O_3-BAC-Cl_2: A multi-barrier process controlling the regrowth of opportunistic waterborne pathogens in drinking water distribution systems  

作　　者：Lizhong Liu Xueci Xing Chun Hu Haibo Wang 

机构地区：[1]Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Key Laboratory for Water Quality and Conservation of the Pearl River Delta,Ministry of Education,Institute of Environmental Research at Greater Bay,Guangzhou University

出　　处：《Journal of Environmental Sciences》2019年第2期142-153,共12页环境科学学报（英文版）

基　　金：supported by the National Key Research and Development Plan (No.2016YFA0203200);the National Natural Science Foundation of China (No.51538013);the project of Chinese Academy of Sciences (No.QYZDY-SSW-DQC004)

摘　　要：Simulated drinking water distribution system(DWDS) treated with O_3-BAC-Cl_2(ozonebiological activated carbon-chlorine) was constructed to study its effects on the regrowth of five typical opportunistic pathogens(OPs). It was found that O_3-BAC-Cl_2 could significantly reduce the regrowth of target OPs in the effluents of DWDS compared with Cl_2 and O_3-Cl_2 with the same residual chlorine levels. However, the effect of O_3-BAC-Cl_2 on the average numbers of target OPs gene markers in the biofilms of DWDS was not apparent, suggesting that OPs in the biofilms of DWDS were tolerant to the upstream disinfection process. The quantification of target OPs in the BAC-filter column demonstrated that OPs decreased with the increase of depth, which was likely due to the organic nutrient gradient and microbial competition inside the BAC-filter. Increase in the ozone dose could further reduce the OPs at the bottom of the BAC-filter. Spearman correlation analysis demonstrated that some significant correlations existed between target microorganisms, suggesting potential microbial ecological relationships. Overall, our results demonstrated that the BAC-filter may act as a "battlefield"suppressing the OPs through microbial competition. O_3-BAC-Cl_2 could be an effective multibarrier process to suppress the proliferation of OPs in the bulk water of DWDS. However, OPs protected by the biofilms of DWDS should receive further attention because OPs may be detached and released from the biofilms.Simulated drinking water distribution system(DWDS) treated with O_3-BAC-Cl_2(ozonebiological activated carbon-chlorine) was constructed to study its effects on the regrowth of five typical opportunistic pathogens(OPs). It was found that O_3-BAC-Cl_2 could significantly reduce the regrowth of target OPs in the effluents of DWDS compared with Cl_2 and O_3-Cl_2 with the same residual chlorine levels. However, the effect of O_3-BAC-Cl_2 on the average numbers of target OPs gene markers in the biofilms of DWDS was not apparent, suggesting that OPs in the biofilms of DWDS were tolerant to the upstream disinfection process. The quantification of target OPs in the BAC-filter column demonstrated that OPs decreased with the increase of depth, which was likely due to the organic nutrient gradient and microbial competition inside the BAC-filter. Increase in the ozone dose could further reduce the OPs at the bottom of the BAC-filter. Spearman correlation analysis demonstrated that some significant correlations existed between target microorganisms, suggesting potential microbial ecological relationships. Overall, our results demonstrated that the BAC-filter may act as a "battlefield"suppressing the OPs through microbial competition. O_3-BAC-Cl_2 could be an effective multibarrier process to suppress the proliferation of OPs in the bulk water of DWDS. However, OPs protected by the biofilms of DWDS should receive further attention because OPs may be detached and released from the biofilms.

关 键 词：OPPORTUNISTIC PATHOGENS (OPs) O3-BAC-Cl2 DWDS qPCR 

分 类 号：X[环境科学与工程]