On the CAT site in Vilvoorde, we work with bio-piles, thereby saving about 5,400 truck transports


The closure of the Renault factory in 1997 was a social and economic tragedy for the local community. For decades, the 150-acre site in Vilvoorde was left desolate and unused. Today, Jan De Nul is tackling the pollution of the industrial past on behalf of a project developer. A complex project, for which our environmental works division Envisan developed a sustainable solution. How? By being creative with land, water and air.

With high-tech on-site treatment processes and the reuse of contaminated sites, we provide a circular response to the increasing scarcity of land. And all this with a minimal ecological footprint. At the same time, we are helping to write a new page for the local community, creating space for housing, businesses, recreation and nature.


Creative with land: on-site remediation and sustainable reuse of underutilised land 

The former Renault factory in Vilvoorde is known today as the CAT site. Two large contaminated areas were identified on this site: one linked to a historical household waste dump and one of unknown origin with high concentrations of benzene. Up to a depth of four metres, we excavate 90,000 m³ of contaminated soil, which we store, analyse and remediate as much as possible on site, next to the excavation area. In doing so, we save around 5,400 truck transports, minimise our impact on mobility and reduce our CO2 emissions by 1,195 tonnes.

We remediate the contaminated soil on site using the biological technique of bio-piles, with micro-organisms breaking down the contamination into less harmful forms. The air that is extracted from the bio-piles is collected and purified through a filter, combined with a catalytic afterburner. The heat released in this process is recovered to raise the temperature in the bio-piles. Clearly a solution based on maximum circularity. 

Creative with water: 4 circular solutions for reusing water

Water is a natural resource that Jan De Nul wants to safeguard for future generations. When executing environmental projects, we avoid using tap water by providing circular alternatives. This requires a unique approach, tailored to the specific project requirements.    

  • On the CAT site in Vilvoorde, we deploy a temporary mobile water treatment plant to purify contaminated drainage water. 
  • On the asbestos-contaminated Modernite site in Hofstade, automatically controlled atomisation systems prevent the dispersion of asbestos fibres on and next to the site. The atomisation systems are fed with water from the Dender.
  • During the groundwater remediation on the VOPAK site (storage and transhipment of chemical and petrochemical products in the port of Antwerp), we reuse the purified process water to wash the air contaminated with volatile organic compounds.
  • In Gijzegem near Aalst, we remediate groundwater contaminated with chlorinated solvents for a textile company. The purified waste water is reused by the customer as process water in its production plant.


Creative with air: clean air and a strong CO2 reduction

The remediation activities of Jan De Nul make contaminated land liveable again. Not only land and water, but also air is essential for this. We do this by controlling and monitoring our emissions to the maximum extent possible. Our on-site biological remediation operations drastically reduce our CO2 emissions. On the CAT site, we save an additional 13 tonnes of CO2 by using 100% green energy of local origin. We also deliberately use an electric atomiser instead of a diesel-powered device. 

With its on-site remediation activities, Jan De Nul meets the high-tech requirements set by customers for complex projects. By simultaneously reducing our ecological footprint, we can even exceed our customers' expectations. Our environment division Envisan aims to expand this successful approach, both on a national and international scale. In Wallonia, we have now put our first mobile physicochemical washing plant into operation. A quick solution for the remediation of heavily contaminated sites, such as soils contaminated with PFOS. A promising evolution for the future.

This article is an extract from the activity report 2021.