再生水系统中VBNC病原菌复活特性与风险的研究
发布时间：2018-07-15 22:12
【摘要】：目前我国正大力推广再生水的应用，保障再生水的水质安全是关键问题。病原菌在消毒压力下会进入活性但不可培养（VBNC）状态，无法用培养法检测出，但仍保留原有的毒力因子和致病性，可在消毒压力解除后复活繁殖而导致再生水回用的微生物健康风险。本研究针对VBNC病原菌复活风险，建立了逆转录活性和细胞膜完整性的检测方法体系，深入分析再生水系统中VBNC病原菌的存在去除特性和复活特性，探究VBNC病原菌复活的关键影响因子；应用焦磷酸测序技术，研究病原菌的群落结构变化；评估再生水市政杂用的微生物健康风险。在此基础上提出控制VBNC病原菌复活的方法。 本研究结果表明，进水中可培养大肠杆菌、粪肠球菌、沙门氏菌、分枝杆菌的浓度水平为3~5LogCFU/100mL。经过深度处理工艺，出水中处于VBNC状态的大肠杆菌、粪肠球菌、沙门氏菌浓度水平为1.5~3.8Log CE/100mL，占各自总活性菌含量的40~100%；分枝杆菌对消毒剂的抗性较强，出水中VBNC状态分枝杆菌浓度为1Log CE/100mL，占总活性菌的20%。膜处理工艺对可培养菌与活性菌的去除量相近约为1Log。消毒工艺对培养菌的去除量可达2~3Log，对活性菌的去除量1Log，对分枝杆菌作用不显著。 再生水贮存输送过程中，处于VBNC状态的病原菌大量复活，四种细菌的复活率达0.3~2.9Log。余氯与微生物浓度水平存在相关性。有机物和营养元素会促进微生物在管网中的复活，但其变化与微生物的复活不存在显著相关性。 采用454焦磷酸测序分析再生水生产、贮存和输送过程中群落结构的变化，结果表明经过消毒工艺、贮存和输送，微生物群落结构发生显著变化。管网末端，Proteobacteria是主要的门类，包含大量病原菌Burkholderiales。采用典范对应分析（CCA），考察理化因子对生物群落的影响，发现TN、TP、NO3-N和TOC是最重要的影响因素。 对再生水用作市政杂用的微生物健康风险进行评价，，得出年健康风险值与病原菌浓度水平的相关曲线。再生水出厂中，VBNC病原菌含有的潜在风险值比可培养病原菌高2个数量级。经贮存输送后，该风险值成为显性风险值，影响再生水回用的微生物健康风险。
[Abstract]:At present, our country is popularizing the application of reclaimed water. It is a key problem to ensure the safety of reclaimed water quality. The pathogen can enter into the active but unculturable (VBNC) state under disinfection pressure, which can not be detected by culture method, but it still retains the original virulence factor and pathogenicity. Microbial health risks that can be reactivated to reproduce after disinfection pressure is released, leading to reuse of reclaimed water. In this study, the reverse transcription activity and cell membrane integrity of VBNC pathogens were analyzed by reverse transcriptase assay, and the removal and reactivation characteristics of VBNC pathogens were analyzed. To explore the key factors influencing the revival of VBNC pathogens; to study the community structure changes of pathogens by pyrosequencing technology; and to evaluate the microbial health risk of municipal mixed use of reclaimed water. On this basis, the method of controlling the resurrection of VBNC pathogens was put forward. The results showed that the concentration of Escherichia coli, Enterococcus faecalis, Salmonella and Mycobacterium in the influent was 3 5 LogCFU / 100 mL. After advanced treatment, the concentration levels of Escherichia coli, Enterococcus faecalis and Salmonella in VBNC in the effluent were 1.5 ~ 3.8Log CE / 100 mL, accounting for 40,100 of the total active bacteria, and the resistance of Mycobacterium to disinfectants was stronger. The concentration of Mycobacterium in VBNC state was 1 Log CE / 100 mL, accounting for 20% of the total active bacteria. The removal of culturable bacteria and active bacteria by membrane treatment process was similar to that of 1Log. The removal amount of culture bacteria was 2 ~ 3Log. the removal amount of active bacteria was 1Log. the effect on Mycobacterium was not significant. During the storage and transportation of reclaimed water, the pathogenic bacteria in the state of VBNC were resurrected in large numbers, and the resurrection rate of the four bacteria reached 0.3n2.9Log. Residual chlorine was correlated with microbial concentration. Organic matter and nutrient elements can promote the resurrection of microorganisms in the pipe network, but there is no significant correlation between the changes and the resurrection of microorganisms. 454 pyrosequencing was used to analyze the changes of community structure during the production, storage and transportation of reclaimed water. The results showed that the microbial community structure changed significantly after disinfection, storage and transportation. Proteobacteria at the end of pipe network is the main category, including a large number of pathogenic bacteria Burkholderia. Canonical correspondence analysis (CCA) was used to investigate the effects of physicochemical factors on biota. It was found that TNT TPNO3-N and TOC were the most important factors. The microorganism health risk of reclaimed water used as municipal miscellaneous was evaluated and the correlation curve between annual health risk value and pathogen concentration level was obtained. The potential risk value of VBNC pathogens in reclaimed water was two orders of magnitude higher than that of culturable pathogens. After storage and transportation, the risk value becomes dominant risk value, which affects the microbial health risk of reclaimed water reuse.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R123;X824
