• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.805-813
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• 2013

In this study, molecular size distribution of natural organic matter (NOM) after ozonation was measured and its effect on adsorption capacity of activated carbon was investigated. According to the results, the molecular size of NOM was limitedly changed. Specifically, the molecular size of NOM between 5,000 to 10,000 Da were slightly decreased with increasing ozone doses. The adsorption capacity after ozonation was evaluated using Freundlich isotherm with ideal adsorbed solution theory (IAST) which simulated the multi components adsorption. Further, mini-column test was conducted. The Freundlich constant, K was reduced after ozonation and the non-adsorbable fraction was increased with ozonation. However, no correlation between K and ozone doses was found. The present study also agreed with the correlation between adsorption capacity and pore size characteristics of activated carbon.

• Journal of Environmental Science International
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• v.32 no.3
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• pp.197-204
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• 2023

This study aims to inactivate Artemia sp. (Zooplankton) in ballast water through the dielectric barrier discharge (DBD) plasma process. The DBD plasma process has the advantage of enabling direct electric discharge in water and utilizing chemically active species generated by the plasma reaction. The experimental conditions for plasma reaction are as follows; high voltage of 9-22 kV, plasma reaction time of 15-600 s, and air flow rate of 0.5-5.5 L/min. The results showed that the optimal experimental conditions for Artemia sp inactivation were 16 kV, 60 s, 2.5 L/min, respectively. The concentrations of total residual oxidants and ozone generated by plasma reaction increased with an increase of in voltage and reaction time, and the concentration of generated air did not increase above a certain amount.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.484-489
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• 2005

In order to determine the removal rate of non-biodegradable substances and the change of their structural properties, this study was carried out by an ozone-treatment experiment on leachate collected from the landfill area of D City in Chung chung nam-do and examined the change of the chemical properties of non-biodegradable substances. The main elements of non-biodegradable substances in landfill leachate were benzene, toluene, trichloroethane, trichloroethylene, xylene, etc. and the concentration of toluene was 15.7 mg/L on the average, benzene 7.2 mg/L, trichloroethane 1.1 mg/L, trichloroethylene 0.75 mg/L and xylene 0.5 mg/L. When leachate was treated with ozone for 10 min, 30 min and 60 min, UV absorbance was reduced with the increase of reaction time, and the reduction rate was 38.6% at 60 min. TOC was removed by 13.2% at 60 min. The low reduction rate of TOC may be because TOC reacts indirectly with OH radical produced from reaction with ozone while UV absorbance usually relies on direct reaction between organic matters and ozone molecules. Color was removed by up to 97%, which suggests that ozonation is highly effective in removing coloring elements in leachate. Sixteen kinds of non-biodegradable compounds were found in the leachate and most of them had the characteristic of aromatic hydrocarbon. Among them dibutyl phthalate was identical with a substance included in the list of US EPA, which is classified as a mutagen that may cause the mutation of genes and disorders in chromosomes. In addition, 2,5-Cyclohexadiene-1,4-dione, 1,2-Benzenedicarboxylic acid and butyl octyl ester were found to be similar to substances listed by USEPA. According to the result of analyzing structural changes before and after ozonation using GC-MS, cyclic compounds and aromatic compounds were observed in the original water and aliphatic compounds were newly observed after ozonation. In addition, through ozonation, humic substances of high molecular weight were oxidized and decomposed and produced low-molecular compounds such as aldehyde, ketone and carboxyl acid and highly biodegradable aliphatic carbon, which suggests the bio-degradability of non-biodegradable substances.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.696-702
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• 2005

Ozonation is a disinfection technique of harmful mi-crobes commonly used in the treatment of drinking water. And Biological Activated Carbon (BAC) treatment also provides numerous benefits for drinking water utilities, including removal of micro- pollutants, improved treatment processes. The multiful-stage ozonation and BAC play roles as effective methods for removing several materials in raw water. Water quality variation in Nak dong river and the removal efficiency of viruses by ozonation-BAC process were investigated on pilot scale. During the period of survey, most of water quality parameters including $NH_{4}^{+}-N$ were highly improved after passing through the BAC. The removal efficiency of poliovirus type III in water treatment process using pilot-plant,$ 99.6\% $ of viruses were removed by pre-ozonation, sedimentation and sand filteration process, $ 100\% $ were removed after in BAC filteration step. In the removal survey of viruses by ozonation, ap-proximately $ 61.1\% $ or polioviruses were inactivated by ozone of 0.4 mg/l within 5 min. and $ 100\% $ were inactivated by ozone of 0.8 mg/l over 10 min.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.143-148
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• 2004

This paper shows property conversion of water and removing characteristics of Escherichia coli for discharge tube with $ZrO_2$ beads. At the result of the removal characteristic experiments of Escherichia coli using the discharge tube with $ZrO_2$ beads, because the electric field is also increased when input voltage is increased, the removal characteristic of Escherichia coli was appeared relation connection to input voltage. And if a passing number of test water in discharge tube with $ZrO_2$beads is increased, the removal ratio of Escherichia coli is to be increased because passing number of electric field section is increased. And if diameter of $ZrO_2$beads is increased, the removal time of Escherichia coli is to be decreased because dielectric polalization of $ZrO_2$beads. Also, the removal ratio of Escherichia coli of the discharge tube with $ZrO_2$beads. is appeared higher than the removal ratio of the discharge tube without $ZrO_2$beads. And a satulation punt of ozone and $H_2$ $O_2$generation density inner water was appeared near 60[min].

