Like many other longstanding chemical companies, WACKER has some soil contamination on its premises. In the pioneering days of chemical production, nobody was aware of the dangers posed by certain chemicals or that some substances could persist in the ground for extended periods without undergoing degradation.
To remediate this legacy contamination, WACKER has been extracting air from the Burghausen site’s soil since 1989. This predominantly removes highly volatile halogenated hydrocarbons from the soil, which are then incinerated to render them harmless. To date, 1,873 metric tons of chlorinated hydrocarbons (CHCs) have been removed in this way. As soil treatment progresses, the amount of contaminant removed decreases, as is to be expected. In 2008, only 35 tons were removed, despite the continuous increase in the efficiency of the systems involved.
Since 2003, a groundwater stripping plant has been treating an area of localized groundwater contamination east of the Burghausen site. By the end of 2008, 20 tons of CHCs had been removed. Pollutant concentrations have been reduced to one-fifth of their original levels. In order to reduce the discharge of hexachlorobutadiene (HCBD) into the tailrace, we are continuing groundwater treatment at the site’s contaminated areas. The already very low HCBD concentrations are falling further. Currently, 59 kg of the pollutant is being removed per year.
At Portland (Oregon, USA), Siltronic has developed a method of biodegrading trichloroethylene residues in groundwater by means of microorganisms. The site’s environmental protection experts are currently working on scaling-up the process.