Abstract
An integrated risk assessment model for the solid waste landfill was developed. The behaviors of the contaminants from different sources (leakage of leachate through the bottom liner, discharge of the treated leachate to the river, landfill gas) via various media (aquifer, river, air, vegetables, fruits, fish etc.) were described by the equations as simple as possible based on the previous studies. By using this model, the risk of the virtual municipal solid waste landfill was calculated. Benzene, arsenic and dioxin were selected as the representative contaminants. Calculation results showed that the risk of the landfill was extremely smaller than the risk before the landfill is constructed (background risk). The risk derived from the discharge of the treated leachate to the river comprised a large percentage of the risk of the landfill, except the proportion of the risk derived from the landfill gas was large for benzene in the beginning of the landfill operation. Therefore, the difference of bottom liner types (single geomembrane liner and composite liner) had little influence on the risk. Moreover, the sensitivity analysis was conducted for the parameters for landfill property, meteorological condition, aquifer & river properties and life-style of residents. The result showed that the parameters for landfill property (the concentration of contaminants in leachate, the area of the landfill) had a large impact on the increase of the risk.
