Comparative Study on Sewage Purification by Two Integrated Constructed Wetlands

Down flow-up flow constructed wetland and down flow-down flow constructed wetland were used to treat domestic sewage.The water qualities were measured to determine the effect of the wetland.The results showed that the down-flow and up-flow constructed wetland was suitable to be operated under a low HLR[0.6m3/(m2·d)],the wetland performed very well in five days in a row.The removal efficiencies of COD,TP,NH4+-N,and TN were 75%~95%,65%~85%,45%~80%,and 45%~80%,respectively.The downflow-downflow constructed wetland can work pretty well while under the high HLR[1.2m3/(m2·d)],the removal efficiencies of COD,TP,NH4+-N,and TN were 70%~95%,40%~85%,50%~90%,and 50%~80%,respectively.Compared to the downflow-upflow constructed wetland,the downflow-downflow constructed wetland is more suitable for the oxygenation and the removal of COD and NH4+-N.This article offered information and references for practical application of constructed wetland.