【作者】 李亮；

【导师】 柴宏祥；

【作者基本信息】 重庆大学 ， 市政工程， 2016， 硕士

【摘要】 长期以来,传统的城市建设模式使得城市水系格局、水生态系统遭到了严重破坏。低影响开发旨在通过分散的,小规模的源头控制来达到对暴雨所产生的径流和污染的控制,使开发地区尽量接近于自然的水文循环。雨水作为景观水体的补水来源,可节约淡水资源,削减年径流总量,减少中小型降雨带来的面源污染。采用雨水作为补充水源,符合绿色建筑评价标准的非传统水源补充景观水体的要求,同时也提高了景观水体水质保障的难度。采用折流式湿地系统构建高效的水质净化生态系统,可达到水生态修复的目的,实现区域良性水文循环。研究了景观水体的水量平衡设计和景观水体对径流雨水的调蓄能力;开展了蓄雨设施雨水水质变化规律的试验研究,并对其污染成因进行了分析;开发了折流式湿地循环处理景观水体试验装置,分别开展了湿地服务比、喷泉启闭、循环处理周期对景观水体水质影响。主要研究内容与结论如下:(1)水量平衡设计以月为时间跨度逐项计算景观水体流入项、消耗项,并编制水量平衡计算表格,确定资源化利用及补水方案。以芝加哥雨型进行降雨时程分配,利用等流时线法模型模拟地表径流过程,有限差分法计算景观水体的进出水流量过程线。以重庆市某建筑小区为例,其景观水体面积574m2,占小区面积的1/87,重现期2年的2h降雨情形下景观水体的雨水调蓄能力:景观水体正常水深1m,降雨时开启放空管,景观水体可延时洪峰7min,峰值流量削减35.1%;降雨前排空景观水体设施,降雨时开启放空管,景观水体可延时洪峰31min,峰值流量削减79.7%。(2)开展不同条件下蓄雨设施雨水水质变化规律的试验研究,四种条件分别是初期雨水、后期雨水、放置陶粒雨水、种植植物雨水。2015年7月22日蓄集初期雨水COD、TN、NH3-N、NO3-N和TP初始浓度分别为35.90mg/L、1.57mg/L、0.26mg/L、0.23mg/L和0.08 mg/L。水质监测第14天,蓄集雨水已出现藻类爆发现象,叶绿素a浓度高达57.46 mg/m3。叶绿素a浓度与氮磷比相关系数R2=0.73。至第42天,各水质指标均已超出地表水V类水体标准限值。八个月后COD和TN浓度分别高达84.17mg/L、7.45mg/L。蓄集的后期雨水水质变化规律与初期雨水相似。放置陶粒的雨水污染物浓度初期有所下降,后期逐渐上升,但污染程度比初、后期雨水较轻。种植植物蓄集雨水各污染物浓度总体呈下降趋势。八个月后COD、TN、NH3-N、NO3-N和TP浓度仅为同时期初期雨水的22.5%、11.4%、44.6%、53.3%和10.6%。叶绿素a浓度始终低于10 mg/m3,未监测到藻类爆发现象。不同蓄雨设施水体水质优劣程度(以总氮、叶绿素a计):初期雨水>后期雨水>放置陶粒雨水>种植植物雨水。(3)景观水体循环处理周期为3d,每天喷泉定时开放四个小时,湿地与水景设施面积比为2/15、1/15时,且进水水质劣于地表水V类水标准,装置运行一周时间,水质可达到地表水IV类水水质标准。景观水体平均浊度为0.87,平均叶绿素a浓度1.74 mg/m3。喷泉启闭对比试验结果表明,喷泉提升复氧效果明显。喷泉开启总体上有利于污染物的去除,尤其对氨氮去除效果明显。当湿地循环处理周期由2d增加到7d时,即湿地进水负荷由3.8 m3/(m2·d)降低至1.1 m3/(m2·d)时,COD、TN、NH3-N和TP的去除率分别由47.8%、35.0%、42.3%和71.0%提升至75.6%、46.1%、65.7%和87.5%,出水各指标均满足地表水IV类水质标准。相同的处理时间(7d)内,不同循环周期下各污染物的去除率没有显著的差别。总体来看,循环周期为3d时污染物去除率略优于其他周期。通过理论分析及试验研究得出了适用于建筑小区景观水体设施水量控制及水质保障的设计、运行维护方案,以期为后期的工程实践应用提供参考。景观水体设施可通过合理的水量平衡设计和运行管理制度有效地实现径流总量和峰值流量削减的目的。折流式湿地循环处理保障景观水体水质,建议湿地面积占水域面积1/15-2/15;喷泉每天定时开启四个小时;5月至10月循环处理周期为3d,11月至次年4月,循环处理周期为5-7d。更多还原

