给水管网中耐氯菌的耐氯特性及机理研究

发布时间：2018-10-25 16:26

【摘要】：为了控制饮用水管网中的细菌再生长，国内外广泛使用含氯消毒剂对饮用水进行消毒处理。但一部分“耐氯菌”仍能在余氯浓度较高条件下存活。课题组之前在南方某城市饮用水管网中分离出3株“耐氯菌”，经鉴定分别为产粘液分枝杆菌、鞘氨醇单胞杆菌和藤泽式甲基杆菌。本论文以这3株耐氯菌作为研究对象，分别研究自由氯、一氯胺和二氧化氯对其悬浮菌体的消毒灭活特性，模拟研究耐氯性最强的分枝杆菌在管壁表面形成生物膜的过程，运用动力学模型分析其耐氯特性，根据菌体结构探索其耐氯机理。主要研究成果如下：（1）通过研究悬浮菌体的消毒灭活特性发现，对于三种含氯消毒剂，产粘液分枝杆菌的耐受性强于鞘氨醇单胞杆菌和藤泽式甲基杆菌；且三株细菌的耐氯性均强于大肠杆菌。对于分枝杆菌、鞘氨醇单胞杆菌和甲基杆菌，二氧化氯和自由氯的消毒效果好于一氯胺。因此，对于存在耐氯菌潜在威胁的饮用水，应采用强消毒剂（二氧化氯、自由氯消毒）；或者在使用氯胺消毒时，，定期停止加氨，用自由氯消毒来提高对耐氯菌的灭活效果。（2）相同浓度消毒剂对于附着状态分枝杆菌灭活效果远远差于悬浮分枝杆菌。因此，对于存在耐氯菌威胁的实际饮用水系统，推荐在短时间内投加高浓度强消毒剂实现对耐氯菌生物膜的有效控制。（3）运用动力学模型拟合分枝杆菌消毒特性，推荐采用Hom模型对于消毒剂灭活分枝杆菌进行定量化的描述。Hom模型完整综合的考虑了分枝杆菌的耐氯特性，以及菌群亚种差异和聚集团导致的拖尾现象。C的经验常数n＞1，说明分枝杆菌对于消毒剂具有耐受性。T的经验常数m＜1，符合拖尾的现象。（4）研究发现分枝杆菌的特殊细胞结构是其耐氯性的重要原因。分枝杆菌具有较好的疏水性，亲水性消毒剂不易进入细菌内部。分枝杆菌的细胞壁饱和脂肪酸含量高，使得消毒剂对其细胞壁攻击的难度较大，对其内部结构形成了较好的保护作用。在相同消毒剂情况下，分枝杆菌细胞膜受破坏程度最小。本文通过对于耐氯菌悬浮状态消毒灭活特性、附着状态消毒灭活特性、动力学模型和菌体结构进行耐氯特性研究，确定了控制耐氯菌的理论依据和方法。对于控制耐氯菌，保障饮用水安全具有重要意义。
[Abstract]:In order to control the bacterial growth in drinking water network, chlorine disinfectant is widely used to sterilize drinking water at home and abroad. However, some chlorogenic bacteria could survive under higher residual chlorine concentration. Three strains of chlorogenic bacteria were isolated from the drinking water network of a city in the south of China and identified as Mycobacterium sphingomonas and methylbacillus Fujisawa. In this paper, the disinfection and inactivation characteristics of free chlorine, monochloramine and chlorine dioxide suspension bacteria were studied respectively, and the process of forming biofilm on the surface of tube wall of the most resistant mycobacteria was simulated. The chlorine tolerance was analyzed by kinetic model and the mechanism of chlorine tolerance was explored according to the bacterial structure. The main results are as follows: (1) by studying the disinfection and inactivation characteristics of suspension bacteria, it was found that the tolerance of myxobacterium to three chlorinated disinfectants was stronger than that of sphingomonas and methylbacillus Fujisawa; The chlorine tolerance of three strains of bacteria was stronger than that of Escherichia coli. For mycobacteria, sphingomonas and methyl bacilli, chlorine dioxide and free chlorine were more effective than monochloramine. Therefore, strong disinfectants (chlorine dioxide, free chlorine disinfection) should be used in drinking water where there is a potential threat to chlorogenic bacteria; or ammonia addition should be stopped regularly when chloramines are used in disinfection, Free chlorine disinfection was used to improve the inactivation effect of chlorine-resistant bacteria. (2) the inactivation effect of the same concentration disinfectant on the attached mycobacterium was much worse than that on the suspension mycobacterium. Therefore, it is recommended that the effective control of chlorine-resistant biofilm can be achieved by adding high concentration of strong disinfectant in short time for the actual drinking water system which is threatened by chlorine bacteria. (3) to fit the disinfection characteristics of Mycobacterium by using kinetic model. Hom model is recommended for the quantitative description of inactivated mycobacterium disinfectant. The Hom model takes into account the chlorine tolerance of Mycobacterium. The empirical constant of C is n > 1, which indicates that Mycobacterium has tolerance to disinfectant. The empirical constant m of T is less than 1, which is consistent with the phenomenon of trailing. (4) The special cell structure of Mycobacterium is an important reason for its chlorine tolerance. Mycobacterium has good hydrophobicity, hydrophilic disinfectant is not easy to enter the bacteria. The high content of saturated fatty acids in the cell wall of Mycobacterium makes it difficult for disinfectants to attack the cell wall and has a better protective effect on its internal structure. In the case of the same disinfectant, the degree of damage to the cell membrane of Mycobacterium was the least. In this paper, the characteristics of chlorine tolerance of chlorine-resistant bacteria were studied in suspension state disinfection and inactivation characteristics, attached state disinfection and inactivation characteristics, kinetic model and bacterial structure, and the theoretical basis and method of controlling chlorine-resistant bacteria were determined. It is of great significance to control chlorogenic bacteria and ensure the safety of drinking water.
【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】：TU991.2

【参考文献】