• 한국환경보건학회지
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• 제29권1호
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• pp.74-83
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• 2003

Microcystin, stable compounds with circular heptapeptides, is presented inside cyanobacterial cell. So far, over 30 types have been known to exist and microcystin-LR, RR among them are the most potent toxin compound. By this reason, a strong oxidant, ozone was used in this study to remove the microcystins produced by cyanobacteria. Removal efficiency of microcystin at M water treatment plant was also evaluated. Microcystin concentration was determined by protein phosphatase inhibition assay. The results showed that dissolved microcystin in raw water detected in the range of 0.011-0.028 ㎍ Microcystin-RR equivalent/l. Above 98% of microcystin was removed through overall treatment system. Therefore, the water treatability of M treatment plant seemed to be excellent. Removal efficiency of microcystin according to unit process varied as characteristics of raw water such as DOC, UV/sub 254/ and turbidity. Removal efficiency of microcystin by ozonation was investigated in laboratory according to contact time and ozone dose. Dissolved microcystin was increased by twice fold according to ozone contact time, but increased by fifth fold according to ozone dose. So, changing of ozone dose more affected microcystin release than changing of ozone contact time. Behavior of microcystin by ozonation was similar to that of DOC, and residual ozone concentration gave influence to removal ratio of microcystin. In conclusion, single ozone treatment wasn't effective on microcystin removal in case of water containing a lot of cells. Therefore, it's more effective to use ozonation process after the removal of cyanobacterial cells in advance.

• 한국작물학회지
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• 제49권2호
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• pp.110-115
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• 2004

Rice (Oryza sativa L.) plants were cultivated to examine changes in antioxidative defence mechanism induced by elevated ozone levels. Catalase activities in tolerant Jinpumbyeo and susceptible Chucheongbyeo under ozone fumigation were reduced at 5 hrs and 3 hrs after ozone fumigation, respectively. With the increased ozone supply, peroxidase activity in Jinpumbyeo was steadily enhanced whereas in Chucheongbyeo it was not changed. Four SOD-isozymes were detected by NBT staining of native-PAGE. Two isozymes of them were obviously induced by ozone supply, particularly in Jinpumbyeo. The continuous ozone fumigation increased remarkably putrescine levels in leaves whereas it did not affect the levels of spermidine and spermine. In this study, it was implied that ozone in cell inhibits strongly diamine oxidase and thus promotes ethylene biosynthesis which will cause the senescence in rice plants.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.31-34
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• 2004

Feasibility of electrokinetic(EK)-Fenton process and Ozone chemical oxidation were investigated for tile removal of organic contaminants and heavy metals from the contaminated soil. In EK-Fenton process, accumulated electroosmotic flow(EOF) was 80 L for 26 days. Removal efficiency of TPH, As, and Ni were 61%, 36%, and 47%, respectively. The concentration of As was high near the anode due to the transport of anionic As toward the anode, while the concentration of Ni was high near the cathode by the movement of cationic Ni to the cathode. Field scale application of in-situ ozonation was carried out for removal of TPH in 3-D test cell (3 m$\times$2 m$\times$2 m). After 25 days of ozone injection, more than 80% of removal rate was observed through the test cell.

• 상하수도학회지
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• 제18권1호
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• pp.59-65
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• 2004

The change of the microbial community structure in excess sludge of different sewage treatment plants by ozone treatment was investigated by quinone profiles. The resulting ozone dosage ranged from 0.1 to $0.4gO_3/gTS$. In terms of overall sludge reduction, more than 50% reduction of the total sludge mass could be achieved by ozone treatment at $0.4gO_3/gTS$. Quinone concentration and type in sludge of different treatment plants were remarkably decreases with increasing ozone dose. Ubiquinones(UQs)-8, -10 and MK-8 were still remained in the ozonized sludge at $0.4gO_3/gTS$. The results of this study showed that the remaining microorganisms belong to UQs-8, -10 and MK-8 were difficult to destruct cell membrane or wall by ozonation. Fecal Streptococci and Salmonella were not detected at ozone dose of $0.2gO_3/gTS$, but Fecal Coliform was not detected at ozone dose of $0.4gO_3/gTS$.

• 상하수도학회지
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• 제19권6호
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• pp.800-808
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• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• 한국환경농학회지
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• 제5권2호
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• pp.106-112
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• 1986

