表面流—潜流人工湿地系统处理城市雨水的实验研究

发布时间：2018-01-10 18:08

本文关键词：表面流—潜流人工湿地系统处理城市雨水的实验研究　出处：《兰州交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：我国的城市规模这些年来飞速发展,伴随而来的是我国城市中人口不断增加,城市商业区、住宅小区、建设工地等随之增加,过于快速的发展,导致我国城市内地面硬化率居高不下,城市透水能力差,内部水环境持续恶化,很多地区地下水资源得不到补充,均有下降趋势,水生态系统也因为路面的硬化率提高而遭到不断破坏,大部分城市将雨水径流直接排放入附近的受纳水体,高污染物含量的雨水在导致水体富营养化污染的同时,还造成宝贵水资源的浪费,人居环境条件也日趋下降。另外,我国人均用水量仍不及世界平均水平,水资源的浪费问题也是造成这一现象持续的重要原因之一。所以现在迫切需要一种能够对雨水径流进行有效处理且兼具多重功效的水处理技术来应对城市雨水污染和浪费等诸多问题。人工湿地作为近些年来高速发展的水处理技术,其不仅能够缓冲暴雨径流的冲击负荷,有效去除雨水中污染物,还可以建成景观旅游等,兼备经济效益,且人工湿地建成后运行简单,维护便宜,使用寿命较长,是一种适宜在城市中应用的水处理技术。本实验中,参照兰州地区已有的降雨雨水径流污染物含量资料,收集兰州交通大学内地表径流、屋面径流,检测其中污染物真实含量,在得出数据及结论的同时为模拟实验用水的配制提供参考。通过对TP的动态吸附实验比较了几种不同的人工湿地基质,得到各基质对TP的吸附效果,并根据实验结果,选择吸附效果较好的两种基质与有机质按一定质量比例进行掺和,用掺和后的复合基质继续进行动态吸附试验,选择出一种适合人工湿地的复合基质。在表面流-潜流人工湿地系统中应用选出的复合基质,调整不同的进水水量、水力负荷条件,验证该种复合基质在湿地系统中的实际应用效果,并确定合适的水力工况点,为后续人工湿地的推广提供理论依据。通过改变水力负荷,模拟暴雨径流时间短、水量大的特点,研究了人工湿地系统在较大冲击负荷情况下处理效果受到影响的大小。实验结果表明:(1)实际雨水径流中有机物、氨氮、总氮、总磷含量较多,浊度较大。雨水径流无论屋面雨水还是道路雨水,在开始降雨的前0~20分钟,其中污染物含量均处于较高水平,这属于雨水的冲刷效应,在降雨后期,污染物含量迅速下降,相比初期雨水水质有一定改善。(2)实验中所选择的单一基质对磷的吸附效果较好的基质为沸石、细陶粒、粗陶粒,不同配比的复合基质对磷的吸附效果由大到小依次为90%细陶粒90%粗陶粒80%粗陶粒85%细陶粒80%细陶粒85%粗陶粒。通过基质吸附饱和后对磷的解吸特征来看,选作人工湿地基质的90%细陶粒、90%粗陶粒不仅在吸附方面有良好的性能,而且其吸附饱和后对磷的释放率低,证明适宜作为人工湿地基质。(3)无植物条件下,人工湿地系统是去除污染物机理包括沉淀吸附的物理化学作用、微生物作用,这两种作用都可以正常发挥作用,无植物时湿地对雨水径流中污染物有较好的去除效果。湿地系统种植芦苇后,湿地系统对各类污染物的去除率均有一定的提高,但提高程度一般,说明植物在人工湿地对污染物的去除中发挥的作用较小。(4)实验对比系统在无植物状态下,种植芦苇的状态下后0.083m3/m2·d、0.125m3/m2·d、0.167m3/m2·d三种不同水力负荷下对表面流-潜流人工湿地系统对进水模拟雨水径流中污染物的去除效果,结果表明,人工湿地植物对污染物的去除有一定的帮助,但效果不明显,在水力负荷为0.125m3/m2·d,水力停留时间为2d的条件下,稳定后的人工湿地对污染物去除效果理想,系统出水浊度去除率为89.83%-93.39%,出水总氮去除率为70.21%-78.24%,出水氨氮去除率为89.08%-91.58%,出水CODcr去除率为84.61%-88.74%,出水总磷去除率为82.84%-92.66%。处理后的水质除了总氮以外,其他几项可达到《地表水环境质量标准》(GB3838-2002)中地表水排放要求的IV类水质标准。(5)本实验设计的人工湿地系统在处理实际雨水径流的实验结果表明,该系统具有良好的实际雨水处理能力,CODcr的去除效果相比于模拟实验有所下降。系统对浊度的最终出水去除率可以达到94.04%、93.17%、93.65%,总氮去除率为73.80%、76.01%、73.75%,氨氮去除率可以达到90.08%、88.95%、89.68%,CODcr去除率为78.33%、71.01%、72.19%,总磷去除率可以为87.76%、89.32%、91.01%。
[Abstract]:Our city the size of these years of rapid development, is accompanied by the increasing population in the city of our country, city commercial district, residential, construction sites and other increases, development too fast, resulting in China's city ground hardening rate is high, the city water is getting worse, the water environment continues to worsen, a lot of groundwater resources are not replenished, had a downward trend, the water ecosystem because of road hardening rate increased by continuous destruction, most of city rainwater runoff directly discharged into nearby water pollution, high content of water in the lead to eutrophication pollution at the same time, also caused the precious water. Waste, human settlements conditions have gradually decreased. In addition, China's per capita consumption is still less than the world average, waste of water resources is the cause of this phenomenon continued to one of the reasons. There is an urgent need to a runoff water treatment technology and effective treatment and both multiple functions to deal with city rainwater pollution and waste problems. As the artificial wetland water treatment technology of high-speed development in recent years, which not only can buffer the impact load of storm runoff, the effective removal of pollutants, but also built landscape tourism, and economic benefits, and the artificial wetland after the completion of simple operation, cheap maintenance, long service life, is suitable for the city in the application of water treatment technology. In this experiment, according to the Lanzhou area has been the rainwater runoff pollutant content data collection, LanZhou JiaoTong University the surface runoff, roof runoff, the real pollutant detection the content, provide a reference for the preparation of simulated experimental water while the data and conclusion. Through the dynamic adsorption experiment than on TP Artificial wetland matrix is different, the matrix effect on the adsorption of TP, and according to the experimental results, the selective adsorption effect of two kinds of matrix and good organic admixture according