再生水地下回灌过程中溶解性有机物的组成结构变化及其特性

对再生水包气带渗滤过程进行模拟实验,分析此过程中总溶解性有机物(DOM)含量和结构组成的变化规律,并采用IHSS推荐方法提取主要有机物组成进行分析表征。结果表明:经回灌处理后,再生水ρ(COD)由57.90 mg/L(0 h)降低至21.50 mg/L(159 h),去除率达到63%;ρ(DOC)相应由12.40 mg/L降低至7.16 mg/L,去除率达到42%。荧光区域积分计算结果表明,再生水中DOM主要由芳香蛋白类物质和溶解性微生物代谢产物组成,包气带土壤介质中的DOM则主要由腐植酸类物质组成;受土壤DOM淋溶释放影响,实验过程中淋滤出水DOM组成主要以腐植酸类物质为主(占比>0.6)。SEM及EDS分析结果表明,腐植酸表面呈海绵状,主要由C(64.40%)、O(34.25%)元素组成,FTIR分析得出其中含有羟基和羧基等活性官能团,紫外可见光谱呈现单调而无特征性的现象,特征峰值计算显示所提取腐植酸属于大分子范畴。

COMPOSITIONAL STRUCTRE CHANGES AND CHARACTERISTICS OF DISSOLVED ORGANIC MATTERS DURING ARTIFICIAL GROUNDWATER RECHARGE WITH RECLAIMED WATER

This study carried out a laboratory column experiment to simulate the infiltration process, analyzed the variation of total dissolved organic matter (DOM) content and structural composition, and extracted the main organic components with the recommended method by IHSS for analysis and characterization. The results showed that after infiltration, the COD concentration in reclaimed water decreased from 57.90 mg/L (0 h) to 21.50 mg/L (159 h), and the removal efficiency reached 63%. Accordingly, the DOC concentration decreased from 12.40 mg/L to 7.16 mg/L, and the removal rate was 42%. Fluorescene regional integration results showed that aromatic protein-like substances and SMP-like substances were main components of DOM in reclaimed water; DOM in soil was mainly composed of humic acid (HA). Affected by the DOM leaching release in soil, the DOM of leachate from the experiment was mainly composed of HA (the proportion was more than 60%). The results of SEM and EDS analysis showed that the surface of HA was spongy, mainly composed of C (64.40%) and O (34.25%) elements. FTIR spectrum revealed that HA contained various functional groups such as hydroxyl and carboxyl groups. UV-Vis spectrum was monotonous and showed no characteristic. The ratios between characteristic peaks showed that the HA belonged to the macromolecular category.