PREDICTION OF CONTAMINANTS MIGRATION AT UNLINED LANDFILL SITES IN AN ARID CLIMATE - A CASE STUDY

摘要

Landfilling of municipal solid waste (MSW) is associated with the generation of leachate that is highly contaminated. Contaminant migration from disposal areas to groundwater poses a threat to the environment and the human health. This study examined the contaminant migration at a landfill site in Kuwait. The migration characteristics of contaminants were analyzed using advanced computing systems to predict the long-term plume concentration in underlying soils and aquifers located directly below the final waste layer. Mathematical models of contaminant migration were applied to existing landfill sites using MIGRATEv9 computer program to illustrate the scope and extent of soil and water contamination. Two main cases were modeled as follows: (1) water table is deep below landfill and (2) water table is rising into the landfill. The models included advective-dispersion, and buried landfills systems. The comparison between models results suggested that vertical Darcy velocity had a significant impact on migration behavior of contaminants. The concentration was increased by 24.5% by increasing the vertical Darcy velocity from 0.005 to 0.009 m/year. Advection-dispersion models and water rising models with fixed top boundary and aquifer bottom boundary at 2 and 3.5 m showed almost the same migration behavior. In addition, models of buried landfill system where water table was 5 m from ground surface produced a maximum contaminant concentration of 17 630 mg/L after 25 years at 5 m depth.