A life cycle assessment study on the stabilization/solidification treatment processes for contaminated marine sediments

Contaminated marine sediment management strategies involves in situ and ex situ options for preventing pollutants from re-entering the water column, thus becoming available to benthic organisms and subsequently entering aquatic food chains. These pollution abatement strategies can cause significant secondary environmental impacts which in some cases have been considered to be even higher than the primary ones. This study aims at identifying and quantifying through life cycle assessment (LCA) the environmental impacts of the application of Stabilization/Solidification (S/S) options for the remediation of contaminated marine sediments from the Mar Piccolo in Taranto (Southern Italy). The analysis considers all the stages involved in marine sediments processing (dredging, transport, storage, treatment, safe disposal of the treated sediments) but focuses on several S/S options (4 S/S mixes with cement and 4 mixes with lime). These S/S options were tested at lab scale with different results in immobilizing heavy metals and organic pollutants. The LCA suggests that the ex-situ treatment could contribute to improving the current situation and that the marine sediments S/S operation generates a complex environmental profile which is dominated by the treatment phase, which in turn shows that optimization of this stage could lower these impacts.