UV-O3, UV-H2O2, UV-TIO2 AND THE PHOTO-FENTON REACTION - COMPARISON OFADVANCED OXIDATION PROCESSES FOR WASTE-WATER TREATMENT

Results of the photochemical mineralization of 4-chlorophenol (4-CP) a nd of a wastewater from dyehouse industry by the methods UV/O3, UV/H2O 2, UV/TiO2 and UV/H2O2/Fe2+ (photo-Fenton reaction) are reported and c ompared. Under illumination with a 150 W high pressure mercury lamp, T OC-degradation efficiency for 4-CP had the following order: UV/H2O2/Fe 2+ > UV/O3 > UV/H2O2 = UV/TiO2. Complete decolourization of the dye wa ste occurred within 20 minutes with ozone. A mineralization grade of a pproximately 75% was reached after 90 minutes with the photo-Fenton re action and after 150 minutes with UV/ozone. The combinations UV/TiO2 a nd UV/H2O2 were found to be less efficient for bleaching and degradati on of the dye waste. Furthermore, a novel combination for wastewater t reatment, UV/Fe2+/O3, was investigated. Addition of Fe2+ to the UV/ozo ne process increased the mineralization rate of 4-CP while no signific ant effect on dye waste degradation could be observed.