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1、初期径流弃流设施 First flush devices目标 Purpose 为了防止例如树叶和其他污染物进入蓄水罐In order to prevent leaves and other contaminants from entering the storage tank 通过过滤改善水质To improve water quality by filtration 有效减轻雨水径流带来的面源污染To relieve the non-point source pollution by runoff 可以有效的减少径流和洪峰流量It can reduce runoff and peak flo
2、w effectively.水敏感目标的效果 Achievement of water-sensitive objectives 水 质：有效净化水体能力。Water quality: Effective Decontamination capability. 水平衡：可以控制水量和减少洪峰流量。Water balance: Can control of water volume and reduce peak flow. 水保持：地下水循环能力较弱。Water conservation: Low effective on groundwater circulation capability.
3、 生 境：对改善生态环境无太大帮助。Habitat: It has little help with environment. 欣赏价值：对城市景观没有帮助。Human perception value: There is no help on urban landscape.简介和实施案例 Description and example for realization 收集的径流必须经过弃流系统，这些弃流系统应安装在与地下相连的落水管处。The collected runoff must pass removal systems, which should be installed near
4、 the down-pipes that connecting to underground system. 大部分弃流装置用细筛过滤水，一小部分水用于保持装置的清洁。Most of the removal devices filter water by fine sieve, a small part of water is used to keep these devices clean. 从流域流出的污染最严重的初期径流会被拦截处理The most polluted runoff from catchment can be intercepted. 这部分冲走污物的水直接排入下水管道或在
5、回灌前排入处理设施中This part of water washed away the dirt directly into the sewer or treatment facilities before recharging.图1 设施应用例子 Figure 1 Application example1 来源source：http:/www.gwp.org/Global/GWP-C Files/First Flush.jpg , 2013-07-20.图2 初期弃流装置的示意图 Figure 2 Schematic diagram of a first flush device2来源so
6、urce：http:/www.gwp.org/Global/GWP-C Files/First Flush.jpg , 2013-07-20.计算过程 Calculation procedure 根据建筑小区雨水利用工程技术规范（GB 50400-2006）公式5.6.4, 5.6.5 According to the formulations 5.6.4, 5.6.5in GB 50400-2006:得设计初期雨水弃流量计算 designed first flush runoff calculation其中whereWi设计初期雨水弃流量 designed first flush remov
7、al quantity（m3） 初期雨水径流厚度 first flush runoff thickness（mm），水面取雨取0 F汇水面积 catchment area (m)当无资料时，可采用2-3mm径流厚度作为屋面初期雨水弃流厚度，5-7mm作为地面初期雨水弃流厚度 If you didnt find any information, you can use 2-3mm as first flush runoff removal thickness of roof and 5-7mm as first flush runoff removal thickness of ground.已
8、知：有一矩形平屋顶建筑,轴线尺寸为36m6m,墙厚240mm.Given：a rectangle flat roof which size are 36m6m, the thickness of wall is 240mm.选择3mm径流厚度作为屋面初期雨水弃流厚度，则设计初期弃水量为：We use 3mm as first flush runoff removal thickness of roof. Then designed first flush runoff is: =10*0.003*(36-0.24)(6-0.24)=6.18设计实例 Design example 该项目于201
9、2年5月建成，针对当地的建筑设计初期弃流装置用于雨水收集系统In May 2012 an Arkitrek Camp team made a first-flush diverter for a rainwater harvesting system on their design for the Mantanani Bunkhouse. Heres how it works. 该建筑顶部面积约为45 m，这意味着1mm的雨水将产生约45公升的水供人们收集。装置容积为35公升，能够接收初期1mm的降雨。这个数字背后没有科学研究，它只是大概的。屋顶是传统的棕榈茅草屋，屋檐是镀锌波纹钢便于收集雨水
10、排到排水沟里。This building has a roof area of approximately 45m which means that 1mm of rain will yield approximately 45 liters of water for collection. The first flush diverter with a volume of 35 liters is designed to divert the first 1mm of each rainfall. Theres no science or research behind this figur
11、e, it just feels about right. The roof is traditional nipah palm thatch with a strip of galvanized corrugated steel at the eaves to collect water neatly into a gutter.图4 沙巴设计案例Figure 4 Design example for Mantanani Bunkhouse 4来源source：http:/ Preferential flow removal device图5优先流法弃流装置示意图 Figure 5 Sche
12、matic diagram of large roof runoff removal device 5来源source：改绘自Prof. Dr.-Ing. W.F. Geiger ,Dr.-Ing. C. Wilhelm, Sustainable Water Management in Urban Areas Rainwater harvesting M, 2002.应用的区域 Application areas 初期雨水弃除最常用的方法The most common way to deal with first flush removal.材料 materials 砖砌Bricked 混凝土
13、现浇、预制或采用成品Cast-in-place concrete, precast concrete or finished products.功能和设计 Function and design 将设计的集雨面的初期径流量优先排入相应容积的储水空间内，再流入收集系统。First to discharge the first flush runoff into corresponding storage space. Then flows into collection system. 所截留的雨水在降雨结束后或由水泵排入污水管道，或逐渐渗入周围的土壤。The interception wate
14、r are pumped into drainage pipe after rainfall or gradually infiltrate into nearby soil.优点 Advantages 简单有效Easy and effective 准确按照要求控制初期雨量It can accurately control first flush rainfall in accordance with the requirements缺点 Disadvantages 汇水面积大时，污染物弃除效率不高，需要较大的池容When catchment is large, the efficacy of
15、 removing pollutant is not high. It need larger space to contain the water.落水管过滤器 Downpipe filter图6落水管弃流装置示意图 Figure 6 Schematic diagram of downpipe device 6来源source：http:/ Application areas 设计针对与地下蓄水罐连接的落水管They are designed for downpipe filters connecting underground storage tank.材料materials 塑料(PP, PE)Plastic(PP, PE) 不锈钢Stainless Steel 铜