Ozone가스에 의(依)한 수도엽(水稻葉)의 생화학적변화(生化學的變化)를 구명(究明)하기 위(爲)하여 수도(水稻)의 서광(曙光)벼와 진주(眞珠)벼를 공시(供試)하여 분벽기(分蘗期)에 0.3ppm의 Ozone가스를 0, 1, 3, 5, 시간별(時間別)로 접촉(接觸)한 후(後) 피해엽율(被害葉率)과 효소(酵素)의 활성(活性), Flavonoid, 단백질함량(蛋白質含量)을 조사(調査)한 결과(結果)는 다음과 같다. 1. Ozone가스의 급성피해증상(急性被害症狀)은 은백색(銀白色)의 반점(斑點)이고 만성피해증상(慢性被害症狀)은 적갈색(赤葛色)의 반점(斑點)으로 나타났다. 2. 피해엽(被害葉)의 적갈색(赤褐色)의 피해반점(被害斑點)은 주(主)로 잎의 전면(前面) 기공주변(氣孔周邊)에 발생(發生)되었다. 3. 서광(曙光)벼가 진주(眞珠)벼보다 엽피해율(葉被害率)이 적었다. 4. Ozone가스 접촉(接觸)으로 엽중(葉中) peroxidase 및 polyphenol oxidase활성(活性)이 증가(增加)되었다. 5. 피해후(被害後) 시간(時間)이 경과(經過)함에 따라 진주(眞珠)벼가 서광(曙光)벼보다 peroxidase활성(活性)이 높았다. 6. peroxidase를 전기영동(電氣泳動)한 결과(結果) 대조엽(對照葉)과 피해엽간(被害葉間)에 band의 차이(差異)가 있었다. 7. Ozone가스피해(被害)로 엽내(葉內) Flavonoid 및 환원당함량(還元糖含量)이 증가(增加)하고 단백질함량(蛋白質含量)이 감소(減少)하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권12호
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• pp.673-678
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• 2000

The dielectric barrier discharge(DBD) is a common method to create a nonthermal plasma in which electrical energy is used to create electrons with a high average kinetic energy. The unique aspect of dielectric barrier discharges is the large array of short lifetime(10ns) silent discharges created over the surface of the dielectric. A silent discharge is generated when the applied voltage exceeds the breakdown voltage of the carrier gas creating a conduction path between the applied electrode and grounded electrode. As charge accumulates on the dielectric, the electric field is reduced below the breakdown field of the carrier gas and the silent discharge self terminates preventing the DBD cell from producing a thermal arc. In fact, the most significant application of dielectric barrier discharges is to generate ozone for contaminated water treatment. Therefore, experiments were perfomed at 1∼2[bar] pressure using a coaxial geometry single dielectric barrier discharge for ozone concentrations and energy densities. The main result show that the concentration and efficiency of ozone are influenced by gas nature, gas quantity, gas pressure, supplied voltage and frequency.

• 한국환경과학회지
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• 제18권4호
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• pp.445-450
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• 2009

In this study, the fundamental experiments were performed for catalytic oxidation of NO (50 ppm) on $MnO_2$ in the presence of ozone. The experiments were carried out at various catalytic temperatures ($30-120^{\circ}C$) and ozone concentrations (50-150 ppm) to investigate the behavior of NO oxidation. The honeycomb type $MnO_2$ catalyst was rectangular with a cell density of 300 cells per square inch. Due to $O_3$ injection, NO reacted with $O_3$ to form $NO_2$, which was adsorbed at the $MnO_2$ surface. The excessive ozone was decomposed to $O^*$ onto the $MnO_2$ catalyst bed, and then that $O^*$ was reacted with $NO_2$ to form $NO_3^-$. It was found that the optimal $O_3$/NO ratio for catalytic oxidation of NO on $MnO_2$ was 2.0, and the NO removal efficiency on $MnO_2$ was 83% at $30^{\circ}C$. As a result, NO was converted mainly to $NO_3^-$.

• 한국정밀공학회지
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• 제28권10호
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• pp.1217-1223
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• 2011

In this paper, the dielectric barrier discharge plasma generator has been studied for producing of the high concentration ozone gas. Proposed plasma generator has the structure of extremely narrow discharge air gap(0.15mm) in order to realize the high electric field discharge. We investigate the performance of the dielectric barrier discharge plasma generator experimentally and the results show that the generator has very high ozone concentration characteristics of 13.7[wt%/$O_2$] at the oxygen flow rate of 1[${\ell}$/min] of each discharge cell. So, we confirmed that the proposed plasma generator is suitable for the high concentration ozone production facility of the eco-friendly ozone functional water cleaning system in the electronic components cleaning process.

• Toxicological Research
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• 제20권1호
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• pp.71-82
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• 2004

Changes in cell cycle control in the lungs and liver of the B6C3F1 mice (20 males per each group) exposed to ozone (0.5 ppm), 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 1.0 mg/kg), and dibutyl phthalate (DBP, 5,000 ppm) after 52 weeks were examined through Western, Northern blot, and immunohistochemistry based on alterations in protein expression levels of G1/S checkpoints (cyclin D1, cyclin E, and PCNA), G2/M checkpoints (cyclin B1, cyclin G, and cyclin A), negative regulators (p53, p21, GADD45, and p27), and positive regulator (mdm2). Expression levels of cyclins D1, E, G, PCNA, mutant p53, and mdm2 proteins were higher in the lungs and livers treated with combination of toxicants than in those treated with ozone only. Expression levels of the wild-type and mutant p53, p21, GADD45, p27, and mdm2 proteins and mRNAs were higher in toxicant-treated groups than those of the control. Immunohistochemical analysis revealed staining intensities of the PCNA, cyclin D1, c-myc and mdm2 protein- treated lungs and livers were stronger than those of the control group. Our results showed that combined treatment of ozone with NNK/DBP altered the cell cycle control through instability of the wild-type p53 gene. Such pivotal p53-mediated cell cycle alterations may be responsible for the toxicity observed under our experimental condition. These results may be applied to risk assessment of mixture-induced toxicity.