This study investigated the reduction of one antibiotic resistance gene (ARG, sul1) and one integron (intI1) within a multiple-antibiotic-resistant bacterium (ARB), Pseudomonas. HLS-6, during UV, chlorination and UV/chlorination. This bacterial strain can be thoroughly inactivated by UV/chlorination, but reactivation occurred after chlorination alone. For the removal of target genes (sul1 and intI1), the degradation rate order was as follows: UV/chlorination &gt; chlorination &gt; UV. The log reduction of sul1 and intI1 by UV/chlorination can achieved more than 3.50 and 4.00 log, respectively. Among the radicals produced in UV/chlorination, only the reactive chlorine species (Cl●, Cl2●- and ClO●) can degrade the target genes, while ●OH has no influence. With low chlorine dosage, sul1 was easier to be removed than intI1 by UV/chlorination. The log reduction of both sul1 and intI1 decreased with pH increasing during UV/chlorination. In the presence of sulfamethoxazole, UV/chlorination showed more advantages than direct UV and chlorination in the simultaneous removal of antibiotics, ARBs and ARGs. As for the formation of disinfection by-products (DBPs) during the HLS-6 ARB disinfection, UV/chlorination enhanced the yields of trihalomethanes (THMs), haloketones (HKs) and haloacetonitriles (HANs) compared with chlorination alone. But in the coexistence of Br- and I-, the UV/chlorination of ARB could reduce the formation of THMs, HKs and highly toxic I-THMs compared with chlorination, especially in the condition of high Br-/I- molar ratio. Therefore, UV/chlorination should be an effective method for risk control of ARBs, ARGs and DBPs in drinking water disinfection.

Risk control of antibiotic-resistant bacteria, antibiotic-resistance genes and disinfection by-products during UV/chlorination process

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.