潜流式湿地系统停留时间分布实验结果分析

鉴于水力停留时间对人工湿地系统处理效果和构建设计的重要性,通过示踪实验测定了潜流式湿地系统的停留时间分布,结合反应器理论,对实验测定的不同进水流量范围的停留时间响应结果,分别以多釜串联模型以及移位正态分布函数进行拟合,并进一步对系统的水力平均停留时间、系统的流动形态以及非理想性进行了分析和讨论,为湿地系统的水力学优化设计和实际运行提供理论基础和技术参数.

Study of residence time distribution for subsurface flow constructed wetlands

The residence time of water inflow in the constructed wetlands is an important design factor affecting its treatment performance. Series of tracer experiments were performed to study the residence time distribution of the lab scale subsurface flow wetland system relative to predictions of non-ideal flow models. The measured mean residence times were all substantially larger than the theoretical values; the difference increased as the feed rate decreased. The time delay shifted normal distribution model simulation curves represented the experimental results, shown as the residence time distribution density function, much better than the tanks-in-series model. The analyses and discussions of the experimental and simulated mean hydraulic residence times, fluid state in motion and non-ideality of the wetland system have provided important theoretical considerations and technical parameters for optimal design and operation of the relevant constructed wetlands.