Life cycle assessment of remediation alternatives for dredged sediments

The Life Cycle Assessment (LCA) is an ISO standardized and widely used methodology for environmental assessment of products, processes and services, by identifying, quantifying and evaluating all the resources consumed and all the emissions and wastes released. The LCA methodology enables adequate comparison between different remediation options and can be used as a decision-making tool for the authorities. In this study, LCA was used to compare, in terms of their associated environmental burdens, two scenarios for managing the contaminated dredged sediments of the seabed of the Livorno Port area. The compared options were: (i) confined longshore disposal, i.e. placement of dredged material in a confined disposal facility; (ii) phytoremediation treatment, by an association of salt-tolerant shrub and grass species, aimed at turning the polluted sediment an agronomic substrate (techno-soil). The results of the life cycle impact assessment underline that the potential impacts of the two compared options involve different environmental problems. Indeed, for phytoremediation the most significant impacts are related to energy and resources consumption, while for the confined disposal are related to loads in the marine ecotoxicity categories. Therefore, phytoremediation can be considered a promising alternative solution for the management and valorization of contaminated dredged sediments.