再生水中典型PAHs垂向迁移特征研究

目的]探究在模拟灌溉条件下，再生水中典型多环芳烃的迁移特征和影响因素。方法]通过土柱模拟试验，以再生水中多环芳烃萘、菲、芘为对象，北京市东南郊再生水灌区典型土壤为试验介质，对再生水连续灌溉时多环芳烃的迁移情况以及土柱出水中DOM的性质进行分析。结果]实际土壤介质对多环芳烃的吸附能力不能单纯用土壤有机碳含量很好地描述，组成复杂的介质对多环芳烃的吸附能力增强，萘的实际阻滞因子超过理论值约7倍；多环芳烃在非均质介质中的迁移存在界面效应，土壤有机碳含量差距越大，界面效应越明显；孔隙水流速以及孔隙尺寸增大，会造成固相上多环芳烃的解吸，发生二次迁移。微生物活动能促进多环芳烃的迁移。结论]该研究可为建立基于地下水质量安全的再生水灌溉模式的提出奠定基础。

Experimental Research on Vertical Migration Feature of Typical PAHs in Reclaimed Water

Objective] The research aimed to study the transport characteristics of several kinds of typical polycyclic aromatic hydrocarbons （PAHs） in reclaimed water and its＇ influencing factors under simulated irrigation conditions. Method] In order to research the migration and transformation rule of naphthalene, phenanthrene and pyrene when irrigated continuously with reclaimed water and to analyze the characteris- tics of dissolved organic matters in effluent, the soil column experiment were carried out with typical soil as test medium from reclaimed water irrigation site of southwest suburb in Beijing City. Result] The results showed that the adsorption capacity of real soil to PAHs could not be described very well by soil organic carbon content only, the adsorption capacity was enhanced in complex composition soil. The real retardation factor of naphthalene was about 7 times more than the theoretical calculation value. There was interfacial effect during the migration of PAHs in heterogeneous soil medium. Large gap between adjacent soils in carbon content could cause relatively obvious interfacial effect. Retained PAHs in fine particulate medium could be released in water again when pore velocity of water flow and pore size increased. Dissolved organic matters could be changed by microbial activity with a increase in hydrophilic components. Conclusion] This research could lay a foundation for the proposal of reclaimed water irrigation mode based on the quality safety of underground water.