摘要

      城市污水处理厂（WWTP）处理后的废水中存在抗药性细菌（ARB）和抗药性基因（ARG），可能对环境和公众健康构成威胁。因此，有助于减少污水处理厂最终废水中这些污染物的负荷的经济有效的技术是必需的。本研究旨在评估混凝法降低二级处理城市污水（STWW）中ARB和ARG负荷的能力，以及该工艺对细菌群落结构和多样性的影响。比较了合成物质硫酸铝和生物废料单宁的混凝性能。在凝血处理（Alu，Tan）之前和之后以及在室温黑暗中储存3天之后（RSTWW，RAlu，RTan）立即分析样品，以评估可能的再活化事件。两种混凝剂均能降低浊度和颜色，并在治疗后立即将细菌负荷（16srrna基因拷贝数、总异养菌数（HET）和ARB（对阿莫西林（FC/AMX）或环丙沙星（FC/CIP）耐药的粪大肠菌群）降低至1-2 log。两种混凝剂都降低了intl1的负荷，但平均而言，硫酸铝能够将分析的ARGs（blaTEM和qnrS）的含量降低到低于单宁的水平。贮藏后再活化主要发生在RTan中。在这些样本中，可培养群体的负荷和qnrS基因的流行率增加，有时比最初废水中发现的值高。在细菌群落中，γ-变形菌相对丰度增加，但RTan和RAlu模式不同。弧菌属、非细菌属和水螺菌属是罗氏菌和气单胞菌属中最丰富的一个属。这些菌群变化与RTan的HET和RAlu的FC/CIP的可培养菌数变化一致。综上所述，硫酸铝处理城市污水的综合性能优于单宁。

      The presence of antibiotic resistant-bacteria (ARB) and antibiotic resistance genes (ARG) in treated effluents of urban wastewater treatment plants (WWTP) may represent a threat to the environment and public health. Therefore, cost-effective technologies contributing to minimize loads of these contaminants in the final effluents of WWTP are required. This study aimed at assessing the capacity of coagulation to reduce the ARB&ARG load in secondary treated urban wastewater (STWW), as well as the impact of the process on the structure and diversity of the bacterial community. Coagulation performance using aluminium sulphate, a synthetic substance, and tannins, a biowaste, was compared. Samples were analysed immediately before (STWW) and after the coagulation treatment (Alu, Tan), as well as after 3-days storage in the dark at room temperature (RSTWW, RAlu, RTan), to assess possible reactivation events. Both coagulants decreased the turbidity and colour and reduced the bacterial load (16S rRNA gene copy number, total heterotrophs (HET), and ARB (faecal coliforms resistant to amoxicillin (FC/AMX) or ciprofloxacin (FC/CIP) up to 1-2 log immediately after the treatment. Both coagulants reduced the load of intl1, but in average, aluminium sulphate was able to decrease the content of the analysed ARGs (bla_TEM and qnrS) to lower levels than tannin. Reactivation after storage was observed mainly in RTan. In these samples the load of the culturable populations and qnrS gene prevalence increased, sometimes to values higher than those found in the initial wastewater. Reactivation was also characterized by an increment in Gammaproteobacteria relative abundance in the bacterial community, although with distinct patterns for RTan and RAlu. Curvibacter, Undibacterium and Aquaspirillum were among the most abundant genera in RAlu and Aeromonas, Pseudomonas and Stenotrophomonas in RTan. These bacterial community shifts were in agreement with the variations in the culturable bacterial counts of HET for RTan and FC/CIP for RAlu. In summary, the overall performance of aluminium sulphate was better than that of tannins in the treatment of treated urban wastewater.

        https://www.sciencedirect.com/science/article/abs/pii/S0043135419308309?via%3Dihub