污水厂二级出水中THMs前体物卤代活性荧光光谱分析

通过分析城市污水处理厂二级出水中溶解性有机物(DOM)及其XAD树脂分级组分的荧光光谱,研究了DOM的结构特性以及DOM中的THMs前体物在加氯消毒过程中的反应特性与荧光强度之间的相关性.三维荧光光谱显示DOM分级组分中均存在富里酸类、腐殖酸类、芳香性蛋白质类及微生物沥出物类荧光特征峰, 且以芳香性蛋白质类和富里酸类荧光物质为主.荧光光谱区域积分法(FRI)定量分析结果表明,4类荧光物质在DOM各分级组分中的累计荧光强度(ΦT,n)分布与其在二级出水中的分布趋势较相似,总体上呈现疏水性有机酸(HPO–A) >过渡亲水性有机酸 (TPI-A)>过渡性亲水性中性物质(TPI-N)>疏水性有机中性物质(HPO-N)>亲水性物质(HPI).此外,ΦT,n与单位浓度DOC在紫外254nm处的吸光度值(SUVA)及三氯甲烷生成活性(STHMFP)有较好的相关性,但与DOC相关性较差.同步荧光光谱结果表明,在单位DOC条件下,总DOM中稠环类芳香性物质的含量高于DOM各分级组分,而DOM各分级组分中稠环类芳香性物质的含量少于腐殖酸类物质的含量.

Fluorescence characterization of the reactivity of THMs precursors in secondary effluent

Fluorescence spectra were applied to investigate the characteristics and structures of the dissolved organic matter (DOM) in secondary effluent from a wastewater treatment plant. Correlations between the fluorescence intensity and specific trihalomethane formation potential (STHMFP) of the DOM fractions were analyzed as well. Excitation-emission matrix (EEM) results revealed that all DOM isolates contained aromatic proteins, fulvic acids, soluble microbial products and humic acids (dominated by the aromatic proteins and fulvic acids). The fluorescence regional integration (FRI) results showed that four fluorescent dissolved organic matters had the similar distribution trend in the DOM fractions with the Φ_(T,n) of the DOM isolates: HPO-A>TPI-A>TPI-N>HPO-N>HPI. Besides, normalized fluorescence volume (Φ_(T,n)) showed linear relationships with SUVA and STHMFP. Synchronous spectra revealed that the total DOM contained more polycyclic aromatic structures than its isolates, and in each DOM isolates, polycyclic aromatic structures were less than humic acids.