摘要

       通过污水处理厂 (WWTP) 排放的抗生素抗性基因 (ARG) 已引起公众对其对人类健康和生态安全风险的日益关注。膜生物反应器 (MBR) 已被公认为去除大规模污水处理厂中 ARG 的有效方法，但其相对于传统工艺的优势尚未明确量化。为了解决这个问题，我们研究了四个包含平行 MBR 和传统工艺（氧化沟或序批式反应器）的全规模污水处理厂，以比较八种类型的 ARG（blaTEM、ermB、tetW、tetO、sul1、sul2、addD 和qnrS) 和 int1。一般来说，MBR 比并行进程（0.4-4.2 日志删除）更好地减少了 ARG（1.1-7.3 日志删除）。值得注意的是，进水中的主要 ARG，如 ermB、sul1 和 int1（106.39–107.79copies/mL），通过 MBR（1.5–7.3 log 去除）比传统工艺（0.8–3.4 log 去除）更有效。同时，活性污泥中这些 ARG 的分布在上述过程之间没有显着差异（p>0.05）。分离系数 (Ksw) 被提议用来表示固体分离对 ARG 去除的贡献，随后的分析显示，主要 ARG（ermB、sul1 和 int1）的 Ksw 值与 MBR 对它们的对数去除之间惊人的强相关性（R=0.79–0.96 , p<0.05)，而这种相关性在传统工艺中要弱得多 (R=0.33–0.37)，表明固体分离是去除主要 ARGs 和 int1 的主要途径。根据MBR中工艺操作与ARG去除之间的典型相关分析，污泥停留时间（SRT）似乎是影响主要ARG和int1去除的主要因素。该比较研究有助于进一步了解和操作 MBR 工艺以减少流出物中的 ARG。

       Antibiotic resistance genes (ARGs) discharged through wastewater treatment plants (WWTPs) has aroused growing public concern for its risk to human health and ecological safety. Membrane bioreactor (MBR) has been recognized as an effective approach to remove ARGs in full-scale WWTPs, but its advantage over traditional processes was not clearly quantified. To address this, we investigated four full-scale WWTPs containing parallel MBR and traditional processes (oxidation ditch or sequencing batch reactor) to compare the reduction of eight types of ARGs (blaTEM, ermB, tetW, tetO, sul1, sul2, addD, and qnrS) and int1. In general, MBRs reduced the ARGs (1.1–7.3 log removal) better than parallel processes (0.4–4.2 log removal). Notably, the dominant ARGs in the influent, such as ermB, sul1 and int1 (106.39–107.79 copies/mL), were more effectively reduced by MBRs (1.5–7.3 log removal) than traditional processes (0.8–3.4 log removal). Meanwhile, the distribution of those ARGs in activated sludge was not significantly different between aforementioned processes (p > 0.05). The separation coefficient (Ksw) was proposed to represent the contribution of solid separation on ARG removal, subsequent analysis revealed surprisingly strong correlation between Ksw values of dominant ARGs (ermB, sul1 and int1) and their log removal by MBR (R = 0.79–0.96, p < 0.05), while such correlation was much weaker in traditional process (R = 0.33–0.37), indicating solid separation was the major pathway for removal of dominant ARGs and int1. According to the canonical correlation analysis between process operation and ARG removal in MBR, sludge retention time (SRT) seemed to be the major factor affecting removal of dominant ARGs and int1. This comparative study can be helpful for further understanding and operating MBR process to reduce the ARGs in effluent.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718342013