本文编号：2125543
[Abstract]:At present, our country is popularizing the application of reclaimed water. It is a key problem to ensure the safety of reclaimed water quality. The pathogen can enter into the active but unculturable (VBNC) state under disinfection pressure, which can not be detected by culture method, but it still retains the original virulence factor and pathogenicity. Microbial health risks that can be reactivated to reproduce after disinfection pressure is released, leading to reuse of reclaimed water. In this study, the reverse transcription activity and cell membrane integrity of VBNC pathogens were analyzed by reverse transcriptase assay, and the removal and reactivation characteristics of VBNC pathogens were analyzed. To explore the key factors influencing the revival of VBNC pathogens; to study the community structure changes of pathogens by pyrosequencing technology; and to evaluate the microbial health risk of municipal mixed use of reclaimed water. On this basis, the method of controlling the resurrection of VBNC pathogens was put forward. The results showed that the concentration of Escherichia coli, Enterococcus faecalis, Salmonella and Mycobacterium in the influent was 3 5 LogCFU / 100 mL. After advanced treatment, the concentration levels of Escherichia coli, Enterococcus faecalis and Salmonella in VBNC in the effluent were 1.5 ~ 3.8Log CE / 100 mL, accounting for 40,100 of the total active bacteria, and the resistance of Mycobacterium to disinfectants was stronger. The concentration of Mycobacterium in VBNC state was 1 Log CE / 100 mL, accounting for 20% of the total active bacteria. The removal of culturable bacteria and active bacteria by membrane treatment process was similar to that of 1Log. The removal amount of culture bacteria was 2 ~ 3Log. the removal amount of active bacteria was 1Log. the effect on Mycobacterium was not significant. During the storage and transportation of reclaimed water, the pathogenic bacteria in the state of VBNC were resurrected in large numbers, and the resurrection rate of the four bacteria reached 0.3n2.9Log. Residual chlorine was correlated with microbial concentration. Organic matter and nutrient elements can promote the resurrection of microorganisms in the pipe network, but there is no significant correlation between the changes and the resurrection of microorganisms. 454 pyrosequencing was used to analyze the changes of community structure during the production, storage and transportation of reclaimed water. The results showed that the microbial community structure changed significantly after disinfection, storage and transportation. Proteobacteria at the end of pipe network is the main category, including a large number of pathogenic bacteria Burkholderia. Canonical correspondence analysis (CCA) was used to investigate the effects of physicochemical factors on biota. It was found that TNT TPNO3-N and TOC were the most important factors. The microorganism health risk of reclaimed water used as municipal miscellaneous was evaluated and the correlation curve between annual health risk value and pathogen concentration level was obtained. The potential risk value of VBNC pathogens in reclaimed water was two orders of magnitude higher than that of culturable pathogens. After storage and transportation, the risk value becomes dominant risk value, which affects the microbial health risk of reclaimed water reuse.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R123;X824
【参考文献】
相关期刊论文 前2条
1 胡秀华;何苗;刘丽;李丹;施汉昌;;水中轮状病毒实时定量PCR外标准品的构建[J];环境科学;2008年02期
2 王秀娟;朱琳;陈中智;李宇;;细菌“活的不可培养状态”的生态意义及研究进展[J];微生物学通报;2008年12期
本文编号：2125543
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