下凹式绿地对降雨径流及其污染物削减作用研究

发布时间：2018-01-09 02:20

本文关键词：下凹式绿地对降雨径流及其污染物削减作用研究　出处：《苏州科技学院》2015年硕士论文　论文类型：学位论文

【摘要】：随着城市化进程的加快以及人们生活水平的提高,城市规模不断扩大,人口密度不断增加,大量透水地表被不透水地表取代导致地表雨水径流量增大,洪峰流量增大,径流峰值提前,径流系数增大;同时人口密度的不断增大导致污染物大量积累,这些污染物经过雨水冲刷通过城市雨水管网排入水体造成严重的非点源污染,使受纳水体的水质严重变差。城市绿地作为城市生态系统的重要组成部分,不仅有助于削减降雨径流,而且对降雨径流污染物的去除有很好的效果。本论文针对苏州地区实际情况,通过实验研究,确定下凹式绿地作为降雨径流及其污染物削减的综合控制利用措施。本文首先对苏州的历史降雨事件及径流水质等特征规律进行了调查,并依据课题组对苏州地区降雨径流水质的分析,为配置实验用水提供理论依据;其次对苏州地区绿地渗滤层土壤进行改良,通过对城市绿地系统和降雨系统进行模拟,研究了城市绿地系统对降雨径流和径流污染物的去除效果;最后利用SWMM模型对研究区域采用下凹式绿地前后径流和径流污染物削减效果进行对比分析,为苏州市绿地规划和建设提供理论依据。本文试验结论如下:1.三种类型绿地系统对降雨径流有较好的削减效果,原土回填下凹式绿地、经陶粒改良的下凹式绿地、经沸石改良的下凹式绿地在不同降雨重现期条件下对降雨径流的削减效果一致;三种类型下凹式绿地系统均能对小降雨强度的降雨事件发挥较好的效果。降雨重现期为2年一遇,随着降雨时间的增加,三种类型下凹式绿地系统对雨水径流削减率逐渐提高。2.三种类型下凹式绿地系统对COD、SS、TN、TP等污染物的平均去除率都有随降雨重现期的增加而逐渐下降的趋势;三种类型下凹式绿地系统在降雨过程中对COD、SS、TN、TP等污染物的去除率都有随降雨时间逐渐下降的趋势;降雨径流污染物浓度分别为低、中、高时,三种类型下凹式绿地系统对各污染物去除率有随着降雨径流污染物浓度上升而呈现逐渐增加的趋势;经陶粒改良的下凹式绿地系统对TP具有很好的去除效果,经沸石改良的下凹式绿地系统对TN具有很好的去除效果。3.利用SWMM模型对研究区域进行模拟分析,将平式绿地改为下凹式绿地后可以有效降低地表径流总量、削减峰值流量、缩短径流持续时间及延迟径流峰值时刻。
[Abstract]:With the acceleration of urbanization and the improvement of people's living standards, the urban scale is expanding and the population density is increasing. A large number of permeable surface is replaced by impervious surface, which results in the increase of surface Rain Water runoff. Hong Feng discharge increased, runoff peak advance, runoff coefficient increased; At the same time, the increasing population density leads to a large amount of pollutants accumulation, these pollutants through Rain Water washed through the urban rainwater pipe network into the water, resulting in serious non-point source pollution. As an important part of urban ecosystem, urban green space is not only helpful to reduce rainfall runoff. And the removal of runoff pollutants has a good effect. This paper is based on the actual situation in Suzhou, through experimental research. To determine the concave green space as a comprehensive control and utilization measures for rainfall runoff and its pollutant reduction. Firstly, the characteristics of historical rainfall events and runoff water quality in Suzhou were investigated in this paper. According to the analysis of rainfall runoff water quality in Suzhou area, the theoretical basis is provided for the allocation of experimental water. Secondly, the soil of leachate layer in Suzhou area was improved, and the removal effect of rainfall runoff and pollutants from urban green space system was studied by simulating urban green space system and rainfall system. Finally, SWMM model was used to compare the effect of runoff and runoff pollutant reduction before and after using concave green space in the study area. The experimental results are as follows: 1. The three types of green space system have good effect on rainfall runoff reduction, and the original soil backfill concave green space. The concave green space improved by ceramsite and the concave green land modified by zeolite have the same effect on the reduction of rainfall runoff under different rainfall recurrence periods. Three types of concave green space system can play a better effect on rainfall events with small rainfall intensity. Rainfall recurrence period is once in 2 years, with the increase of rainfall time. The reduction rate of Rain Water runoff was gradually increased by three types of concave green space system. The average removal rate of TP and other pollutants decreased with the increase of rainfall recurrence period. The removal rate of pollutants such as COD SSN TNN TP in three types of concave green space system decreased gradually with rainfall time. When the concentration of pollutants in rainfall runoff is low, middle and high, the removal rate of each pollutant in three types of concave green space system has the tendency of increasing gradually with the increase of the concentration of pollutants in rainfall runoff. The concave green space system improved by ceramsite has a good removal effect on TP. Zeolite modified concave green space system has a good removal effect of TN. 3. The SWMM model is used to simulate the study area. Changing flat green space into concave green space can effectively reduce the total surface runoff, reduce the peak flow, shorten the duration of runoff and delay the peak time of runoff.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52;TU985.12

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