Natural Attenuation Process of NH_3-N in Aged Leachate Leakage Under the Salt Water Condition

Landfill is predominated MSW disposal process in China,and most of landfills located in the shoaly land without proper liner system due to the lack of the construction fee in the coastal region.The mitigation of leachate under the saltwater condition is something special due to the seawater intrusion.NH4+-N in leachate is in a high concentration in the entire landfill stabilization process,and understanding the mitigation of NH4+-N in the salt water condition will be important for the pollution control from landfill.Sand-box model facility was applied to simulate the migration and transportation process of NH4+-N from aged leachate,which was designed based on a working Landfill in Shanghai.It was found that NH3-N preferred to diffuse in horizontally direction,compared to that in the vertical direction.The diffusion rate decreased as the distance extended.The transportation process of carbon substances in the aged leachate is lower than that of N substances,and more carbon substances accumulated in the area near to the leaking point.The diffusion rate of the other N types in aged leachate,such as NO3-,NO2-,is also lower than that of NH4+-N.Therefore,NH4+-N could be one of the dictators for the leachate leakage from landfill.