ADVANCED OXIDATION PROCESSES AGAINST PHENOLIC-COMPOUNDS LIT WASTE-WATER TREATMENT

Experimental research into the oxidative treatment of aqueous solution s and wastewaters containing phenolic compounds was undertaken. Ozone, supported by short wavelength UV-irradiation, hydrogen peroxide and t itanium dioxide catalyst, was selected as an oxidant in the following combinations: O.3, O-3/H2O2, O-3/UV, O-3/TiO2, O-3/UV/H2O2 and O-3/UV/ TiO2. 5-Methylresorcinol was chosen as a model compound for the experi ments with synthetic phenolic solutions. The results obtained from the se experiments were compared with the results of oxidative purificatio n of wastewaters produced from the thermal treatment of oil shale in E stonia. The ''ozone - hydrogen peroxide'' combination showed a higher efficiency for the destruction of phenolic compounds compared with non -accompanied ozonation. The specific ozone consumption also was reduce d 1.2-1.3 times in combination with hydrogen peroxide. Short wave UV-r adiation and titanium dioxide showed no influence on the specific ozon e consumption, due to the high optical density of phenolic compounds i n the short UV-wavelength range. The wastewater biodegradability, desc ribed as BOD5/COD ratio, increased only slightly subsequent to ozonati on. In contrast, a significant decrease in biodegradability with incre asing oxidant dose was observed when an O-3/H2O2 combination was used.