A low-cost method for planar localization of leakage points in closed landfills.

Landfills serve as the primary disposal method for solid waste. However, due to variations in landfill construction and management standards, localized stress concentrations adjacent to the liner may occur, compounded by the heterogeneity of the subsurface structure. This leads to a particularly prominent problem of uncontrolled leachate leakage, posing a severe threat to the surrounding environment and groundwater safety. Geophysical methods are effective for detecting leachate in landfills. However, most of these methods have significant limitations, including signal attenuation by the waste medium, practical challenges related to field operations, uncertainties in data interpretation, and even potential damage to the liner that further elevates leakage risk. To address these limitations, this study develops a novel low-cost direct current (DC) electrical detection method for accurate localization of liner leakage points. Benefiting from the intrinsic properties of DC electrical detection, this method delivers favorable anti-interference performance and is relatively less susceptible to the heterogeneity of landfill waste. We first conduct systematic numerical simulations using COMSOL Multiphysics to quantify how leakage points alter the surface electric field distribution. On this basis, we establish a detection framework that identifies leakage occurrence and locates the defect position by analyzing the spatial characteristics of the electric field. Field experimental results confirm that the proposed method can reliably reflect the spatial distribution of leakage points, and enables fast, minimally invasive, and precise localization of liner defects. This method provides an efficient, low-impact technical alternative for routine landfill liner monitoring and leakage risk management.