Smooth progress in remediation works at confluence of Grote Laak

On 14 July 2025, remediation works have restarted in the confluence area of the Grote Laak. These works mark the start of one trajectory of the remediation project of the Grote Laak. The remediation works are crucial to eliminate the risks posed by the pollution in this waterway and to restore its ecological value. The works in this confluence area consist of the conventional remediation of the Grote Laak and its banks, as well as the nature-based remediation of the two flooding areas Zammelsbroek and Trichelbroek. Thanks to the relatively dry weather and favorable terrain conditions, we are well ahead and on schedule.

As a first step the site has been cleared and a downstream sediment trap has been installed, to catch suspended matter during the works. A temporary basin has been installed for contaminated sludge to drain, before it is transported to the final storage site of Tessenderlo Group (Kepkensberg). Once the works are completed, we will dismantle this basin and restore the site to its original condition.  The first segment of this trajectory of the Grote Laak and its tributaries have been remediated, both the sediment and the banks. Contaminated sediment and soil have been removed and replaced by clean soil.  

The floodplains Trichelbroek and Zammelsbroek will be remediated using a nature-based and in-situ method. Several measures are being taken to keep contamination permanently below the water table, so that the metals will stabilize due to complexation with sulfides. Most of the measures in Trichelbroek are executed. Local elevations were excavated, an earthen dam has been constructed to enclose pollution, an adjustable inlet and outlet for surface water towards the wetland have been installed and one of the three fish-passable weirs is in progress.

From January 2026 onwards we will complete the remediation of sediment and banks of the waterway in the 2^nd segment until the confluence in the Grote Nete. For the nature-based remediation we will complete the installation of the three weirs and place an inlet structure for Zammelsbroek.

We expect to complete the works by early summer 2026.