Modeling of the dispersion of pollutants in porous media: Case of a landfill in Brazil

Municipal solid waste (MSW) disposal systems are still a sanitary and environmental problem. The high concentration of toxic substances existing in liquids arising from the decomposition of waste, present a risk to human health and the environment. It is necessary to establish mechanisms to predict leachate dispersion in order to determine possible scenarios and control systems. This work investigates the dispersion of leachate from urban solid waste through saturated soil. The municipal landfill of Jacarezinho in Brazil is the focus of the study. The conceptual model was based on existing data from geology, hydrology, hydrogeology and leachate characterization. The codes MODFLOW and MT3DMS were used and the dispersion of chromium, copper, lead and zinc was simulated. Pollutant mass concentration fields were calculated in 1, 5, 10, 25 and 50 years. The results indicated that the pollutants could reach the Ouro Grande River, in a period of 5 years and the tributary in a period of 1 year of the initial generation of leachate. For the final period of the simulation, the tributary of the Ouro Grande River received copper and lead concentrations that exceeded the maximum values allowed in Brazilian legislation for the watercourse quality standard. It was concluded that the Jacarezinho landfill has the potential to pollute the surrounding soil and groundwater.