The Influence of Particle Sizes and Inlet-Outlet Configuration on the Hydraulic Characteristics of Horizontal Subsurface Constructed Wetlands

Abstract

The objective of this study was to evaluate the influence of inlet and outlet location and matrix particle size on the hydraulic efficiency of horizontal subsurface constructed wetlands. A quasi-Two-dimensional model was set up to evaluate its hydraulic efficiency by salt tracer test, and the change of flow state in the system was observed by dye tracer test. Three inlet and outlet settings: Top inlet-bottom outlet, middle inlet-middle outlet and bottom inlet-Top outlet; three particle size distributions are 3 mm, 5 mm and 3/5 mm (one half part 3 mm, the other 5 mm). According to the tracer test, the position of inlet and outlet and the size distribution of matrix have an effect on the hydraulic characteristics of constructed wetlands. Larger substrate size with bottom inlet-Top outlet configuration could improve hydraulic behaviour, improve water treatment efficiency.