Soil and Groundwater Remediations

Soil remediation General Biscuits in Herentals (Belgium)

At a biscuit factory, the soil contamination at this area ocurred following a leak in an underground oil tank. The contamination was located partly under and near the office buildings, housing this company’s European headquarters.

Important telephone and data communication cables were located in the dig zone that had to remain continuously in use. Because it proved impossible to relocate these cables, special measures had to be taken to protect these cables.

Because the building had a basement and stood on piles, it was decided to use what is known as slice excavation. This means that the soil was first excavated as far as possible under the safe slope. The last portion directly against the building was then excavated in strips of approx. 2 metres wide and immediately replaced with stabilising sand. This creates a supporting mass that keeps the foundation and intermediate soil in place. In this way, it was possible to excavate right next to the building to a depth of 5 m, without jeopardising the stability and without requiring expensive sheet piling techniques.

The groundwater in excavations was directed over a mobile water purification system before being discharged.

Ultimately, 4,300 tonnes of soil was hauled away to the soil recycling centre in Kallo. After refilling and before refinishing the site, some biosparging filters were installed that can be used to post-treat residual contamination at a later stage. Three of these filters were drilled at an angle under the office.