Optimization of electrokinetic treatment conditions for a metal-contaminated dredged sediment

The suitability of EK remediation to remove hazardous metals from dredged marine sediments is currently being investigated in the Life+ SEKRET project (“Sediment ElectroKinetic REmediation Technology for heavy metal pollution removal”). A preliminary sediment characterization campaign was conducted during the initial stages of the project in the study area, namely the Livorno harbor site (located in western central Italy), where the harbor authority has to deal with ~100,000 m3 of dredged sediments per year. Considering the threshold concentrations established by the Italian regulation for soil in residential areas, the critical contaminants were found to include Cu, Cd and Zn; Cr was present in sediment at concentrations slightly below the limit value. Adopting the informal criteria defined by the Italian Ministry for the Environment, Ni should also be included among the contaminants of concerns. The grain size distribution of sediment was as follows: 18.1% coarse sand, 35.2% fine sand, 46.7% fine fraction (silt + clay), confirming the potential suitability of the material for the EK treatment.