【摘要】 在示踪剂试验的基础上,利用水力停留时间分布(RTD),探讨了冲击负荷下水平潜流人工湿地的水流规律.结果表明:水平潜流人工湿地在恒定负荷和冲击负荷条件下的实际平均停留时间均大于表观停留时间,混合效应是导致流态偏离理想推流态的主要原因;水力冲击使入流污染物(包括冲击前、冲击中以及冲击后进入的污染物)在系统内部的接触反应时间缩短,其中峰值时间、最短停留时间和实际平均停留时间的相对大小依次均为:恒定负荷>冲击负荷后>冲击负荷前>冲击负荷中;采用基于动态流量的时间变量进行归一化处理后的RTD对人工湿地所处的水力负荷状态、示踪剂投加量等因素并不敏感,表现出稳定的停留时间分布特征,较原始的RTD曲线更能代表冲击负荷条件下人工湿地的特征水流规律.更多还原

【Abstract】 Characteristics of the flow pattern of a horizontal subsurface constructed wetland under shock load condition were studied on the basis of tracer experiments using residence time distribution (RTD) theory for analysis.The results indicated that the mean retention time is longer than the nominal retention time both in constant flow conditions and shock load conditions,which was mainly due to a mixing effect within the wetland system.Shock load reduced the contact time of pollutants entering the constructed wetland before,after and with the shock load.The order of summit time,shortest time and mean retention time was:constant flow conditions>after shock load>prior to shock load>in shock load.The RTD concentration curve,normalized with the time variable  which is based on the dynamic flow,was relatively stable and was not sensitive to hydraulic load and quantity of tracer injection,which indicated that this normalized RTD was more suitable to characterize the flow pattern under shock load conditions than the original RTD.更多还原