Chen(2004)improvedtheapplicationoftraditionalconstructedwetlandsinorder to process high-concentration household wastewater. The pilot scale system was designed for two-stage processing, including horizontal biofilters for aeration and subsurface-flow constructed wetlands. The total removal rate for water quality indicators such as biological oxygendemandandsuspendedsolidswasabove73%ontheaverageafterinitialprocessing. Thecosttobuildatwo-stageconstructedwetlandwasone-sixthofatraditionalwastewater treatment plant and the yearly operational costs were reduced to one-third.