寒区湖库型水源供水系统中耐氯菌的生长

The growth of chlorine resistant bacteria in water supply sourced from lakes and reservoirs in cold region

摘要:

研究供水系统中耐氯菌的生长对饮用水中微生物安全的评估、预防和控制至关重要,为此,以寒区湖库型水源供水系统的主体水及生物膜为研究对象,对其中的异养菌和耐氯菌进行了检测,并利用扫描电子显微镜观察了生物膜的生物相.结果表明：自来水在管网输送过程中,余氯质量浓度大于0.2 mg/L的主体水中仍然存在细菌再生长现象.耐氯菌在所研究的供水系统中普遍存在,经水厂消毒和管网输送后主体水中的耐氯菌数量小于350 CFU/mL,而生物膜中耐氯菌数目一般高于主体水的耐氯菌数目2个数量级.未经消毒处理的滤后水和生物膜中耐氯菌数目均最多,而在清水池中生长的细菌大多比较耐氯.供水系统生物膜中的微生物能见杆菌和球菌,以杆菌居多.

Abstract:

The study on the growth of chlorine resistant bacteria in water supply systems is critical for the assessment, control, and prevention of microbiological safety associated with drinking water. In this study, bulk water and biofioms in water supply system sourced from lakes and reservoirs in cold region were investigated by the detection of heterotrophic bacteria and chlorine resistant bacteria, and the biota in the biofilm were observed by scanning electron microscope. Results showed that the bacteria regrowth still existed in the bulk water even within more than 0.20 mg/L free chlorine in the distribution systems. Chlorine-resistant bacteria survived pervasively in the studied water supply system. The chlorine-resistant bacteria in post-chlorination and distributed water were less than 350 CFU/mL. The number of chlorine-resistant bacteria in the biofilm was two orders of magnitude higher than that of the bulk water in general. The chlorine resistant bacteria presented most in pre-chlorination of sand filter water and biofilm, while almost all viable bacteria in the clearwell were chlorine-resistant bacteria. Microbial morphologies in the biofilms of water supply systems were composed of cocci and rod, with the latter especially predominated in the biofilms.