Abstract:The conventional water treatment technologies, mostly relying on physical and biological processes, seem to be inadequate for effective removal of priority substances such as pesticides, while advanced oxidation processes showed a good performance for the same purpose. The aim of the study was to evaluate UV-C/H 2 O 2 and UV-C/S 2 O 8 2-processes for treating seven pesticides listed as priority substances (PS-Ps) within the EU Water Framework directive; alachlor, atrazine, chlorfenvinphos, cybutryne, diuron, isoproturon and simazine. The influence of pH and pollutant/oxidant ratio ([PS-P]:[OX]) on the degradation kinetics was evaluated using full factorial plan and response surface modeling. The degradation of PS-Ps by both photooxidation processes obeyed first-order kinetics. Degradation kinetics of PS-Ps is highly depended on [PS-P]: [OX], while pH has minor significance, particularly in UV-C /S 2 O 8 2-process. In most cases degradation kinetics by UV-C /S 2 O 8 2-was several times faster in comparison to UV-C /H 2 O 2 process. In addition, the inhibitory influence of NOM on the degradation of PSs in the mixture was determined.