Oxidative treatment is one of the options to eliminate emerging pollutants (EPs) from drinking water or wastewater. For drinking water treatment, the ozonation technology is already implemented at many sites all around the world, so far mostly for disinfection purposes. However, in some countries such as the Netherlands surface water contains relatively high bromide concentrations, which leads upon reaction with ozone to the formation of bromate, a suspe cted carcinogen. In such a case, UV/H2O2 treatment is considered a useful alternative, despite the fact that energy requirements are substantially higher compared to treatment with ozone or O3 /H2O2. Only in recent years, the oxidative treatment of wastewat er has been investigated to not only protect our water resources, but also the ecosystem from pollution with chemicals used in our daily life. In Switzerland, the first permanent full scale plant with ozonat ion, WWTP Neugut in Dübendorf, is running since March 2014 . Its performance was investigated i n detail in the DEMEAU project. The goal of this paper is to present a decision basis for the implementation of oxidation technologies to eliminate EPs. Depending on the composition of the water in different European regions, one or the other treatment is recommended. The different parameters that influence the efficiency of oxidation and the formation of by - products are discussed. A decision tool is presented to decide if oxidative treatment of wastewater is rec ommended and under which circumstances the treatment of drinking water with ozone, O3/H2O2 , or UV/H2O2 may be the treatment of choice.