수리지질학적으로 불균질한 매립지반 내에서의 침출수 이동에 대한 Monte-Carlo 시뮬레이션

Abstract

The transport of landfill leachate in the subsurface formations of unlined landfill sites is considered. The objective of this study is to assess impacts of heterogeneities on the leachate transport and is accomplished by examining the results from a series of Monte-Carlo simulations. The landfill system simulated in this study is hypothetically represented with spatial variability for the hydrogeological parameter. To assess the transport of leachate through random hypothetical hydraulic conductivity(K) fields generated using geostatistical input parameters, a saturated flow model is linked with a contaminant transport model. Point statistics values such as mean, standard deviation, and coefficient of variation of the concentration were obtained from 100 Monte-Carlo trials for various degrees of heterogeneity ranging from homogeneous to highly heterogeneous. Results of point statistics show that the distribution of hydraulic conductivity in the landfill site proves to be an important parameter in controlling leachate concentrations. The variability in the leachate concentration for different realizations of a heterogeneous K-field increases as K-heterogeneity and the distance between source and monitoring well increase. Consideration of anisotropic heterogeneities represented by correlation length in K-field does not show any apparent impacts.