<p>Electrolytic manganese residue (EMR) is posing serious threat to the environment. The seepage of pollutants in the karst area further exacerbated risks to the aquatic environment. In this study, the optimized negative pressure conduction and drainage technology (NPCDT) was applied to treat the leaking EMR depots in karst areas. The concentration of Mn²⁺ and NH⁴⁺ in the downstream groundwater wells significantly reduced from71 to 40%, and from 84 to 39%, respectively, after the treatment by the NPCDT. In the process of NPCDT treatment, the pore water content in the EMR depots was reduced to below the field moisture capacity, and the permeability coefficient decreases and tends to equilibrium, resulting in the downward seepage of the pore water under the action of gravity effectively suppressed. In addition, the engineering project unit cost was about 28% lower than that of the curtain grouting technology. Thus, NPCDT could rapidly, efficiently, and at low cost inhibit the leakage and diffusion of EMR depots pollutant in karst area by regulating the balance of capillary action and gravity. This study provides a novel and efficient engineering technology for the in situ treatment of bulk industrial solid waste caused by the leakage seepage pollution.</p> Graphical Abstract <p></p>