摘要

       污水处理厂排放的抗生素耐药基因（ARGs）因其对人类健康和生态安全的危害日益引起人们的关注。膜生物反应器（MBR）已被公认为是一种去除污水处理厂中ARGs的有效方法，但其相对于传统工艺的优势尚未得到明确的量化。为了解决这一问题，我们调查了四个全尺寸污水处理厂，其中包括并行MBR和传统工艺（氧化沟或序批式反应器），以比较八种ARGs（blaTEM、ermB、tetW、tetO、sul1、sul2、addD和qnrS）和int1的还原情况。通常，MBRs比并行进程（0.4-4.2日志删除）更好地减少ARGs（1.1-7.3日志删除）。值得注意的是，与传统工艺（0.8-3.4原木去除）相比，MBRs（1.5-7.3原木去除）能更有效地降低进水中的主要arg，如ermB、sul1和int1（106.39-107.79 拷贝/mL）。同时，活性污泥中这些ARGs的分布在上述过程中无显著差异（p＞0.05）。提出了分离系数（Ksw）来表征固体分离对去除ARG的贡献，随后的分析显示，优势ARG（ermB、sul1和int1）的Ksw值与MBR去除其原木的相关性强得惊人（R = 0.79-0.96，p < 0.05），而传统的相关性弱得多过程（R = 0.33-0.37），表明固体分离是去除优势ARGs和int1的主要途径。通过对MBR工艺运行与ARG去除的典型相关分析，污泥停留时间（SRT）似乎是影响优势ARGs和int1去除的主要因素。通过对比研究，有助于进一步认识和操作MBR工艺，降低出水中的ARGs。

       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 (bla_TEM, 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 (10^6.39-10^7.79 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 (K_sw) was proposed to represent the contribution of solid separation on ARG removal, subsequent analysis revealed surprisingly strong correlation between K_sw 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/pii/S0048969718342013?via%3Dihub