Recovery and environmental recycling of sediments: the experience of CNR-IRET Pisa

Purpose The main results of the experience of CNR-IRET Pisa regarding sediment recovery and recycling are reported. Methods and results In the AGRIPORT project, saline and brackish sediments were mixed with agronomic soil and underwent phytoremediation. After two years, heavy metals and hydrocarbons decreased, and the improvement of chemical and biological properties created a "functional soil" for further applications. Both phytoremediated sediments were refined through landfarming in the CLEANSED and HORTISED projects and applied for civil and agricultural uses. The landfarming process further reduced the organic contaminants in both sediments. Then, in CLEANSED, nursery plants performed similarly in brackish sediment-based substrates as in alluvial soil (control) (33% and 50%). In HORTISED, horticultural plants, grown on substrates with peat and remediated saline sediments (50%), had a yield, number, weight, and fruit quality comparable with those grown on peat. In the "Fondazione Cassa di Risparmio di Pistoia e Pescia" project, the decontaminated saline sediments were successfully co-composted with Posidonia oceanica and reused as nursery growth substrate. Another two European LIFE projects are still in progress. The SUBSED project aims to confirm the suitability of saline-remediated sediments after landfarming as an alternative substrate to peat and coconut fiber for fruit, flowering, and non-food crops. The AGRISED project aims to recover brackish sediments through a co-composting process with green waste to produce an innovative substrate for the cultivation of ornamental plants. Conclusions The projects confer environmental, economic, and social values to sediments, through their eco-sustainable recovery and use in different sectors.