• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.64-72
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• 1996

The effect of $O_3$, $O_3/pH$, and $O_3/H_2O_2$, $O_3/UV$, and $H_2O_2/UV$ advanced oxidation process(AOP) were investigated for the treatment of tetrachloroethylen(PCE) at various condition. The removal efficiency of 10, 20, and 30ppm PCE by ozonation were almost same, only about 60%. And pseudo first-order rate constants, ko for overall oxidation was about 0.097($min^{-1}$). In the $O_3/pH$ AOP experiment for the 20ppm PCE, the removal rate of PCE increased with the increase of pH. However, mineralization rate of PCE at pH 7 was higher than at pH 10. In the $O_3/H_2O_2$ AOP, the removal rate of PCE was the highest at peroxide-to-ozone dosage ratio of about 0.9, which PCE was removed over 99.95%. Despite 42% of PCE was directly photolyzed by the UV irradiation, the removal efficiency of PCE by $O_3/UV$ AOP was only about 70%. In $H_2O_2/UV$ AOP, the removal efficiency of PCE increased to about 98% in proportion to the $H_2O_2$ injection concentration at constant UV intensity of 5W/l.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.267-273
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• 2005

Dye wastewater generally contains strong color and non-biodegradable materials. Therefore, the conventional wastewater treatment plant can hardly meet the regulation of wastewater effluent water. In this study, a pilot plant of the conventional process followed by advanced oxidation process (AOP), was set up to treat the dying wastewater. The treatment efficiencies on the various candidate processes, such as ozone alone, UV alone, ozone/UV, $ozone/H_2O_2$, $H_2O_2/UV$ and $ozone/UV/H_2O_2$, were investigated in the various ozone and $H_2O_2$ doses. As the results, the $ozone/H_2O_2$ process, among the tested processes, showed the highest efficiency for removing color and $COD_{Cr}$. For color removal, the ozone alone process was enough without combining UV or $H_2O_2$. No significantly enhanced efficiency for removing color and $COD_{Cr}$ by UV irradiation was observed because of the very low transmittance of UV light in dye wastewater.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.319-323
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• 2007

The Advanced Oxidation Process (AOP) is being increasingly used to oxidize complex organic constituents in treated effluents from domestic wastewater treatment plants. Generally, ${NO_3}^--N$ concentrations ranges between 5 and 8 mg/L for biologically well-treated effluents. However, nitrate ions, ${NO_3}^-$, affects on oxidation as not only a well-known strong absorber of UV light below 250 nm of wavelength but also as an OH radical scavenger. The objective of this study was to evaluate the AOP systems for degradation of 2,4-DCP, and to delineate the effect of nitrate ions on UV oxidation of 2,4-DCP by conducting a bench-scale operation at various reaction times and initial concentrations of $H_2O_2$. The experimental results indicated that 2,4-DCP could be completely oxidized by $UV/H_2O_2$ process with an initial $H_2O_2$ concentration of 20 mg/L at a retention time of 1.0 min or longer. Nitrate ions did not show any adverse effect on 2,4-DCP oxidation at this high $H_2O_2$ concentration, and the practical initial $H_2O_2$ concentration and reaction time for the 80% oxidation turned out to be 5 mg/L and 1.0 min, respectively.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.690-695
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• 2018

Advanced oxidation processes (AOPs) composed of O3 and UV were applied to degrade penicillin (PEN). The degradation efficiency was evaluated in terms of changes in the absorbance (ABS) and total organic carbon (TOC). The combination of $O_3/H_2O_2/UV$ and $O_3/UV$ showed the best performance for the reduction of ABS (100% for 9 min) and TOC (70% for 60 min) values, although the mineralization was uncompleted under the experimental condition in this study. The change in biotoxicy was monitored with Escherichia coli susceptibility and Vibrio fischeri biofluorescence. The E. coli susceptibility was eliminated completely for 9 min by $O_3/UV$, and the toxicity to V. fischeri biofluorescence was 57% reduced by $O_3/H_2O_2/UV$. For the ultimate treatment of PEN, it is suggested that an AOP using $O_3/UV$ is followed by biological treatment, utilizing the enhanced biodegradability by the AOP. During 30 min of $O_3/UV$ treatment, the $BOD_5/COD$ ratio as an indication of biodegradability showed about 4-fold increment, compared to that of using a non-treated sample. TOC removal rate for AOP-pretreated PEN wastewater increased 55% compared to that of using the non-pretreated one through an aerobic biological treatment by Pseudomonas putida for artificial wastewater containing 20 mg/L of PEN. In conclusion, $O_3/UV$ process is recommended as a pretreatment step prior to an aerobic biological process to improve the ultimate degradation of penicillin.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.643-650
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• 2005

In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.298-303
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• 2007

