Mass transport of organic contaminants through a self-sealing/self-healing mineral landfill liner

Abstract

The self-sealing/self-healing (SS/SH) liner system is based on the fundamental principle that an impermeable seal is self-formed and self-healed by the pozzolanic reaction at the interface between two adjacent reactive layers. The objectives of this study were to evaluate the effect of contaminants on the performance of an SS/SH liner used as a hydraulic barrier, to understand mechanism of volatile organic compound (VOC) sorption on the SS/SH materials, and to estimate the mass transport parameters of contaminants through the SS/SH liner materials.The hydraulic conductivity of the liner material decreased continuously with time, and stabilized at less than 1 10 7 cm/s after approximately 15 days. It is known that the seal at the interface between two reactive layers is self-formed over time, and this contributes to the decrease in the hydraulic conductivity of such a liner system.The retardation of the seven target VOCs tested was greater in the SS/SH liner materials than in a clayey soil specimen owing to the higher sorption capacity. An analytical solution developed to test column equipment could reduce the time required to estimate the hydrodynamic dispersion coefficients of organic compounds by using the data on changes in concentration in the upper reservoir of the column.