In order to analyze the effects of urban sewage sludge applied in sand and loam soil on nitrogen(N) and phosphorus(P) in groundwater,a gradient test design was conducted with 4 treatments of 0(control),2%,4%,6%(rates of sludge application expressed as sludge to soil ration).Different quantity of sewage sludge selected from Beijing Gaobeidian Wastewater Treatment Plant and the compost of Panggezhuang Composting Plant were added in the sand and loam and the soil column models were used to study the release pr...