New process already cleans groundwater in the ground

How iron oxide can clean contaminated groundwater

Industrial areas are often contaminated with heavy metals that also enter the groundwater. The cleaning of such floors is extremely labor-intensive and cost-intensive. Until now, there were no economically reasonable remediation methods to remove dissolved heavy metals sustainably from the groundwater again. In a major EU project, a simple procedure has now been introduced that eliminates pollutants directly in the soil. The new method has already been successfully tested in three contaminated areas.

The project was coordinated by the University of Duisburg-Essen (UDE). The central role of the new process involves special iron oxide nanoparticles that are injected into groundwater-bearing rocks. There, the particles form a barrier that filters contaminants such as arsenic, chromium, copper, lead and zinc out of the water.

At industrial sites, the soil and groundwater are often contaminated with heavy metals. A new process is intended to extract these metals from the groundwater already in the soil. (Image: Ralf Geithe / fotolia.com)

How does the new procedure work??

"We have made colloidal iron oxide nanoparticles," explains chemist Dr. med. Beate Krok in a press release on the new groundwater remediation. These particles have unique properties. When placed in a water-bearing rock layer, they cover the surface of the sediment to form an adsorption barrier. According to Krok, heavy metals in the water that flow through such a barrier attach themselves to this barrier and are thus retained permanently.

The advantages over other methods

So far, tedious and expensive procedures with structural measures were required to clean such contamination. The groundwater had to be pumped to the surface and cleaned over a long period of time. By contrast, the new method can also be used in difficult terrain and without structural measures. According to the UDE, the operational readiness is already given after a few days. In addition, the method is not only suitable for decommissioned, but also for active industrial sites.

Successfully tested

The EU project team has already been able to successfully use the process on three heavily polluted areas in Portugal, Spain and also in Germany in the Cologne area. Tests showed that the heavy metals in the groundwater could be reduced. The project was documented in the documentary "The ReGround Project", which will be premiered on January 29 at the University of Duisburg-Essen. (Vb)