摘要

       最近开发了基于硫酸根（自由基 dotSO4-）的调节方法，如零价铁（ZVI，即 Fe0）或亚铁（Fe2+）活化过硫酸盐（S2O82-），但目前尚不清楚它们如何影响污水污泥中的细胞内和细胞外抗生素抗性基因 (ARG)。在本研究中，发现使用 ZVI/S2O82- 或 Fe2+/S2O82- 系统的调节处理，在酸性初始污泥 pH 值下，去除了污水污泥中的细胞内 ARGs 和 intI1 以及细胞外 intI1，但导致积累条件污泥中 aadA-01、aadA-02、aadA1、aadA2-03 和 strB 的细胞外 ARG。在用 ZVI/S2O82- 或 Fe2+/S2O82- 处理污泥期间，ARGs 和 intI1 的细菌宿主被严重裂解，将细胞内 ARGs 和 intI1 释放到细胞外环境，从而去除了污泥中的细胞内 ARGs 和 intI1，而释放的 ARGs 和 intI1主要被产生的自由基 dotSO4− 降解，以减弱大多数细胞外 ARG 和 intI1。然而，自由基 dotSO4− 对 aadA-01、aadA-02、aadA1、aadA2-03 和 strB 的细胞外 ARG 的降解能力相对较低，导致它们在条件污泥中积累。因此，可以采用基于dotSO4-的自由基调理方法来减少污泥中的ARGs，但后续的污泥脱水滤液处理需要更多的关注。

       Sulfate radical (radical dotSO4−)-based conditioning methods, such as zero-valent iron (ZVI, i.e., Fe0) or ferrous iron (Fe2+) activated peroxydisulfate (S2O82-), have recently developed to improve sludge dewaterability, but it remains unclear how they impact the intracellular and extracellular antibiotic resistance genes (ARGs) in sewage sludge. In this study, it was found that conditioning treatments that used ZVI/S2O82- or Fe2+/S2O82- system, at an acidic initial sludge pH, removed the intracellular ARGs and intI1 and the extracellular intI1 from sewage sludge, but led to the accumulation of extracellular ARGs of aadA-01, aadA-02, aadA1, aadA2-03, and strB in conditioned sludge. During sludge conditioning with ZVI/S2O82- or Fe2+/S2O82-, bacterial hosts of ARGs and intI1 were seriously lysed to release the intracellular ARGs and intI1 to the extracellular environment, thus removing intracellular ARGs and intI1 in sludge, while the released ARGs and intI1 were primarily degraded by the produced radical dotSO4− to attenuate most extracellular ARGs and intI1. However, the relatively lower degradation ability of radical dotSO4− for extracellular ARGs of aadA-01, aadA-02, aadA1, aadA2-03, and strB led to their accumulation in conditioned sludge. Therefore, radical dotSO4−-based conditioning methods can be employed to reduce ARGs in sludge, but the subsequent treatment of sludge dewatering filtrate requires more attention.

https://www.sciencedirect.com/science/article/abs/pii/S0304389419319363