微污染水源中溶解性有机氮组成规律及其水处理特性

Studies on dissolved organic nitrogen compositions and water-treatment behavior in micro-polluted water

以上海市黄浦江和青草沙长江原水为对象,研究了两大水源水中溶解性有机氮(DON)的含量变化、分子组成特征及其在常规净水工艺中的去除效果,并对DON与常规水处理指标间的相关性进行了分析.结果表明:两种原水以DOC、DON和UV254表征的有机物含量均以小分子量(<5kDa)和亲水性有机物为主;微污染黄浦江原水中同时存在外源性及内源性污染,而青草沙长江原水中内源性污染占主导地位;饮用水常规净水处理工艺对黄浦江原水中DON的去除率为40%,优于长江原水DON的去除率16.7%;黄浦江和长江原水DON浓度与DOC和UV254相关性良好,其相关系数分别为0.59,0.52和0.74,0.51;鉴于常规处理对DON去除效果有限,而DON是导致强三致特性含氮消毒副产物(N-DBPs)的总前体物,因此水厂应通过强化常规、深度处理等手段改善DON在净水工艺中的去除效果.

Dissolved organic nitrogen （DON） was the main precursors of toxic N-DBPs, and the removal effect of DON was unknown for conventional water treatment process （CWTP）. Variation of existence and molecular composition of DON in Huangpu River and the Yangtze River and the removal effect in CWTP was investigated. The results showed that the small molecular （〈 5kDa） and hydrophilic organic matters dominated the composition of DON, DOC and UV254 in both two kinds of raw water. In Huangpu River, both autochthonous and allochthonous NOM sources were found. However, the autochthonous sources dominated NOM sources in the Yangtze River. As the result of linear regression analysis of DON and regular water indexes, DON was moderately correlated to DOC with coefficient of 0.59 in Huangpu River and 0.52 in Yangtze River. DON was also correlated to UV254 with coefficient of 0.74 and 0.51 respectively. The DON removal rate by CWTP in the Huangpu River （40.0%） was higher than Yangtze River （16.7%）. The great limitation of DON removal by CWTP indicated that the technology of enhanced conventional and advanced water treatment must be applied by the drinking water plants.