【Abstract】 For a long time, the pattern of urban water system and water ecosystem has been severely damaged by the traditional urban construction mode. Low impact development aims to achieve the control of runoff and pollution from the storm by decentralized, small-scale source control, so that the development of the region as close to the natural hydrological cycle. Using rainwater as a supplemental source of landscape water can save fresh water resources, cut the total annual runoff and reduce the non-point source pollution caused by small rainfall. Using rainwater as a supplemental source will meet the green building evaluation standard, which requires using non traditional water source to supplement landscape water. It also improves the difficulty of the water quality assurance of the landscape water. The use of the baffled flow wetland system to construct an efficient water purification system can achieve the purpose of water ecological restoration.The water balance design and runoff pondage action of landscape water were analyzed; the water quality change of the micro rain storage facility was monitored and the pollution causes were analyzed; a baffled flow wetland- landscape water test device was developed, the factors affecting the water quality of landscape water body were discussed, such as the wetland area, the opening and closing of fountain, the cycle time and so on. The main research contents and conclusions are as follows:(1) Inflow and outflow of landscape water was calculated by month in the water balance design, and water balance calculation form was drawn. The rainfall was distributed according to Keifer&Chu rainfall pattern’s principle, the inflow and outflow hydrograph was calculated by using finite difference method. Taking a construction area of Chongqing city as an example, the area of landscape water was 574 m2, accounting for the construction area of 1/87, 2 hours rainfall under the return period of 2 years, landscape water runoff pondage action: when landscape water normal depth was 1m before the rainfall, open the escape pipe, landscape water can delay strom peak 7 min and reduce the peak flow 35.1%; before the rain, emp tying landscape water facilities, open the escape pipe, landscape water can delay strom peak 31 min and reduce the peak flow 79.7%.(2) Experimental study on the change law of rainwater quality in rainwater storage facilities was carried out, the four conditions were the initial rainwater, the latter rain, ceramic rain, plant rain. On July 22, 2015, the concentrations of COD, TN, NH3-N, NO3-N and TP respectively were 35.90 mg/L, 1.57 mg/L, 0.26 mg/L, 0.23 mg/L, and 0.08 mg/L in initial rainwater. On the fourteenth day, there was an outbreak of algae, and the chlorophyll a concentration was 57.46 mg/m3. The correlation coefficient between the concentration of chlorophyll a and N/P ratio was 0.73. By the forty-second day, the water quality worse than the V class standard of surface water quality. After eight months, the concentrations of COD and TN were as high as 84.17mg/L and 7.45mg/L, respectively. The change law of water quality in the later stage was similar to that in initial rainwater. The concentration of the pollutants of the ceramsite rainwater was overall upward trend, but the concentration of pollutants was lower than that of the initial rainwater. The concentration of pollutants in the plant rainwater was basically decreased. Eight months later, COD, TN, NH3-N, NO3-N and TP concentrations were only 10.6%, 11.4%, 44.6%, 53.3% and 22.5% of the initial rainwater in the same period. The chlorophyll a concentration was always lower than 10 mg/m3, and the phenomenon of algal bloom was not observed. Q uality of water quality in different storage facilities(with total nitrogen and chlorophyll a): initial rainwater > late rainwater > ceramsite rainwater > plant rainwater.(3) Landscape water processing cycle was 3d, every day the fountain is open four hours. When the area ratio of wetland and water facilities were 2/15, 1/15, and the influent water quality was inferior to the V class standard of surface water quality, the device run a week, water quality can reach the IV class standard of surface water quality. The average turbidity of landscape water was 0.87, and the average chlorophyll a concentration was 1.74 mg/m3. The comparison test results show that the reoxygenation effect of fountain is obvious. Overall, fountain opening was conducive to the removal of pollutants, especially the removal of ammonia nitrogen increased significantly. When the processing cycle increased from 2d to 7d, that is wetland influent load was reduced from 3.8 m3/(m2·d) to 1.1 m3/(m2·d), COD, TN, NH3-N and TP removal rate respectively by 47.8%, 35.0%, 42.3% and 71.0% up to 75.6%, 46.1% and 65.7% and 87.5%, the effluent indexes meet the surface water class IV water quality standards. There was no significant difference in the removal rate of the pollutants in the same treatment time. Overall, the removal rate of pollutants was slightly better than other cycles when the processing cycle was 3d.Theoretical analysis and experimental study have been applied to the design, operation and maintenance of water quality control and water quality maintenance of landscape water in the construction area, in order to provide reference for the later practical application. Landscape water facilities can achieve the purpose of reducing the total runoff and peak flow through the rational design and operation management system. The proposed design parameters of landscape water facilities: wetland area accounts for 1/15-2/15 of water area; fountain regularly open every day; May to October, the processing cycle is 3d, November to April, and the processing cycle is 5-7d.更多还原