氯/氯胺和紫外顺序消毒对管网抗性基因的去除

为探究供水系统中氯/氯胺与低压紫外顺序消毒对抗生素抗性基因(ARGs)分布特征的影响,采用生物膜反应器模拟供水管网,对管网出水和生物膜进行60mJ/cm²低压紫外线(254nm)消毒,并利用高通量定量PCR技术检测模拟管网进、出水及生物膜内的典型ARGs和遗传原件(MGEs).结果表明,管网反应器运行150d,氯和氯胺管网出水ARGs总相对丰度分别为0.13和0.137,生物膜ARGs分别为2.45和0.277,表明供水管网中低剂量的氯或氯胺可有效降低水相和生物膜相中ARGs的相对丰度达90%,且氯胺消毒对生物膜中的ARGs控制作用更显著.氯和氯胺消毒后管网出水再经低压紫外线照射后,ARGs相对丰度分别为0.0682和0.0537,管网生物膜中ARGs的相对丰度分别为2.01和0.194.ARGs与MGEs间的相关性发生显著变化,转座子与strB和mepA的相关性增强,与ermX和tetM相关性减弱,而整合子与acrF、cmlA1-01、oprJ及tolC-01的相关性增强.研究表明,将紫外线消毒工艺设置在用水终端可以显著降低氯和氯胺管网水中ARGs丰度,但对管网生物膜中的ARGs影响较小.

Research on removal of antibiotic resistance genes in pipe networks by chlorine/chloramine and UV sequential disinfection

In order to explore the influence of chlorine/chloramine and low-pressure ultraviolet sequential disinfection on the distribution characteristics of antibiotic resistance genes (ARGs) in the water supply system, a biofilm reactor was used to simulate the water supply network. The effluent and biofilm of the pipe network were taken for 60mJ/cm² low-pressure ultraviolet (254nm) disinfection, and high-throughput quantitative PCR was used to detect the number of typical ARGs and mobile genetic elements (MGEs) in the inlet, outlet, and biofilm of the simulated pipe network. After 150days, the total relative abundance of ARGs in the effluent of chlorine and chloramine pipe network were 0.130 and 0.137, and the abundance of biofilm were 2.45 and 0.277, respectively. This indicated that low dose of chlorine or chloramine in the water supply pipe network could effectively reduce the relative abundance of ARGs in the water phase and biofilm phase by 90%, and chloramine disinfection has a more significant control effect on ARGs in biofilms. After UV disinfection, the relative abundances of ARGs in chlorine and chloramine disinfected pipe network water were 0.0682 and 0.0537, respectively. The relative abundances of ARGs in biofilms after chlorine and chloramine disinfection were 2.01 and 0.194, respectively. The correlation between ARGs and MGEs changed significantly. The correlation between the transposon and strB, mepA was enhanced, and the correlation with ermX and tetM was weakened, while the correlation between the integron and acrF, cmlA1-01, oprJ and tolC-01 was enhanced. The results showed that the ultraviolet disinfection can significantly reduce the abundance of ARGs in the chlorine and chloramine disinfected pipe network water, but it had less effect on the ARGs in the pipe network biofilms.