INTEGRATED GEOPHYSICAL TECHNIQUES APPLIED TO CHARACTERIZE COVERS AND DETECT BIOGAS IN A CONTROLLED LANDFILL

Abstract

Abstract – In the last decades geophysical techniques have been used for detection, characterization and monitoring of landfills due to the high-flexibility and the cost-effectiveness of these methods. The aim of this work is to analyze potential and limits of a new integrated approach, encompassing electrical resistivity tomography, georadar and low-frequency electromagnetic techniques, for the evaluation and the monitoring of biogas accumulation in the subsoil. Experimental geophysical data are acquired in a closed controlled landfill which contains Car-Fluff waste. The electrical resistivity tomography investigation is able to investigate only the shallower layer above the geomembrane, acting as an insulator. On the contrary, georadar and electromagnetic methods can monitor also the waste mass below the geomembrane, where biogas accumulations are likely to occur. Through the joint interpretation of geophysical data we are able to reduce the degree of uncertainty in interpretation of the single geophysical model and to provide a direct correlation between the change in the geophysical parameters and the effective presence of biogas. As a result the non-invasive geophysical techniques can be an important tool for biogas monitoring in controlled landfills and for reducing the associated risks in uncontrolled landfills.