Detection and Delineation of Contaminant Migration using the Terrain Conductivity Technique outside the Perimeters of the Dompoase Landfill Facility in Kumasi – Ghana.

Abstract

Electromagnetic conductivity survey was conducted outside the perimeters of an active municipal landfill facility located at Dompase, a suburb of Kumasi, Ghana. The study was undertaken to identify potential conductive layers probably connected with leachate communication from the landfill. The Geonics EM 34-3 terrain conductivity equipment was used as the geophysical tool for the survey. Operating in the low induction number regime, three intercoil separations of 10, 20 and 40 m were used in both the horizontal and vertical dipole configurations. The specific area of interest was the two sides of a discharge stream which carries treated effluent from the treatment ponds. Data were acquired at 10 m meter interval along sixteen east–west profiles, each of length 100 m, running approximately perpendicular to the discharge stream. There were seven and nine profiles respectively on the right and left sides of the discharge stream. The high conductivity found within the depths 30 to 60 m close to the southern boundary of the landfill might suggest leachate communication from the landfill. The linear pattern of the contour lines in that anomalous zone probably indicate the presence of zones of weakness trending approximately perpendicular to the direction of flow of the discharge stream. This weak zone could account for the lateral spread of leachate within those depths, where leachate plume has so far migrated.

Keywords: Aquifer, Contamination, Leachate, Electromagnetic conductivity, Geonics EM-34-3, Horizontal dipole, Landfill, Monitoring well, Vertical dipole.