| China’s urban scale rapid developed these years, accompanied by the growing population of the city, downtown, residential areas, construction sites and other increases. Overly rapid development, leading to the inner surface of urban keeping the high rate of hardening, poor urban flooding, internal water environment continues to deteriorate. Many areas’ groundwater resources can not be added, had a downward trend, aquatic ecosystems continue to disrupt because of the road hardening rate. Most urban rainwater runoff directly discharged into nearby receiving water, high levels of pollutants in the rain at the same time lead to eutrophication pollution also caused a waste of valuable water resources, human settlements conditions are declining. In addition, China’s per capita water consumption is still below the world average, the waste of water resources is one of the important reasons for this phenomenon still exists. So now desperately need a water treatment technology to effectively deal with Rainwater Runoff which both have multiple effects to facing urban Runoff Pollution and waste, and many other issues. Water treatment technology of constructed wetlands as a rapid development in recent years, it is not only able to buffer the impact of rainwater runoff loads and effective removal of contaminants in rainwater, you can also build tourism which have economic efficiency, and the constructed wetland is simple to run, cheaper maintenance, long service life after building up, and is an appropriate water treatment technology which could applied in the city.In this study, reference to previous rainwater runoff pollutant content information in Lanzhou, Collect Lanzhou Jiaotong University’ ground runoff and roof runoff,detect the pollutants true content of the runoff, data and conclusions drawn at the same time provide a reference for the preparation of water simulation. By TP dynamic adsorption experiments comparing several different substrates constructed wetland,and get each filler adsorption of TP. According to the results, Select the adsorption effect of two kinds of filler, mixing with organic matter, continue the dynamic test with the mix of complex filler, select a suitable wetland complex filler. Application the composite filler in surface-subsurface flow constructed wetland system, adjust the inlet water, the hydraulic load conditions, and verify that the composite effect of filler in the practical application of wetland system, and determine the appropriate hydraulic operating point, provide the theoretical basis for subsequent promotion of constructed wetland. By varying the hydraulic load, simulating rainwater runoff’s short time and large water features, constructed wetland system is studied in greater shock loads affected treatment effect size. Experimental results show that:(1) Actual rainwater runoff have lots of organics, ammonia, total nitrogen, total phosphorus turbidity content. Regardless of roof or rood rainwater runoff,rain began to rain money 0-20 minute which contaminants are in high level, this is the scouring effect of rainwater, late rains, rapidly falling levels of pollutants than initial quality has improved to some extent. 0-20 minutes before the start to rain, contaminants are at a high level, which belongs to the scouring effect of rain, late in the rain, contaminants decreased rapidly, comparing first flush,water quality has improved.(2)According to adsorption of phosphorus,selecte zeolite、fine ceramicite、 coarse ceramicite which have good adsorption. Different proportions of composite fillers of adsorption for phosphorus descending order:90% of the fine ceramsite>90% coarse ceramisite>80% coarse ceramisite>85% of the fine ceramsite>80% of the fine ceramsite>85% coarse ceramisite. Though the desorption characteristics of saturated adsorption filler for phosphorus, selecte 90% fine ceramisite and 90% coarse ceramisite filler for constructed wetland, not only a good performance in terms of adsorption, and adsorption saturation release its low phosphorus proved suitable as constructed wetland filler.(3)In plants-free condition, Mechanism of constructed wetland systems to remove contaminants including sediment adsorption of chemical effect and microbial effect. In the presence of two, good pollutant removal effect in constructed wetlands for rainwater runoff. After the wetland planting reeds,it’s removal rate of pollutants will increased,but the effects is not good, descripting that plants in constructed wetland for removal of pollutants plays a small role.(4)Experimental contrast that system under plants-free state, and three different hydraulic loading of 0.083m3/m2·d、0.125m3/m2·d、0.167m3/m2·d, the surface-subsurface flow constructed wetland systems’ water removal efficiency of pollutants in rainwater runoff simulation. under conditions of 0.125m3/m2·d hydraulic load, 2d hydraulic retention time, stabilized constructed wetland have better removal ability of pollutant,the effluent turbidity removal rate is 89.83%-93.39%, the effluent total nitrogen removal rate is 0.21%-78.24%, the effluent ammonia removal removal rate is 89.08%-91.58%, the effluent CODcr removal rate is 84.61%-88.74%, the effluent total phosphorus removal rate is 82.84%-92.66%.Apart from TN, the quality of treated water could be IV water standards for surface water discharge requirements of the environmental quality standard for surface water(GB3838-2002).(5) The experimental design of dealing with actual rainwater runoff experimental in constructed wetland results show that the system has the advantage of actual rain water treatment capacity,expect for CODcr. Systems for turbidity removal rates of the final effluent can be 94.04%, 93.17%, 93.65%, Total nitrogen removal efficiency of 73.8%, 76.01%, 73.75%, ammonia nitrogen removal rate can reach 90.08%, 88.95%, 89.68%,CODcr removal of 78.33%, 71.01%, 72.19%, total phosphorus removal can be 87.76%, 89.32%, 91.01%.(6) Impact on ammonia nitrogen loading experimental results show that poor impact resistance ability of the wetland system of ammonia nitrogen, 3h, 5h on the ammonia nitrogen removal rate of only 28.81%, 20.41%,5h removal rate even lower.(7) Total phosphorus, CODcr shock loading experimental results show that under the impact load, wetland phosphorus、CODcr removal rate decline, but still has a good removal efficiency, 3h, 5h average removal rate of TP was only 52.51%, 47.19%, the average removal rate of CODcr was only 61.99 percent, 54.32 percent. |
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