N.V. PWN Water Supply Company North Holland is constructing the Heemskerk treatment plant. As a barrier against more than 300 pesticides PWN is considering the application of advanced oxidation processes. Peroxone treatment can realize the goal for pesticide degradation. However formation of bromate cannot be avoided completely, especially at low water temperature. Under optimal conditions for pesticide degradation and restriction of bromate formation inactivation of clostridia spores is very limited. UV/H2O2-treatment can realize the same goal for pesticide degradation without any bromate formation. Under optimal conditions for pesticide degradation inactivation of clostridia spores is complete. For bromide-rich waters UV/H2O2-treatment is a very promising technique for pesticide control and inactivation of micro-organisms. PWN will pursue application at their Heemskerk treatment plant for organic contaminant control and, in a later phase, at their Andijk treatment plant for both organic contaminant control and disinfection.