Il processo di fitotrattamento dei sedimenti di dragaggio: risultati della sperimentazione AGRIPORT in Italia

In this study, phytoremediation was explored as a sustainable reclamation technology for turning slightly-polluted (heavy metals and hdrocarbons) brackish or saline dredged sediments into a matrix feasible for productive use. To test this possibility, two phytoremediation experimentations were carried out in containers of about 0.7 m3 for brackish sediment and in a basin of 80 m3 for saline sediment. The sediments were pre-conditioned by adding an agronomic soil (30 % v/v) to improve their clayey granulometric composition, and by topping the mixture with high quality compost (4 kg m-2) to favor the initial adaptation of the selected vegetal species. Different plant treatments were compared each other and with an unplanted control sediment (C) in order to evaluate the plant efficiency in remediating and ameliorating the agronomical and functional sediment properties. The healthy state of the plants and the characterization of the sediments after the phytoremediation treatment highlighted the effectiveness of the process in remediating (hydrocarbon reduction of about 50-60% and heavy metal reduction of about 25%) and recovering the sediments from an agronomical (chemical) and functional (biochemical) point of view. The obtained product can be referred to as a ''technosoil'' with most characteristics approaching those of a natural soil. Such technosoil can be feasible for several environmental uses, such as plant growth substrate, geo-material for reforesting eroded land or in the bioremediation of polluted degraded sites.