Computational Fluid Dynamics Modeling of Residence Time Distribution in a Field-Scale Horizontal Subsurface Flow Constructed Wetland with Palm Kernel Shell as Substrate

The hydraulic performance of constructed wetlands is often compromised by hydraulic problems. Therefore, the development of an appropriate simulation model to reliably predict how various modifications of bed design and configurations might affect performance will facilitate the design of efficient systems. The aim of this research work is to determine distribution of residence time in a field-scale horizontal subsurface flow constructed wetland with Palm Kernel Shell as substrate. The governing equations of flow in porous media and transport of diluted species were solved using COMSOL Multiphysics 5.3a. The result was validated using experimental data and the model result showed good agreement with a correlation coefficient of 0.99. Alternative wetland designs were assessed for the same flow conditions. The results revealed that a two cell wetland improved short-circuiting flow paths.