Research on Nitrogen Removal Efficiency from Sewage by Different Processing Combined Constructed Wetland Systems

Based on the units of anaerobic sedimentation reservoir,vertical subsurface flow wetland,horizontal subsurface flow wetland,surface flow wetland and ecological landscape reservoir,these four different processing combined constructed wetland systems were established and applied for removing nitrogen from sewage. The one year continually experimental monitoring showed that different processing combined constructed wetland systems achieved different nitrogen removal efficiency. On the basis of subsurface flow wetland unites,the established CW4 system had highest removal efficiency for ammonia and total nitrogen,with a percentage of 52. 23% ～ 82. 46% and 38. 72% ～ 88. 46% respectively. However,the CW3 and CW1 systems achieved the lowest removal efficiency for ammonia and total nitrogen,33. 46% ～ 67. 42% and 12. 32% ～ 61. 43% respectively. Additionally,different seasons greatly affected all the constructed wetland systems removal efficiency for ammonia and total nitrogen. The systematically and comparatively experimental research proved that the based vertical and horizontal subsurface flow constructed wetland system has higher removal efficiency for nitrogen and better application prospect.