Optimization of Sediment Washing Technology for Remediation of Heavy Metal Contaminated Sediments

The applicability of sediment washing processes for the remediation of naturally heavy metal contaminated sediments, dredged from Venice lagoon (Italy), is investigated in this work. Experiments were carried out in batch reactors testing either EDTA or HCl as mass separating agents, and referring to the following metals: cadmium, zinc, copper and chromium. To optimize the process, the washing treatment was performed varying: i) the ratio between the amount of the separating agent and the amount of the contaminated sediments; ii) the exposure time. Heavy metal removal efficiencies resulted higher than 50% under most operative conditions, showing the good potentiality of the washing technology for the specific case study.