Numerical simulation of benzene seepage through cracked compacted mineral liner of municipal waste landfill

Abstract

: This paper contains the results of numerical simulation of benzene migration, pollutant typical for landfill leachate, through the bottom compacted clay liner of municipal waste landfill. The FEFLOW, DHI software was used in the numerical calculations for four tested clays of various plasticity, compacted according to PN-B-04481:1988 and ASTM D698-12e2 and subjected to three cycles of drying and rewetting. The plasticity of the tested clay materials was determined by standard methods and classified according to the Unified Soil Classification System, ASTM D2487-11. Saturated hydraulic conductivity of the tested compacted clays was determined by the laboratory falling head permeameters for compacted soils, with agreement to ASTM D5856-95. Saturated hydraulic conductivity of the tested substrates after three cycles of shrinkage and swelling was measured by the falling and constant head laboratory permeameter. The sand box and pressure chambers with ceramic plates were used to determine the water retention curve parameters in the range of 0–15 bar. The obtained results showed the influence of cyclic shrinkage and swelling of clays on leachate seepage, triggering benzene migration, through the cracked compacted bottom liner.