This remediation project was considered one of the more complex and challenging projects in Belgium, due to the complex geology of the soil layers that needed to be addressed, as well as the complexity of the contamination.
The long-lasting activities at the site, which was abandoned in 2013, resulted in complex soil and groundwater contamination with both chlorinated and non-chlorinated compounds including pure product dense non-aqueous phase liquid (DNAPL).
The team selected electrical resistance heating to remediate the source zone. With this technique, the soil is heated to the boiling temperature of water, which volatilizes the contamination. The soil is heated by means of a grid of electrodes that conduct electricity. Electrical resistance heating is mostly implemented in less permeable soil layers when a rapid remediation (usually less than a year) is required.
An additional challenge was the design and installation of an on-site treatment unit capable of handling the high mass load of extracted warm vapors containing several chemical compounds with divergent chemical properties. A complex air treatment unit combining several air treatment techniques was deployed on site for this purpose.
Through our experience with thermal remediation and tendering of lump-sum projects, this project was contracted as a full lump-sum project, independent of total removed mass, which was important for the client. We performed a strict and advanced environmental and health and safety follow-up during the installation and operational phase and kept a close communication line with local authorities.