Activated carbon takes care of contaminated groundwater

Desotec Mobicon - groundwater filtration

A city that receives the Olympic Games is the epicentre of the world for two weeks. Paris, which will host the global sporting event in 2024, leaves nothing to chance to make a great impression. The French, for example, are working on extending and modernising the Metro network. Desotec contributes to this by providing sixteen activated carbon filters for a remediation project related to these Metro works. 

Although it will take another five years before Paris hosts the Olympic Games, many infrastructure works are already taking place in the city. Grand Paris Express is the name of the major Metro project that is currently in progress in the French capital. The works aim to build no less than two hundred extra kilometres of Metro lines and 68 new Metro stations. This will also involve numerous of groundworks, including the pumping up and decontamination of polluted groundwater. For this gigantic task, a major French specialist in remediation and sanitation was commissioned to thoroughly purify all groundwater and then discharge it into the Seine.

This specialist has already worked regularly with Desotec on previous remediation projects and is also counting on our services for Grand Paris Express. Some time ago, for example, we supplied five Mobicon filters. For the next phase of the remediation project, Desotec was asked to install 16 new Mobicon filters by the end of May 2019. It concerns eight sand filters that – after the water has first undergone decantation – will remove all suspended substances. A further eight activated carbon filters will then be needed to filter all AOX (Adsorbable Organic Halides) substances from the water. A large number of filters is necessary to cope with the high flow rate (800 m³/h).  Activated carbon is extremely suitable for the elimination of low AOX concentrations from contaminated water streams. 

The sixteen Mobicon filters will operate at full power for three to five months at the Pont de Sèvres, at a location in the heart of the city, located along the busy D1 motorway. The timely delivery and installation of so many filters within a limited timeframe is a considerable challenge, but one that is fully in line with Desotec’s mission to quickly anticipate urgent questions through flexible solutions. The customer opted for mobile activated carbon filters because they are an excellent solution for temporary projects and because they can operate on a limited surface area. 

As this is a phased project, it is likely that the customer will also rely on Desotec’s solutions and services for the next step of the works for Grand Paris Express.


At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislationby an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.