Simultaneous consolidation and remediation of copper contaminated sediments with vacuum electro-osmosis

Contaminated sediment treatment typically requires both dehydration and decontamination, which are normally investigated separately. By integrating vacuum electro-osmosis with electrokinetic remediation technologies, this study demonstrates the potential for simultaneous consolidation and remediation. A novel experiment system for vacuum electro-osmosis was developed to treat sediments with varying initial copper concentrations. The electrical characteristics indicated that both vacuum pressure and copper ions significantly affected the maintenance of electrical conductivity. Vacuum membrane compression increased effective potential by 5–6 V, and there was a clear positive correlation between initial currents and initial concentration of contaminants. The consolidation properties revealed that as contaminants and moisture were removed, the pores between soil particles increased, causing sudden subsidence in the middle area. Higher initial concentration contributed to higher ultimate drainage volumes, peaking at 1950.25 ml, and more evenly distributed settlement. Copper content measurements suggested that excessively low or high initial concentrations of copper diminished remediation effectiveness, with the highest anodic decontamination efficiency at 60%, albeit at the detriment of the cathode region. Copper fractions analysis revealed that weak acid-extractable and water-soluble fractions accounted for over 85% of total copper, predominantly influencing consolidation and remediation.