This study investigated the treatment of acetaminophen in municipal wastewater by conventional ozonation, ozone-based advanced oxidation, ozone/UV, and the electro-peroxone process. The ozone/UV process and electro-peroxone process of electric power consumption increased 1.25 and 2.04 times, respectively, compared to the ozone process. The pseudo-steady OH radical concentration was the greatest in the　electro-peroxone process and lowest in the ozone process. The specific energy consumption for TOC decomposition of the ozone/UV process and electro-peroxone process were 22.8% and 15.5% of the ozone process, respectively. Results suggest that it is advantageous in terms of degradation performance and energy consumption to use a combination of processes in municipal wastewater treatment, rather than an ozone process alone. In combination with the ozone process, the electrolysis process was found to be more advantageous than the UV process.

Diethyl phthalate (DEP) and nonylphenol (NP) are widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including TiO2, as advanced oxidation processes (AOPs) were applied to a DEP and NP contaminated solution. When only the application of US, the optimum frequency for significant DEP degradation and a high rate of hydrogen peroxide (H2O2) formation was 283 kHz. We know that the main mechanism of DEP degradation is radical reaction and, NP can be affected by both of radical reaction and pyrolysis through only US (sonolysis) process and combined US+UVC (sonophotolysis) process. At combined AOPs (sonophotolysis/sonophotocatalysis) such as US+UVC and US+UVC+TiO2, significant degradation of DEP and NP were observed. Enhancement effect of sonophotolysis and sonophotocatalysis system of DEP and NP were 1.68/1.38 and 0.99/1.17, respectively. From these results, combined sonophotocatalytic process could be more efficient system to obtain a significant DEP and NP degradation.

Advanced oxidation processes involving O3/H2O2 and O3/catalyst were used to compare the degradability and the effect of pH on the oxidation of 1,4-dioxane. Oxidation processes were carried out in a bubble column reactor under different pH. Initial hydrogen peroxide concentration was 3.52 mM in O3/H2O2 process and 115 g/L (0.65 wt.%) of activated carbon impregnated with palladium was packed in O3/catalyst column. 1,4-dioxane concentration was reduced steadily with reaction time in O3/H2O2 oxidation process, however, in case of O3/catalyst process, about 50～75% of 1,4-dioxane was degraded only in 5 minutes after reaction. Overall reaction efficiency of O3/catalyst was also higher than that of O3/H2O2 process. TOC and CODCr were analyzed in order to examine the oxidation characteristics with O3/H2O2 and O3/catalyst process. The results of CODCr removal efficiency and ΔTOC/ΔThOC ratio in O3/catalyst process gave that this process could more proceed the oxidation reaction than O3/H2O2 oxidation process. Therefore, it was considered that O3/catalyst advanced oxidation process could be used as a effective oxidation process for removing non-degradable toxic organic materials.

The degradation of Rhodamine B (RhB) in water was investigated in laboratory-scale experiments, using five advanced oxidation processes (AOPs): UV/H2O2, fenton, photo-fenton, UV/TiO2, UV/TiO2/H2O2. The photodegradation experiments were carried out in a fluidized bed photoreactor equipped with an immersed 32 W UV-C lamp as light source. Initial decolorization rate and COD removal efficiency were evaluated and compared. The results obtained showed that the initial decolorization rate constant was quite different for each oxidation process. The relative order of decolorization was: photo-fenton > UV/TiO2/H2O2 > fenton > UV/H2O2 > UV/TiO2 > UV > H2O2. The relative order of COD removal was different from decolorization: photo-fenton ≒ UV/TiO2/H2O2 > UV/TiO2 > fenton > UV/H2O2. The photo-fenton and UV/TiO2/H2O2 processes seem to be appropriate for decolorization and COD removal of dye wastewater.