有最高的ARB去除率（30分钟减少3.04对数）。 SS的存在显着提高了EC处理过程中的ARB去除率，当SS低于300 mg/L时，ARB去除率随着SS水平的增加而增加。在尺寸小于 150 μm 的颗粒下发现大量 ARB 去除，且未经 EC 处理对沉降的贡献较低（小于 10%），这意味着增强 ARB 对小颗粒的吸附可能是通过以下方式去除 ARB 的合理方法之一：电导治疗。 ARB去除率随着pH的增加先增加后减少，与电导率成正比关系。最佳条件后，目标抗生素抗性基因（ARG）的接合转移较弱，但转化频率较高（ bla _TEM为 5.5 × 10 ^-2 ），表明 EC 处理后仍可能存在抗生素抗性转化的风险。这些表明，EC 和其他技术（如电化学消毒）的结合应该是控制抗生素耐药性通过雨水径流传播的潜在方法。