Jan De Nul Group environmental subsidiary Envisan France has inaugurated the Eco-Materials Production Centre in La Seyne-sur-Mer, the first of its kind in the Mediterranean area.
The centre is part of the SEDIMED research programme, which aims to remove administrative and regulatory barriers and enable sediments to be used in construction works: roads, concrete structures, marine works and eco-modelled landscaping as well as sound barriers. Envisan obtained operating permits for the centre by prefectural decree in November 2013 for a 20-year period.
In Belgium, where dredging major Jan De Nul (JDN) is based, legislation allows for sediments to be upgraded for use in the construction industry. JDN and Envisan have huge experience in building the AMORAS plant for the Port of Antwerp in the SeReAnt joint venture with fellow Belgian dredging giant DEME.
AMORAS opened in 2011 and is still today Europe’s largest treatment plant for maintenance-dredged material. SeReAnt has a contract to exploit the resulting 500,000 tonnes of dry filter cake produced annually until 2026.
Doubtless, lessons learned in building and operating AMORAS will be applied to the new French centre.
Challenges included the innovative character of the integrated recycling, treatment, and storage processes, as well as the requirement to create a long-term and sustainable solution for major volumes of material dredged from the port of Antwerp. Specialised environmental expertise was needed throughout AMORAS’ construction, such as the exploitation of various silt treatment centres, dredging and transport of dredged material; desanding, mechanical dewatering; and storage.
Envisan director Walter De Jonghe commented, “The mission of our new French processing centre is the valorisation of non-submersible sediments originating from dredging operations, as well as polluted soils coming from groundwork sites in the construction and public works sector. We expect it to become the privileged partner of marine contractors, construction and public works agencies, as well as decontamination specialists.
“The centre is built on a 3.4 ha site and is designed to meet all applicable environmental protection standards as well as comply with the strictest traceability requirements,” he continued. “It can receive up to 160,000 m³ of materials per year, has its own water treatment plant and is divided into different zones, each offering a phase in the processing flow.
“The centre offers several sediment and soil treatment techniques, including mechanical dewatering using filter presses, dewatering through active lagooning particle size separation – cycloning, de-sanding, screening – as well as biological treatment and physico-chemical treatment.
“The dredged sediments are brought in by road or marine transport and are directed towards the pre-processing and lagooning zone for dewatering. Dewatered materials are then transported to a waterproof platform in the processing and temporary storage area, where further treatment can be carried out.
“The polluted soils can similarly be brought in by road or maritime transport to the temporary storage area. After screening, they are subjected to either natural treatment processes, such as bioremediation, or more complex treatment methods, such as physical/chemical treatment.
“Materials requiring more specific treatment,” De Jonghe added, “can be grouped, then forwarded to other appropriate processing centres. Treatment residues – plastic, metal, screening debris, green waste, etc – are sorted, grouped and sent to specialised recycling firms or, if none are available, to special waste storage facilities.”