黄河原水中消毒副产物前体物的组成特征及其化学预氧化处理效果对比

以取自河南省郑州市石佛原水厂的黄河原水为研究对象,系统研究了原水中消毒副产物(DBPs)前体物的组成规律,对比分析了3种预氧化剂(高锰酸钾、自由氯和二氧化氯)对原水中DBPs生成潜能的消减规律.试验结果表明:原水中DBPs的前体物均以小分子有机物和疏水性组分(52.51%)为主;分子量小于1 k Da有机物组分是生成含氮消毒副产物(N-DBPs)和三卤甲烷(THMs)的主要前体物;疏水性有机物是生成THMs的主要前体物,亲水性有机物是生成N-DBPs的主要前体物.经Cl2预氧化后,直接生成的DBPs随着自由氯投加量的增加而增加,Cl O2和KMn O4预氧化直接增加DBPs产生量.经3种预氧化剂氧化后,原水中三卤甲烷生成潜能(THMFP)均呈现一定的下降,其降低量依次为Cl O2Cl2KMn O4;然而3种预氧化剂都不能有效的减少含氮消毒副产物生成潜能(N-DBPFP),Cl O2预氧化和Cl2预氧化可增加N-DBPs生成潜能,尤其在较高投加量下,Cl2预氧化将大大增加N-DBPs生成潜能.为有效消减总DBPs生成潜能,水厂可优先采用KMn O4或Cl O2作为预氧化剂处理引黄水库或沉砂池水.

Composition of disinfection byproducts precursors in the Yellow River raw water and comparison of different pre-oxidation treatments

Raw water from Yellow River in Henan Province was collected for investigation of different disinfection by-products (DBPs) precursors. The comparisons were conducted for DBPs formation by three different pre-oxidation processes. It was found that the DBP precursors were mainly constituted of small organic molecules and hydrophobic organic matter (52.51%). The organic compounds with molecular weight<1 kDa were the main nitrogenous disinfection by-products (N-DBPs) precursors and trihalomethanes (THMs) precursors. Hydrophobic organic matter was the maximum THMs precursor while hydrophilic organic matter was the maximum N-DBPs precursor. For pre-oxidation of Cl₂, the formation of DBPs increased significantly as the Cl₂ concentration increasing. The trihalomethane formation potential declined during three pre-oxidation processes and the decrease followed the order of ClO₂> Cl₂> KMnO₄. However, no obvious phenomena were observed for all the three pre-oxidants on nitrogenous disinfection byproducts formation. Overall, ClO₂ is the best alternative pre-oxidant to control DBPs formation in Yellow River raw water.