Investigation of Subsurface Flow Constructed Wetland Designs

Abstract

Results of a bench-scale model investigation of the dispersion impact on Subsurface Flow ConstructedWetland(SFCW) designs are presentedin this arti cle. The research involved determining the dispersion number as interstitial velocity, a function of aspect ratio and flow rate, was varied. The range of dispersion numbers foundwas from 0.107 to 0.345. Results indicatedthat as the aspect ratio is decreased below 2:1, increased dispersion occurs. Additionally, an increase in dispersion number with increasing flow rate for larger aspect ratios (6:1, 3:1, 2:1) was revealed. Interstitial velocity was shown to control dispersion number for higher flow rates; however, aspect ratio controlledthe dispersion number when the ratio was reduced below 2:1. This research provides a valuable tool intended for estimating the dispersion impact when applying alternative models to the design of SFCWs.