The test on treating pollution water of Handan by using a two-grade series constructed wetland system.The results show that the constructed wetland has a purifying effect perennial,the removal rate of COD,TN and TP are 25%-65%,29%-94% and 30%-80%.Under the same hydraulic loading,the wetland with relatively better growing plants demonstrated higher pollutants removal efficiency than that with relatively worse growing plants.The removal effect and stability of subsurface flow wetland is better than surface constructed wetland's.The removal effect showed certain seasonal variation,the rate in summer better than in cold winter.

The test on treating multiple pollution water of Handan has been continuing for a long-term by using the composite constructed wetland system,in which the aquatic plants with stain resistance are selected.The results show that the constructed wetland has a purifying effect perennial,the removal rate of BOD,TN and TP are 25～65%,27-84% and 30-80%,respectly.The removal effect and stability of subsurface flow wetland is better than surface constructed wetland's.The influence factors of removal effect are temperature,plant growth conditions and matrix,and the changing of temperature is the main factor.