A Review of the Influence of Design Parameters on the Performance of Constructed Wetlands

Abstract

This study reviews the influence of wetland design criteria (Kickuth equation, area sizing, first order kinetics) and operation parameters (hydraulic and influent loading) on pollutant removal (organics, solids, nutrients and coliforms) in both subsurface and surface flow systems. Results showed that despite high removal efficiency reported for most wetlands, residual concentrations for BOD are frequently higher than those predicted based on the 95 percentile first-order Kickuth design equation. Also correlation results indicate that hydraulic and pollutant loading strongly influence wetland performance for organic removal (BOD, COD). In all cases, removal generally decreases as loading increases. Hydraulic loading was not found to correlate with nutrient removal. Overall, it can be concluded that organic removal can be modeled better compared to nutrient in treatment wetlands. Since removal of solids and coliforms are not primarily influenced by the key design parameters, it is expected that they will fit into any design model developed. Keywords design criteria; hydraulic loading; removal. DOI: 10.3329/jce.v25i0.7237Journal of Chemical Engineering, IEB Vol. ChE. 25, No. 1, December 2010 pp.29-42