Comparison of different approaches to treatment of residues resulting from contaminated sediments dredging.

Nowadays, the management of the residues represented by dredged contaminated sediments is a complex problem. For a sustainable approach to the problem, considering sediments as a resource is advisable, therefore developing technologies for their effective treatment is essential. In Italy more than 50 areas have been defined remediation sites of national interest; most of these sites are marine coastal waters characterized by significant sediment contamination caused, in particular, by persistent, bioaccumulative and toxic substances like PAH, PCB, mercury, cadmium and other heavy metals. In this study, three different approaches were adopted for treating sediments dredged from an industrial harbour located in South-West Sardinia (Italy): a) chemical washing using 0.1-0.2 EDTA M extracting solutions, b) enhanced electrokinetics using 0.2 EDTA M solution as circulating solution, c) mechanical washing, consisting of wet sieving, separation through hydrocyclone and gravimetric separation by means of vibrating tables. The best results were achieved by applying chemical and mechanical washing.