垃圾污染场地胶体吸附态铵在含水介质中迁移-滞留的机理研究

According to the scientific problem of groundwater pollution by the colloid-adsorbed ammonium of landfill contaminated site, the dynamics process of transport, retention and release of colloid-adsorbed ammonium of landfill leachate through water-bearing media in different hydrochemistry and hydrodynamic conditions are investigated by means of various scale experiment of physical simulation, numerical simulation and field test from the view of environmental hydrogeology, hydro-geochemistry, colloid and interfacial chemistry. The internal relationship of transport, retention and release of colloid-adsorbed ammonium in water-bearing media with aqueous chemical, and physical-chemical properties of water-bearing media, and acharacter of colloid are explored. The quantitative relation between the retention capacity of colloid-adsorbed ammonium on solid particle surface and solid particle size, and pH, ionic strength of aqueous solutions, and concentration, particle size, zeta (ζ) potential and electrophoretic mobility of colloid are set up. Furthermore, the micro-mechanism and macro-effect of transport, retention and release of colloid-adsorbed ammonium on the aquifer hydraulic conductivity reduction in porous media are explored. The diversities of the migration of colloid-adsorbed ammonium and dissolved ammonium in water-bearing media are analyzed, and mass balance between colloid-adsorbed ammonium and dissolved ammonium are contrasted. The results of the research will provide a foundation for accurate describing processes, quantitative evaluation and prevention the pollution of ammonium from landfill leachate to groundwater, and for evaluation, control and in-situ restoration of landfill contaminated sites.

针对垃圾污染场地胶体吸附态铵污染地下水的科学问题，基于环境水文地质学、水文地球化学和胶体与界面化学理论，采用不同尺度的物理模拟试验、现场试验和数值模拟方法，深入研究不同水化学和水动力条件下垃圾渗滤液胶体吸附态铵在含水介质中迁移、滞留和释放的动力学过程；揭示水化学变化、含水介质物理-化学性质、胶体自身性质与胶体吸附态铵释放、迁移-滞留的内在有机联系；建立固体颗粒表面胶体吸附态铵滞留量与固体颗粒大小、水溶液离子强度、pH、胶体浓度、粒度和动电性质(ζ电位和电泳淌度)之间的定量关系。在此基础上，进一步从微观和宏观角度探索胶体吸附态铵迁移、滞留、释放对含水介质渗透性的影响和效应；分析胶体吸附态铵与溶解态铵迁移的差异和质量平衡关系。本项目的研究将为精确掌握垃圾渗滤液铵对地下水污染的过程、定量评价和防治以及垃圾污染场地风险评估、控制和原位修复提供科学依据。

大量的垃圾污染场地已成为地下水主要污染源之一。高浓度铵氮是垃圾渗滤液重要的水质特征，也是地下水中主要的氮污染物。胶体吸附态铵氮是垃圾淋滤液铵氮的主要存在方式，研究胶体吸附态铵氮在含水介质中的迁移-滞留机理是重新认识地下水中铵氮迁移转化的突破口，也是全面、精确地描述铵氮在地下环境中迁移转化过程的关键。本项目针对垃圾污染场地胶体吸附态铵污染地下水的科学问题，深入研究了不同水化学和水动力条件下垃圾渗滤液胶体吸附态铵迁移-滞留、释放的动力学过程及其对含水介质渗透性变异的影响和效应；系统分析了胶体吸附态铵与溶解态铵迁移的差异和质量平衡关系；探索了水化学变化、含水介质物理-化学性质、胶体自身性质与胶体吸附态铵释放、迁移-滞留的内在有机联系；建立了固体颗粒表面胶体吸附态铵滞留量与固体颗粒大小、水溶液离子强度、pH、胶体浓度、粒度和动电性质之间的定量关系。研究成果可为精确掌握垃圾污染场地铵氮在地下环境中迁移转化规律、对地下水污染的定量评价和防治以及污染场地风险评估、控制和原位治理提供科学依据。