氯化消毒副产物NDMA的生成与控制研究进展

Review on Formation and Control of Chlorination Disinfection By-product NDMA during Water Treatment

NDMA(N-Nitrosodimethylamine)是水处理领域新近发现的一种氯化消毒副产物,由于其具有检出率高、致癌风险大、难以有效去除等特性,已成为国际关注的重要水质问题之一。饮用水中的NDMA主要产生于氯化消毒过程,尤为严重的是氯胺消毒过程,而臭氧和过氧化氢氧化基本不产生NDMA。NDMA为亲水性小分子有机物,常规处理和深度处理均难于有效去除,而且管网中的浓度显著高于出厂水。目前控制饮用水中NDMA的常用方法是紫外线照射,但能耗较高。其他方法如延长自由氯接触时间和采用高铁酸盐预氧化、反渗透、臭氧/过氧化氢高级氧化工艺等也可以不同程度地控制NDMA及其前体物。

N-nitrosodimethylamine （NDMA） is a newly detected disinfection by-product occurring in the chlorinated drinking water. Since NDMA shows wide occurrence, high carcinogenicity risk and limited removal effect in water treatment, it has become one of crucial water quality issues of international concern. NDMA in drinking water is mainly produced during chlorination disinfection, especially chloramine disinfection, and it is not produced in the disinfection by AOP using ozone/hydrogen peroxide. Due to hydrophilieity and specific structure with low molecule weight, NDMA can not be effectively removed by both conventional water treatment processes and advanced treatment technology. Its concentration in distribution pipeline is significantly higher than that in the finished water. Currently, UV photolysis is an effective method to decompose NDMA in drinking water, with high energy consumption. Other methods, such as extending the contact time of free chlorine, pre-oxidation with ferrate, reverse osmosis, AOP using ozone/hydrogen peroxide, also can be used to control NDMA and its precursors to certain extent in water treatment.