饮用水中氯消毒的应用及存在的主要问题

氯消毒在饮用水净化过程中被广泛采用,我国99.5%以上的水厂用氯消毒,在美国也有94.5%的自来水厂用氯消毒。氯消毒一般采用预加氯和后加氯两种方式。氯在消毒的同时会产生三卤甲烷、二氯乙酸等消毒副产物。这些消毒副产物有致癌、致畸、致突变性和遗传毒性,对人体的健康存在一定的危害性。在氯消毒过程中,余氯量越多产生的消毒副产物就越多,而余氯量过少对病毒的灭活性较差,同时在输水管中细菌就会大量繁殖,加快管道的腐蚀。不同浓度的余氯排入水体还会对鱼类和水生生物造成不同程度的毒性影响。

Application of Chlorine Disinfection in Drinking Water and Its Problems

Chlorine disinfection is widely used in drinking water purification process, which is applied by 95% and 94. 5 % of water plants in China and USA respectively. There are two ways for chlorine disinfection, prechlorination and postchlorination. During the process of chlorine disinfection some by-preducts such as trihalomethane and dichloroacetic acid are produced, which are harmful to human health resulting from their eareinogenicity, teratogenicity, mutagenicity and genotoxicity. The more the residual chlorine exists, the more the by-products produce. On the contrary, too little residual chlorine existence results in poor effect of disinfection and a lot of bacteria grow and reproduce in pipelines leading to corrosion. Toxicity of residual chlorine with different concentration affects fish and aquatic in different degree.