These days there is a considerable likelihood of contaminated groundwater, certainly in urban environments. This can result in unwelcome delays in construction works. This was also the case during construction of the foundations for a new hotel in Warsaw. The rapid installation of the correct Desotec mobile activated charcoal filter ensured that the responsible contractor was able to resolve the problem quickly.

The main contractor’s alarm bells suddenly started ringing during construction of the foundation for a new hotel in the Polish capital city. The company had received a permit to pump the groundwater into the sewage system, until local residents began to complain about significant odour nuisance. Investigation showed that the groundwater was severely contaminated with BTEX. The presence of this group of volatile organic compounds (the VOCs benzene, toluene, ethylbenzene and xylene) resulted in both the environmental inspectorate and the fire service visiting to check the construction site.

After the contractor had tried, unsuccessfully, to resolve the problem using separators, one of the partners suggested contacting Desotec, because of this company’s good experiences with Desotec’s mobile activated charcoal filters.

Desotec succeeded in offering a rapid solution: following the initial contact on Monday and approval of the order on Tuesday, the Mobicon 2000 filter was installed and commissioned by Thursday. This reduced the contractor’s forced inactivity on the construction site to just three days; an absolute minimum.

Although the actual pollution level (23 micrograms per litre) proved to be ten times higher than initially thought, the activated charcoal treatment ensured that the problem was soon resolved completely.  As the unpleasant benzine odour also disappeared very quickly and the groundwater quality now satisfied the strict standards, the local authorities quickly gave the green light to restart the activities.

The mobile activated charcoal filter is still in use three months after commissioning, to everyone’s satisfaction. As soon as the contractor has finished the construction of the foundation, Desotec will be on hand with the right approach to handling the saturated activated charcoal. This will be transported to Desotec’s own site for full recycling, so that the raw material can subsequently be used for other applications.

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 legislation, by 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.