摘要

废水处理厂（WWTP）已被确定为抗生素抗性基因（ARG）的潜在来源，但是三次废水处理工艺对ARG的影响尚未得到很好的表征。因此，这项研究的目的是确定整个第三阶段污水处理厂中ARG的命运。通过定量聚合酶链反应（qPCR）对来自大型污水处理厂的固体和原污水，活性污泥，活性污泥，二级污水和三级污水的溶解级分中的两个ARG（sul1和bla）进行了定量。使用中试规模的介质过滤器进一步研究了三次介质过滤和氯消毒。结果表明，在处理的每个连续阶段，两种基因的溶解级分均降低。与固体相关的ARGs在活性污泥阶段增加，并在随后的每个阶段减少。总体减少量约为4 log10，其中第三级介质过滤和消毒的减少量最大。除第三级废水外，大多数ARGs与固体相关。没有证据表明在治疗过程中ARG的阳性选择。与未过滤的氯化二级流出物相比，通过过滤可提高氯对ARG的去除率。这项研究表明，与单独的二级处理相比，带消毒的第三级污水处理厂可以提供更高的ARG去除率。

Wastewater treatment plants (WWTPs) have been identified as potential sources of antibiotic resistance genes (ARGs) but the effects of tertiary wastewater treatment processes on ARGs have not been well characterized. Therefore, the objective of this study was to determine the fate of ARGs throughout a tertiary-stage WWTP. Two ARGs, sul1 and bla, were quantified via quantitative polymerase chain reaction (qPCR) in solids and dissolved fractions of raw sewage, activated sludge, secondary effluent and tertiary effluent from a full-scale WWTP. Tertiary media filtration and chlorine disinfection were studied further with the use of a pilot-scale media filter. Results showed that both genes were reduced at each successive stage of treatment in the dissolved fraction. The solids-associated ARGs increased during activated sludge stage and were reduced in each subsequent stage. Overall reductions were approximately four log10 with the tertiary media filtration and disinfection providing the largest decrease. The majority of ARGs were solids-associated except for in the tertiary effluent. There was no evidence for positive selection of ARGs during treatment. The removal of ARGs by chlorine was improved by filtration compared to unfiltered, chlorinated secondary effluent. This study demonstrates that tertiary-stage WWTPs with disinfection can provide superior removal of ARGs compared to secondary treatment alone.

https://www.mdpi.com/2073-4441/10/1/37