Sediment and Sludge Treatment

Soft Soil Improvement® (SSI)

As part of the creation of an industrial zone in Vilvoorde, the Ministry of the Environment and Infrastructure was confronted with a severely contaminated section of the river "Zenne". Because the sediment exhibited very high concentrations of heavy metals (arsenic, lead and mercury), remediation of the site was required.

In order to immobilise and stabilise the contaminated sediment in situ, we combine this with chemical additives and stabilisers, a technique called Soft Soil Improvement®. It is a patented, highly advanced technology we developed ourselves, that consists of a combination of stirring up sediment under very high pressure and mixing it with chemical additives at a great depth. DEC succeeded with this method of stabilising and immobilising all 30,000 m³ of sediment in only six months.

The benefits of this technology are briefly listed below:

• Because this is an in situ technique, almost none of the contaminated material had to be brought to other locations, in contrast to the traditional method of excavated contaminated sand or soil and then refilling. This means benefits in terms of time and resources.
• Given that the sediments are immobilised and stabilised on site, an additional waste site for the excavated sediment is not required.
• Soft Soil Improvement® guarantees good results in the long term.
• To achieve a different immobilisation effect, one can simply mix the additives in a different proportion to adapt the column configuration. In contrast to the traditional systems, this means high flexibility.
• Soft Soil Improvement® is an advanced technology with mobile equipment and a simple control system. This makes the technique economical even for small projects.