Removing AOX from groundwater at Paris Metro construction site

In 2013, the Parisian authorities launched the Grand Paris Express programme to build 200 km of extended Metro lines plus 68 new stations.

This involves extensive groundworks, some of which are at sites where former industrial or commercial activity has left the land and groundwater in need of remediation.

Chlorinated compounds from pharmaceutical, chemical, and cleaning products, measured as AOX, pose a particular risk to human health and aquatic life.

A major French remediation and sanitation specialist was commissioned to purify all groundwater before discharging it into the Seine. This company has worked regularly with DESOTEC on previous remediation projects, so knew it could rely on our help with this mammoth, high-profile task.

It contacted us with a view to treating pumped-up groundwater at the Pont de Sèvres in the heart of the city, alongside the busy D1 motorway.

The filters operated at full power for several months, successfully reducing AOX and other substances in groundwater to the required level. The groundwater was then safe for discharge to the Seine.

As this is a phased project, DESOTEC is likely to be called upon to supply further filters if more AOX or other compounds are discovered in the groundwater at later stages.

Mobile activated carbon filters are an excellent solution for temporary remediation projects. They are plug-and-play, making them simple to operate. They have a small footprint, so fit into crowded construction sites. We supply them on a rental basis, so they require no upfront investment from the customer.

Our full-service solution also includes safe and sustainable filtration waste handling. We remove all spent carbon in closed filter units away from customers’ sites, and take it to our facilities for analysis.

All adsorbed molecules are destroyed in DESOTEC’s furnaces, which are under continuous online monitoring to ensure that only harmless water vapour exits the chimney. Wherever possible, carbon is reactivated for reuse, keeping costs low and boosting sustainability.