to a certain mass ratio, composite matrix mixture on dynamic adsorption test, select a composite matrix suitable for artificial wetland in the selected application. The surface flow subsurface constructed wetland system in the composite matrix, adjust the influent water, hydraulic loading conditions, verify the application effect of the composite matrix in the wetland system, and determine the appropriate operating point of water stress, provide a theoretical basis for the subsequent promotion of artificial wetland. By changing the hydraulic loading. Simulation of storm runoff characteristics of short time, a large amount of water, the artificial wetland system is affected by the treatment effect in the larger impact load case size. Experimental results show that: (1) the actual rain Organic matter, ammonia nitrogen in runoff, total nitrogen, total phosphorus content more, turbidity. Rainwater runoff regardless of roof rainwater or road rainwater, in 0~20 minutes before the start of rainfall, the pollutants are at a high level, which belongs to the scouring effect of rainwater, in the later stage of rainfall, the pollutant content decreased rapidly, compared with the initial rainwater quality improved. (2) a single matrix selected in the experiments the effect of phosphorus adsorption on zeolite matrix is good, fine aggregate, coarse aggregate, matrix composite with different ratio of effect of P adsorption followed by 90% fine ceramsite 90% crude ceramsite 80% crude ceramsite 85% fine ceramsite 80% fine ceramsite 85% thick ceramsite. Through the matrix after adsorption desorption characteristics of phosphorus, 90% fine ceramsite selected for constructed wetlands, 90% thick ceramsite not only has good performance in adsorption, and its adsorption on phosphorus release rate is low, that Suitable for constructed wetlands. (3) no plant under the condition of artificial wetland system is the pollutant removal mechanism including the physical and chemical effects, precipitation adsorption of microorganisms, these two effects can play a role in the normal, no plant pollutant runoff in the wetland has a good removal effect. After planting reed wetland system, wetland the system of all kinds of pollutants removal rate were improved to some extent, but the degree of improvement, indicating that the effect of small plants play in artificial wetland for removal of pollutants in. (4) experimental system in plant condition, planting reeds under the condition of 0.083m3/m2 - D, 0.125m3/m2 - D, 0.167m3/m2 - D three under different hydraulic loadings on the surface flow and subsurface flow constructed wetland system on the removal effect of pollutants in stormwater runoff simulation results show that the artificial wetland plants on pollutants removal have some help Help, but the effect is not obvious, when the hydraulic load is 0.125m3/m2 - D, the hydraulic retention time is 2D, the removal effect of pollutants in the ideal artificial wetland in the stable system, the turbidity removal rate was 89.83%-93.39%, the effluent total nitrogen removal rate was 70.21%-78.24%, the effluent ammonia removal rate was 89.08%-91.58%, the effluent CODcr removal rate was 84.61%-88.74% the TP removal rate was 82.84%-92.66%., the water quality after treatment in addition to total nitrogen, several other can achieve "surface water environmental quality standard" (GB3838-2002) in surface water discharge requirements of water quality standard IV. (5) the experimental design of artificial wetland system in treatment of stormwater runoff. The experimental results show that the system the rain has practical good processing ability, compared to the CODcr removal effect in simulation experiment decreased. The final effluent turbidity removal rate can reach 94.04%, 93.17%, 93.65%, The total nitrogen removal rate is 73.80%, 76.01%, 73.75%, ammonia nitrogen removal rate can reach 90.08%, 88.95%, 89.68%, CODcr removal rate is 78.33%, 71.01%, 72.19%, total phosphorus removal rate can be 87.76%, 89.32%, 91.01%.

【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X52;X703

【参考文献】