3D Electrical Resistivity Imaging as a Tool for Quantification of Landfills' Leachate

An alternative to Water Balance Method (WBM) for estimating the quantity of leachate at landfill sites is presented in this paper. The WBM emphasis is on generating rate, while this geophysical approach estimates the in-situ quantity of leachate. The 3D inverted sections were generated using RES2DINV and RES3DINV programs. The resistivity variation in the inverted pseudo-sections clearly delineated the contaminant leachate plume (ρ < 5 Ωm), which facilitated its volume computation. The effective porosity values of clay (0.15) and sand/gravel (0.28) deduced from lithology logs were used in calculating the imaged sections of the leachate. Electrical conductivity values of 1782 µS/cm and 4521 µS/cm were determined for uncontaminated and contaminated zones respectively. A total leachate volume of 2.21 x 102 m3 was estimated beneath the 1600 m2 surveyed area.