自来水消毒对内毒素及微生物处理效果分析

目的 了解自来水厂中各处理环节内毒素与微生物指标的变化,为进一步优化水质提供依据。方法 于2013年8月份,分别采集湖北省武汉市Z水厂(汉江水源)和B水厂(长江水源)的水源水、混凝、沉淀、砂滤和出厂水5个环节的水样,内毒素检测采用《中华人民共和国药典》(2005版)中细菌内毒素鲎试剂法,菌落总数、总大肠菌群、大肠杆菌和耐热大肠杆菌检测按照GB/T5750.12-2006《生活饮用水标准检验方法-微生物指标》进行。结果 武汉市Z水厂进厂水内毒素含量为281.36 EU/mL,出厂水中内毒素含量为38.95 EU/mL;B水厂进厂水内毒素含量为216.32 EU/mL,出厂水中内毒素含量为29.37 EU/mL;Z、B水厂内毒素的总清除率分别为86.16%和86.42%;Z、B水厂源水中菌落总数分别为4.24×10⁴ CFU/mL和2.06×10⁴ CFU/mL,出厂水中均未检出;Z、B水厂源水中总大肠菌群含量均>2300 MPN/100 mL,大肠杆菌分别为266和1100 MPN/100 mL,粪大肠菌群分别为345和1700 MPN/100 mL,出厂水中均未检出总大肠菌群、大肠杆菌和耐热大肠菌群。结论 现有自来水处理工艺可以满足指示菌达标要求,但内毒素仍有一定残留。

Effect of disinfection treatment on endotoxin and microorganism in drinking water in Wuhan city

Objective To investigate changes in endotoxin and microbiological parameters after conventional drinking water treatment in main drinking water plants in Wuhan city and to provide a scientific basis for improvement of drinking water quality.Methods The water samples were collected in August 2013 from drinking water plant Z and B with source water from Yangze River and Hanjiang River.The level of endotoxin was determined with limulus amebocyte lysate test described in Chinese Pharmaeopoeia(2005 edition); standard plate-count bacteria,total coliforms,Escherichia coli,and thermotolerant coliform bacteria were detected according to GB/T5750.12-2006 "Standard Examination Methods for Drinking Water-Microbiological Parameters".Results The endotoxin content in raw water samples from drinking water plant Z and B were 281.36 endotoxin unit per ml(EU/ml) and 216.32 EU/ml and that in tap water samples were 38.95 EU/ml and 29.37EU/ml,with the endotoxin removal rates of 86.16% and 86.42% for the two plants,respectively.The value of standard plate-count bacteria for the raw water samples from drinking water plant Z and B were 4.24×10⁴ colony-forming unit(CFU)/ml and 2.06×10⁴ CFU/ml.The content of total coliforms in raw water samples from the two plants were all over 2 300 most probable number(MPN)/100 ml.The content of Escherichia coli and thermotolerant coliform bacteria were 266 MPN/100 ml and 345 MPN/100 ml for raw water samples from plant Z and 1 100 MPN/100 ml and 1 700 MPN/100 ml for the samples from plant B.The standard plate-count bacteria,total coliforms,Escherichia coli,and thermotolerant coliform bacteria were not detected for all tap water samples from the two plants.Conclusion The conventional drinking water treatment can meet the requirement of domestic standard for indicator bacteria,but endotoxin still exists in the output drinking water.