W:StS is called to develop a technology that will enable Port and Navigational Authorities (and potentially other Authorities managing fine sediments) to rapidly and economically transform dredged sediment into soil. Currently sediment dredged from Gent-Terneuzen Canal is stored in lagoons at the sediment treatment plant of Envisan (Jan de Nul) for their dewatering at drying fields. This dewatering takes months, with usually one individual lagoon being able to treat just two to three sediment batches per year. Preliminary tests funded by Deltares and executed in collaboration with Jan de Nul and Haedes have demonstrated that a certain species of worms, when added to the sediment in the correct proportion and conditions, have the potential to speed up this process up to a factor 2-3 (in the lab initial dewatering happened 12 times faster, but we foresee that operational considerations should result in a final net effect of 2 to 3 times faster, which remains a big advantage). Such increase in rotation of the lagoons would be a revolutionary event in the field of dredged sediment management and its transformation to soil via dewatering, and ultimately to the entire dredging and sediment disposal industry. Our method is passive and would decrease the use of machinery used for drying of the sediments by putting them in windrows (for the particular engineering application discussed here, but in other sediment disposal operations drains and compaction is used; our technology would also constitute a sustainable alternative here). We also expect to have a positive impact in decreasing methane emissions due to the worms ability to oxidize the sediment rapidly. This project is expected to develop the concept of W:StS, which will constitute an improvement to existing methods to transform sediment into soil. The project results aim to inform the design of a prototype treatment at the Envisan Sediment treatment plant.

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