Abstract: The results of an experimental study of the oxidation of industrial 5% water runoff of the propylene epoxidation process carried out under supercritical fluid conditions (T = 673-873 K, P = 25 MPa) on a continuous plant using oxygen as the oxidant are presented. The Chemical Oxygen Demand (COD), pH and mass spectra of the initial sample and reaction products were determined. The regularities of the efficiency of water runoff oxidation on the temperature and duration of the reaction are established. The elemental composition of the solid sediment is determined.