  In this work we present a mixed-dimensional mathematical model to obtain the
electric potential and current density in direct current simulations when a
thin liner is included in the modelled domain. The liner is used in landfill
management to prevent leakage of leachate from the waste body into the
underground and is made of a highly-impermeable high-resistivity plastic
material. The electrodes and the liner have diameters and thickness
respectively that are much smaller than their other dimensions, thus their
numerical simulation might be too costly in an equi-dimensional setting. Our
approach is to approximate them as objects of lower dimension and derive the
corresponding equations. The obtained mixed-dimensional model is validated
against laboratory experiments of increasing complexity showing the reliability
of the proposed mathematical model.
