The Purification Potentials of Different Soil with Different Depths to Leachate from Li Keng Landfill in Guangzhou City
不同质地土壤对填埋场渗滤液的吸收净化效能

Soil with different texture(sandy soil,clay soil and loamy soil)were used to attenuate leachate from Li Keng landfill in Guangzhou city.They were employed to pack columns of different depths of 0.3,0.5 and 1.0m,soil columns were respectively treated by growing Cynodon dactylon and not growing C.dactylon. Leachate was drained into the soil columns each day for 8 weeks.The percolated leachates were collected weekly and their properties were analyzed.It was revealed that the purification efficiency of all soil columns decreased as the soil depth decreased,growing plant(C.dactylon)could improve the efficiency.Clay soil and loamy soil had higher capacity to remove COD and ammonia,clay soil had the highest ability in absorption of P,and the metal contents of leachate percolated from the clay soil columns were lower than that of loamy soil.However,loamy soil had significantly higher ability to absorb metal in leachate,especially for heavy metals.Toxicity test of percolated from soil columns in the different stages indicated that the removal of toxicity of the same depth soil with different textures showed significantly difference(P<0 01),but that of the 1.0m columns with different textures displayed significantly difference(P<0 01).