Several combinations of ozone based advanced oxidation processes were tested for the treatment of red water (RW) containing recalcitrant chemical pollutants produced from 2,4,6-trinitrotoluene (TNT) manufacturing process. $O_3$, $UV/O_3$, $UV/O_3/H_2O_2$, $UV/O_3/H_2O_2/Fe^{2+}$ processes were tested for the treatment of RW. The order of organic and color removal efficiency was found to be : $O_3{\leq}UV/O_3$ < $UV/O_3/H_2O_2$ < $UV/O_3/H_2O_2/Fe^{2+}$. The optimum conditions for the removal of organic and color in the $UV/O_3/H_2O_2/Fe^{2+}$ process were 0.053 g/min of ozone flow rate, 10 mM of $H_2O_2$ concentration and 0.1 mM of $FeSO_4$ concentration. Organic and color removal efficiencies were 96 and 100 % respectively in the $UV/O_3/H_2O_2/Fe^{2+}$ process. tert-butyl alcohol (t-buOH) was used as the hydroxyl radical scavenger. Enhancement of hydroxyl radical production was achieved by the combination of ozone with several oxidants such as UV, $H_2O_2$, $Fe^{2+}$.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.663-670
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• 2007

This study was performed to provide basic information for evaluating the efficiency and applicable extent of photocatalysis and ozonation for the treatment of dye wastewater. The treatability of dye wastewater by $UV/TiO_2$ and $UV/TiO_2/O_3$ advanced oxidation process (AOP) was investigated under various conditions. The experiments were conducted in a batch reactor of 50 liters equipped with twelve UV Lamps of 16W. In $UV/TiO_2$ AOP, the removal efficiency of TCODMn and Color increased to 58% and 67% respectively with increasing UV intensity. Also, The removal efficiency of TCODMn and Color increased to 97% and 99% respectively with increasing $H_2O_2$. Acid area was more efficient than neutral and alkalic areas in wastewater treatment, and pH 5 was the most effective and the treatment efficiency continually increased as the amount of photocatalyst was increased. When the photocatalyst was increased, TCODMn was removed faster than Color.

• Textile Coloration and Finishing
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• v.23 no.4
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• pp.274-283
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• 2011

Effect of pH on ozone oxidation and peroxone AOP(Advanced Oxidation Process) process was analyzed and the optimal efficiency for both processes was obtained at pH 7.5. In case of ozone oxidation process, the efficiencies of color, $COD_{Mn}$ and $BOD_5$ removal were measured to 93%, 70% and 89% at a reaction time of 50 min(ozone dosage of 111.67mg/$\ell$). When reaction time increased to 90 min(ozone dosage of 201mg/$\ell$), the efficiencies of color, $COD_{Mn}$ and $BOD_5$ removal were increased by 3~5 %, indicating that the increment of removal efficiency was insignificant considering longer reaction time. Similarly, the ozone/$H_2O_2$ ratio was optimized to 0.5 for peroxone AOP process. Removal efficiencies of color, $COD_{Mn}$ and $BOD_5$ were measured 95%, 81% and 94% at a reaction time of 50 min(ozone dosage of 111.67mg/$\ell$). When reaction time increased to 90min(ozone dosage of 201mg/$\ell$), the removal efficiency of color, CODMn, and BOD5 increased slightly by 1~5%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.645-654
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• 1994

Photocatalytic oxidation conditions of reactant recirculation flow rate 275 mL/min, aeration rate 2 LPM and $UV+TiO_2+H_2O_2$(500 mg/L) proved to be appropriate for water including organic materials treatment. With increasing turbidity and suspended solids concentration, at turbidity 10 NTU-suspended solids concentration 29 mg/L the phenol degradation efficiency increased, which in turn decreased at turbidity 50 NTU-suspended solids concentration 170 mg/L, however no significant differences were observed, demonstrating similar results with those obtained at zero turbidity and suspended solids concentration. The degradation efficiency of phenol decreased with increasing influent phenol concentrations. The $UV+TiO_2+H_2O_2$ photocatalytic advanced oxidation process conducted is considered to be possibly applied to the drinking water treatment, and the post-treatment process of biological wastewater treatment.

• Journal of Korean Society of Water and Wastewater
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• v.17 no.4
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• pp.542-549
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• 2003

In the present study, the feasibility of $UV/H_2O_2$ systems was investigated using low and medium-pressure lamps on biologically treated wastewater effluents for secondary effluent reclamation. Two types of UV lamps were used as the light sources (a 39-W low-pressure mercury lamp and a 350-W medium-pressure mercury lamp). The results from these UV systems showed that the removal of organic compounds could be achieved in the contact time of longer than 30min (i.e., low UV doses). Efficiencies of color removal and disinfection were far better than those of organic matters measured as TOC, DOC and $TCOD_{cr}$. In the low-pressure lamp UV system, it has been found that DOC and color removals were 60.9 and 86.2% with 50mg/L of $H_2O_2$ and contact times of 30 minute, respectively. Whereas, with the medium-pressure lamp UV system, TOC, DOC and color removal were 27.1, 5.6 and 95% with 14.3mg/L of $H_2O_2$ and 14 minute of contact times, respectively. Both systems could be applied for the reclamation of secondary effluent treated with biological treatment processes.