• 수도
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• v.24 no.4 s.85
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• pp.79-87
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• 1997

In an effort to prevent the formation of DBPs from disinfection and the microbial regrowth in distribution systems, the ozonation followed by biological filtration process in drinking water treatment train has been recently developed as an alternative process to reduce effectively water-born organic matter as precursor. There are, however, insufficient for the consistent information and data about the relation between ozone dosage based on organic surrogate parameter, TOC or DOC and effect of ozonation on BDOC formation. This study is to review critically for the effect of ozonation on biodegradability on the basis of published technical papers including the output from author's research laboratory. It truned out that : 1. ozonation in the presence of organic matter has a tendancy to increase in BDOC content, 2. the rate of BDOC formation was maximum below 1mg $O_3/mg$ DOC of ozone dose, but about maximum content of BDOC was obtainable at the range from 1.5mg $O_3/mg$ DOC to 2mg $O_3/mg$ DOC, 3. from above 1mg $O_3/mg$ DOC, the rate of BDOC formation became slow down, 4. from above 2mg $O_3/mg$ DOC, BDOC formation was quantitatively negligible, In conclusion, it needs further systematic study and research concerned to biodegradability and treatability by ozonation in terms of organic characteristics and experimental conditions because it was hard to find out the consistent experimental data comparable each other that were performed by numbers of research authors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.550-553
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• 2003

This paper was shown water properly conversion and removal characteristic of escherichia coli for discharge tube with $ZrO_2$ beads. At the result of the removal characteristic experiments of escherichia coli using the discharge tube with $ZrO_2$ beads, because the electric field is also increased when input voltage is increased, the removal characteristic of escherichia coli was appeared relation connection to input voltage. And if a passing number of test water in discharge tube with $ZrO_2$ beads is increased, the removal ratio of escherichia coli is to be increased because passing number of electric field section is increased. And if diameter of $ZrO_2$ beads is increased, the removal time of escherichia coli is to be decreased because dielectric polalization of $ZrO_2$ beads. Also, the removal ratio of escherichia coli of the discharge tube with $ZrO_2$ beads. is appeared higher than the removal ratio of the discharge tube without $ZrO_2$ beads. And a salutation point of ozone and $H_2O_2$ generation density inner water was appeared near 60[min].

• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.128-138
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• 2003

The bacterial density of partially processed horticultural crops in the commercial market was relatively high probably due to improper handing or processing. Between crops, the bacterial density was low in peeled garlic and ranged above $10^8cfu{\cdot}g^{-1}fw$ in other crops. Especially in brake fern, the bacterial density was the highest and non food materials such as packing strips were found. There was difference in the effects of ozone-treated water washing treatment between crops. In root crops such as burdock and lotus root, ozone showed positive effect on preventing discoloration as well as lowing bacterial density resulting in the increase of marketing period. Any positive effect was not found when sliced crops were treated over 5 min at $0.3mg{\cdot}L^{-1}$ of dissolved ozone. In lettuce slices, leaf tissues were severely discolored and rapidly soften at $0.3mg{\cdot}L^{-1}$ for 2 min dipping. Ozone was highly effective on inhibiting bacterium propagation and off-flavor. This effect was more stronger in Fischer ligulariata than brake fern, probably due to the difference of tissue thickness. Results indicated that ozone-treated water washing had a strong potential to improve the market quality of partially processed horticultural crops including dried wild greens and sliced root crops.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.272-278
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• 2006

This study was carried out to determine therapeutic the effect of ozonated water therapy on bovine pododermatitis. In addition, bactericidal effect of ozonated water on etiological agent of bovine pododermatitis was examined. The pathohistological examination for the pododermatitis, according to application with ozonated water and ozone ointment was investigated. Thirty healthy cattle were divided two groups(each of 15) : control group(povidone group), treatment group(ozone solution group). Various parameters were evaluated in terms of the lameness score, swelling score, lesion score, WBC count, neutrophil count, pathohistological finding, and antimicrobial action. The decrease of lameness and lesion score were shown in hoof lesions on 14 days after application of ozonated water. Significant decrease of swelling was shown in hoof lesions on 14 days 1Corresponding author after application of ozonated water(p<0.01). In hematological findings, WBC count revealed values within normal range. The number of neutrophils was slightly higher than that of normal, however, this was improved on 14 days after application of ozonated water. In pathohistological findings, recovery was rapid macroscopically and microscopically in the treatment with ozonated water on the hoof lesions and ozonated water was effective. In antimicobial action, bactericidal effect was observed in treatment with ozonated water on the hoof lesions and ozonated water was effective.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.461-467
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• 2005

Phthalate esters is recently considered as an environmental pollutant. This study investigated removal methods of phthalate esters in water environment. On tap water treatment condition with batch test, removal efficiency of coagulation precipitation of one oxidation were $26.6{\sim}33.8%$ and $10{\sim}15%$, respectively. Phthalate esters was effectively removed by the activated carbon adsorption process on tap water treatment condition. The operation of raw water with EBCT of 10 minutes on continuous process satisfied the standard of drinking water by the WHO and US EPA when the concentration of phthalate esters was $100\;{\mu}g/L$. On pilot plant test, coagulation precipitation process got $32{\sim}44%$ of removal efficiency, sand filtration process $6{\sim}10%$ and ozone oxidation process $8{\sim}10%$, respectively. DEP, DBP, BBP and DEHP were not detected after the raw water was processed with activated carbon. The actual survey of phthalate esters removal by advanced water treatment showed that $29{\sim}76%$, $3{\sim}29%$ and $17{\sim}22%$ of phthalate esters were removed on coagulation precipitation process, sand filtration and ozone oxidation process, respectively. DEP, DBP, BBP and DEHP were not detected after the raw water was processed with activated carbon.