The groundwater underneath the community of Bad Fischau-Brunn cannot be used for drinking water because it is polluted with perchloroetylene (PCE). At present the PCE concentration has a level of 60-80 mg/l, while the limit value for drinking water in Austria is 10 mg/l. Without treatment, therefore, this water cannot be used as drinking water. Current state-of-the-art technology is filtration with activated carbon. However this merely leads to a transfer of pollution from water to coal. Applying this process also results in CO2 emissions. Moreover, there is always a risk of dioxin being produced in such a process. The present proposal is based on a combination of ozone and electron beam irradiation to produce OH-free radicals and to use them to clean the water.