Numerical simulation of copper-contaminated sediment consolidation and remediation through vacuum electro-osmosis

The combination of vacuum electro-osmosis treatment and electrokinetic remediation allows for the simultaneous consolidation and remediation of contaminated sediments, involving multiple coupled fields such as electrical field, hydraulic field, mechanical field, and chemical field. This study couples the charge conservation, vacuum electro-osmosis consolidation, and contaminant transport equations under vacuum electro-osmosis conditions to establish a numerical model for the consolidation and remediation process. Laboratory experiments were conducted for comparative analyses. The numerical results show that the electric field intensity decays from both sides towards the center. However, the other positions align well with the experimental results, indicating the ability of the numerical model to reflect the non-uniform distribution of soil potential. The anode and cathode regions become negative pressure centers, resulting in an increasing seepage velocity towards the negative pressure centers. The numerical results accurately capture the trend of pore water pressure development before 40 h, although the absolute value obtained after 40 h is slightly overestimated. Additionally, the numerical results demonstrate a 47% removal efficiency of copper at the anode after 48 h, which is consistent with the experimental results. The distribution of electric field and contaminants are affected by the shape of the electrode board.