低影响开发(LID)生态滤沟技术对旱区城市路面径流的净化机理研究

With the acceleration of urbanization in China, the demand for urban non-point source pollution(NSP) control and rainwater management is increasingly prominent. The road is a critical source area of urban NSP. This project takes Xi'an city as research background, which is a typical city in resources water shortage and fragile ecological environment in northwest arid region in China. Through systematic tests which are small-scale experiment, pilot test, and field test, applying examination methods including the Biolog method, and combining with statistical analysis and model simulation, the purification process and mechanism of LID ecological filter ditch technology on non-point source pollutant(nitrogen, phosphor,COD,heavy metal, fat class, poisonous organic compounds(PCBs, PAHs)) of urban road surface runoff will be studied. From the water quality and quantity, the influence on purification effect of such factors as the packing combination style, the filler thickness, the wide of ditch, the depth of submerged area, the dosing of carbon source, the characteristics of in flow water and pollutants, the interval time of rainfall, the temperature, the vegetation conditions will be studied. The coupling quantitative relationship between purification effect and main influencing factors, as well as the mathematical simulation model will be established. The application of the mathematical model in eco-filter-ditch design will be discussed, and an example will be researched. The project has important scientific significance and application value for urban NSP control, rainwater management and sustainable development. Meanwhile, It will effectively promote the cross-cutting, innovation, and development of such interdisciplinary theories as hydrology, hydraulics, ecology, soil science, and environmental science.

随着我国城市化进程的加快，城市面源污染控制和雨洪管理的需求日益突出。道路是城市面源污染的关键源区，本项目以西北旱区典型资源性缺水、生态环境脆弱型城市西安市为研究背景，通过小试、中试和现场等系统性试验，应用Biolog等检测方法，结合统计分析、模型模拟，研究LID生态滤沟技术对城市路面径流中面源污染物(氮、磷、COD、重金属、油脂类、有毒有机物)的净化过程与作用机理。从水质和水量两方面，重点观测填料组合方式、填料厚度、沟宽、淹没区深度与碳源的投加、植被条件、入流水流及污染物特性、降雨间隔时间以及温度等因素对生态滤沟净化效果的影响，建立净化效果与主要影响因素之间的耦合定量关系及数学模型，探讨数学模型在生态滤沟设计中的应用，并开展实例研究。这对城市面源污染防治、雨洪管理和可持续发展具有重要的科学意义和应用价值。同时，又可有力促进水文学、水力学、生态学、土壤学、环境学等学科理论的交叉、创新和发展。

随着我国城市化进程的加快，城市面源污染控制和雨洪管理的需求日益突出。道路是城市面源污染的关键源区，本项目在分析了国内外相关研究成果的基础上，从水质（浓度去除）和水量（径流削减）两方面，重点研究了生态滤沟系统在不同影响因素（进水污染物浓度、进水水量、运行间隔时间、滤沟宽度、填料种类）对路面径流污染物（包括氮、磷、COD、重金属等）净化效果和径流水量及洪峰削减效果的影响。生态滤沟的水量削减率、污染负荷削减率均在40%以上，削减效果较好。在诸多影响因素中，各因素影响的重要程度从大到小依次为：进水水力负荷、基质种类、进水污染物浓度、基质组合方式、植物种类。通过系统试验（小试、中试和实际工程）与理论分析，建立了生态滤沟净化效果、水量削减效果与主要影响因素之间的关系模型，并基于HYDRUS-1D进行了生态滤沟水分运移模拟和污染物运移模型模拟；根据生态滤沟的入流情况（入流水力负荷、污染负荷等）和目标污染物预期净化效果等，明确了生态滤沟设施主要技术参数（填料组合方式、填料厚度、沟宽、淹没区深度及设计水量等）的设计方法，为生态滤沟这一城市面源污染防治的新型生物工程措施的推广应用提供了科学依据和理论支撑。