氯胺及其与二氧化氯联用对原水管道溶解性有机物降解的影响

摘要

Effects of chloramine (NH2Cl) and its combination with chlorine dioxide(NH2Cl/ClO2)on dissolved organic matter (DOM) were studied by annular reactor. The characteristic of DOM was evaluated by monitoring removal efficiencies of dissolved organic carbon (DOC) and UV254, overall DOM concentration, specific DOM absorbance ratio and excitation-emission matrices spectra (EEMs). The results showed that the oxidants significantly affected the removal of overall DOM, DOC and UV254. The DOM removal efficiency was lower after NH2Cl/ClO2 compared with that of NH2Cl, however, the recovery efficiencies speed of them were similar in the two cases. The degradation of DOM, DOC and UV254 recovered on 5th day, 4th day and 1st day after oxidation, respectively. Aromatic rings were substituted predominantly with polar groups after oxidation, and thus the oxidant increased the biodegradable DOM. Overall, DOM fluorescence intensity had a decrease potential after oxidant, particularly for tryptophan-like fluorescence and humic-like fluorescence. The aromatic rings were easier targeted by NH2Cl/ClO2, however, much more functional groups such as hydroxyl, carboxyl and carbonyl, and higher biodegradable DOM were observed after NH2Cl, resulting in higher biodegradation of DOM. The DOC and UV254 degradation after NH2Cl or NH2Cl/ClO2 could both recover to a higher level than that in control. Therefore, compared to single NH2Cl, NH2Cl/ClO2 was proposed to use in the raw water distribution system for decreasing oxidant by-products.%采用环状反应器模拟原水输水管道，考察氯胺（NH2Cl）及其与二氧化氯联用（NH2Cl/ClO2）对溶解性有机物（DOM）、溶解性有机碳（DOC）和UV254降解以及有机物荧光特性的影响。结果表明：NH2Cl或NH2Cl/ClO2对DOC、UV254和DOM的降解均产生较大的影响。相比NH2Cl，NH2Cl/ClO2的影响更大，但是有机物降解的恢复速度没有明显差异，DOC、UV254和DOM的降解分别在停止投加氧化剂的第5 d、4 d和1 d恢复。投加氧化剂后，芳香族有机物以向易生物降解的极性有机物的转化为主，溶解性有机物的可生物降解能力增加。NH2Cl 和NH2Cl/ClO2作用后，类蛋白质物质以及紫外区类腐殖质类物质明显减少。NH2Cl/ClO2更易破坏有机物中的芳香族化合物的结构，而NH2Cl氧化使得有机物分子结构中羰基、羟基、羧基和胺基等官能团增加，从而有机物可生物降解能力较强。NH2Cl和NH2Cl/ClO2作用后，有机物降解作用可恢复至比未加氧化剂更高的水平，基于卤代副产物生成的考虑，相比NH2Cl，NH2Cl/ClO2更适合用于原水输水管道的氧化。