生物滞留系统间隙水DOM三维荧光光谱特征分析

Compositional Characteristics of Interstitial Water Dissolved Organic Matter in Bioretention Systems with Different Filling

为探明不同淹没区填料对生物滞留系统的净水效果的影响,采用三维荧光光谱研究间隙水溶解性有机物的组成成分和时间分布特征。三维荧光光谱显示,海绵铁环境间隙水中主要有机组分为微生物代谢产物(Ⅳ),火山岩与碎砖块中为类腐殖质(Ⅲ+Ⅴ);碎石块类腐殖质(Ⅴ)、简单芳香类蛋白(Ⅰ+Ⅱ)和微生物代谢产物(Ⅳ);48h后海绵铁和碎砖块相关联的水生环境中DOM的荧光峰削弱,而火山岩和碎石块相关联水生环境中DOM的荧光峰增强。出水的类腐殖质组分(Ⅲ+Ⅴ)荧光积分体积均有降低(平均58.04%),芳香类蛋白组分(Ⅰ+Ⅱ)均有上升(平均65.36%)。海绵铁去除溶解性有机物效果最好(84.52%),火山岩(77.25%)和碎砖块(77.90%)较好,碎石块(29.20%)最差。间隙水中有机物主要来源于微生物的代谢活动(HIX<4)。与类腐殖质相反,芳香类蛋白易被微生物利用,对微生物代谢活动和硝态氮反硝化有促进作用。生物滞留系统在设计时宜采用碎砖块和海绵铁填料,外加碳源宜选用易被微生物利用的有机物。

To find out the impact of different saturation filling in the treatment processof bioretention systems,composition and dynamics of dissolved organic matter in runoff were analyzed using three-dimensional excitation emission matrix fluorescence spectroscopy(EEM).The results indicated that the major organic compounds of interstitial water were microbial metabolites from sponge iron,fulvic-like substances from brick bat and volcanic,and aromatic protein-like substances,fulvic-like substances and biometabolism from chippings.After 48 h treatment,fluorescence peakof interstitial water associated with fulvic-like and brick bat were weakened,but volcanic and chippings were strengthened.The bestpurification of organic substance was obtained by sponge iron at 84.52%,followed by volcanic and brick bat at 77.25%and 77.90%respectively,and chippings at 29.20%.Thevolume fluorescence integral of fulvic-like substances in effluent of bioretention decreased to 58.04%on average,but aromatic protein-like substances increased on average to 65.36%.HIX of all samples were smaller than 4,which means the organic compounds mainly come from microorganism supersession activity.Aromatic protein-like substances degraded by microbes easily,which could promote microorganism activity and nitrogen removal by denitrification.The design suggests that sponge iron and brick bat would be better as the saturation filling.External carbon source would be able to choose organic compounds which are easily utilized by microbe.