Study on Enhanced Measures for Operation of Subsurface Flow Constructed Wetlands in Winter

The subsurface flow constructed wetland was covered with the harvested wetland vegetation for the sake of heat preservation.The influence of the heat preservation technology on the pollutant removal effect of subsurface flow constructed wetland in winter was studied.The results show that the pollutant removal effect can be improved by covering the wetland with harvested vegetation in winter.The average removal rates of TP,NH+4-N and TN in the covered wetland are higher 15.5%,9.7% and 5.0% respectively than that in the control wetland.The frozen earth surface thickness of the covered wetland is much less than that of the control wetland,which indicates that this technology can avoid or reduce the frozen media in winter.