Validation of a mixed-dimensional code for the analysis of highly resistive liners in landfills

Municipal solid waste landfill (MSWLFs) monitoring requires advanced techniques for assessing the condition of the liner underneath the waste mass, as holes or damages can cause leachate leakage into the subsurface. Electrical resistivity tomography (ERT) can be employed to address this kind of problem and discriminate between the low conductivity of the high-density polyethylene (HDPE) membrane and the high conductivity of the leachate. In this research, we present a simple test in which we evaluate a Python code based on a mixed-dimensional mathematical model that we developed for the solution of the forward problem. The reliability of the new code is tested against measurements performed in the laboratory, the analytical solution for a two-layer model (roughly corresponding to the waste and the liner), and the results obtained with pyGIMLy, a Python open-source library for multi-method modelling and inversion in geophysics. The modelling tests have been performed considering 3D meshes as similar as possible for both software, though some differences remain because of different approaches used in mesh generation as well as in numerically solving the geoelectrical problem.