Efficiency of Subsurface-flow Constructed Wetland for Pretreatment of Raw Water

In order to improve the inflow water quality and mitigate the loads of water treatment processes,a subsurface-flow constructed wetland was used to pretreat the raw water of waterworks.Using the Songhua River as the raw water source,the removal of turbidity,CODMn,UV254,TN and NH+4-N in the subsurface-flow constructed wetland was investigated.The results show that when the inflow rate is 0.8 m3/d and the hydraulic retention time(HRT) is 1.5 d,the average removal rates of turbidity,CODMn,UV254,TN and NH+4-N in the constructed wetland are 93.71%,43.19%,17.69%,49.15% and 48.92% respectively.The subsurface-flow constructed wetland has high treatment effect and stable operation.It can reduce the loads of water treatment processes.