A new style of rapid infiltration structure and filter medium composition was designed and optimized.This new style of rapid infiltration pond has a high removal rate of 85% for COD and 90% for SS.Compared with the traditional rapid infiltration pond,it has no obvious increase for the removal rate of COD and SS.The saturated layer provides anaerobic condition for denitrifying bacteria with a long-term water logging status.It increases the removal rate of total nitrogen by nearly 20 percent.Fluorite sand fil...