• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.663-669
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• 2005

The aim of this study was to investigate the ozone decay pattern for the effective application of ozone in drinking water treatment. In order to measure the ozone decomposition in water, ozone measuring instrument was developed with flow injection analysis (FIA) method. From the result of continuous residual ozone concentration in water, it was confirmed that the ozone decay pattern was divided with instantaneous ozone demand(I.D) and pseudo first-order rate($k_c$) phases, which were influenced by the variation of ozone dose. The empirical model obtained from I.D and $k_c$ values enabled us to predict the residual ozone concentration according to the reaction time, showing the high correlation between model and experimental values. The concentration of OH radical and $R__{ct}$ could be indirectly measured by OH radical probe compound. In both I.D and $k_c$ phases, the production pattern of OH radical could be observed, which was also affected by the variation of ozone dose. Finally, it was confirmed that the ozone consumption rate was varied according to the each drinking water treatment process and seasoning. Therefore, the optimum position and dosage of ozone have to be selected by considering various factors.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1997.10a
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• pp.67-67
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• 1997

정수공정은 "원수 -1 침사지 1 전염소 -1 전오존 -1 침전지 1 여과지 1 후오존 1 GAC 4 후염소 1 가정수"로 이루어져 있으며 전처리 공정으로 염 소와 오존을 주입하게 되는데, 여기서 전염소 처리 공정으로 인해 잔류 유리염 소가 수중의 유기물질과 반웅하여 유해성 유기염소 화합물 (i.e.. Trihalomethane, Haloacetonitriles, Chlorophenol 등)을 생성하는 것으로 알려져 있다. 이러한 이유로 고도 정수처리 공정에서는 강한 산화력을 지닌 대체 산화 제로서 오존을 이용하고 있다. 전오존 처리공정은 OOC와 탁도 제거에 있어 응 집제 주입량을 감소시키는 것과 더불어 전오존 효과 (산화, 생분해 증대, 살균 등)를 얻을 수 있는 것으로 알려져 왔다. 그러나 낙동강과 같이 유기물이 많은 원수에 과다한 오존이 주입되면 수중 의 유기물이 저분자화 또는 응집이 어려운 오존 산화물로 변화하여 응집제의 소비가 많아지게 된다. 실제, 오존을 응집 효과에 대해서 pilot plant로 운전한 결과 전오존에 의해 입자성 물질의 제거 효율은 향상된 반면에 유기물 제거는 뚜렷한 효과를 볼 수 없었다고 보고되었다 (류, 1997). 본 연구에서는 물금 지역의 원수와 응집-침전 공정까지 거치는 각각의 처 리수에 대해서 전처리가 응집에 미치는 영향을 천연유기물질 (NOM)의 조성 변화로 파악하였다. 그 방법으로 천연유기물질 (NOM)을 XAD-1, -4 수지를 이 용하여 소수성 물질 (hydrophobic components)과 친수성 물질 (hydrophilic components)로 분리 및 농축하여 용존 유기물이 처리 과정에서 어떻게 변화하 는지를 조사하여 개선된 상수 처리 시스템을 설계하는데 기초 자료를 제공하고 수질 관리 분야에서도 적용하고자 하였다. 상수원수인 물금 지역의 소수성 물질(hydrophobic components)은 75~80%, 친수성 물질(hydrophilic components)은 30~33%정도의 분포를 보였고, 전염소 및 전오존 공정을 거친 처리수에서는 각각 62.2-62.8%, 43.9~49.0% 및 50~ 55%, 40~57% 정도의 분포를 보였다. 그리고 웅집-침전을 거친 처리수에서는 그 분포가 77~82%, 24-48%였다. 전주리 공정을 통하여 소수성 물질(byoghobic components)의 분포가 감 소하는 것을 볼 때 전염소 및 전오존 처리가 용존유기물의 응집에는 오히려 역 효과를 나타내는 것으로 판단된다. 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.330-336
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• 2005

The ozone injection method was proposed to improve the catalytic process for the removal of nitrogen oxides ($NO_x$). Nitric oxide (NO) in the exhaust gas was first oxidized to nitrogen dioxide ($NO_2$) by ozone produced by dielectric barrier discharge, and then the exhaust gas containing the mixture of NO and $NO_2$ was directed to the catalytic reactor where both NO and $NO_2$ were reduced to $N_2$ in the presence of ammonia as the reducing agent. A commercially available $V_2O_5-WO_3/TiO_2$ catalyst was used as the catalytic reactor. The $NO_2$ content in the mixture of NO and $NO_2$ was changed by the amount of ozone added the exhaust gas. The effect of reaction temperature, initial $NO_x$ concentration, feed gas flow rate, and ammonia concentration on the removal of $NO_x$ at various $NO_2$ contents was examined and discussed. The increase in the content of $NO_2$ by the ozone injection remarkably improved the performance of the catalytic reactor, especially at low temperatures. The present ozone injection method appears to be promising for the improvement of the catalytic reduction of $NO_x$.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.743-750
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• 2008

In water treatment plant the Dissolved Ozone Flotation(DOF) System may be employed because this system has various abilities, such that it can remove SS using microbubbles, and it can exert strong oxidation power in removing taste and odor, color, and microbial agents. In order to investigate effectiveness of the DOF system in water treatment, removal characteristics of various water quality parameters were observed depending on the different levels of ozone concentrations. Removal efficiencies of water quality parameters in DOF system were compared with those in DAF(Dissolved Air Flotation) system and in CGS(Conventional Gravity Settling) system. Optimum ozone dose obtained in the pilot experiments was 2.7 mg/L. With increasing ozone dose higher than 2.7 mg/L, removal rates of turbidity, KMnO$_4$ consumption, UV$_{254}$ absorbance, and TOC were reversely lowered. High concentration of ozone dissociate organic matter in water, so that increasing dissolved organic level in effluent. Removal rates of water quality parameters at optimum ozone dose were obtained, such that removal rates of turbidity, KMnO$_4$ consumption, TOC, and UV$_{254}$ asorbance were 88.9%, 62.9%, 47%, and 77.3% respectively. Removal rate of THMFP was 51.6%. For all the parameters listed above, the DOF system was more effective than the DAF system or the CGS system. It is found that the DOF system may be used in advanced water treatment not only because the DOF system is more efficient in removing water quality parameters than the existing systems, but because the DOF system is also required smaller area than the CGS system for the treatment plant.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.3-15
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• 1999

This paper includes the basic experimental results performed for developing an innovative and technologically feasible process wherein gaseous ozone, a powerful oxidant. is injected directly into vadose zone by which in-situ chemical degradation of semi- or, non-volatile petroleum product such as diesel fuel is derived. As ozone gas injected continuously(50mL/min, 119.0$\pm$6.1mg/L) into soil packed columns artificially contaminated with diesel fuel(initial concentration 1,485mg-DRO/kg/soil), the removal rates at the inlet and outlet point of 14hrs-operated column are 87.9% and 100.0%, respectively. On the other hand, soil vapor extraction system showed less than 30% of removal rates of residual diesel both at the inlet and outlet samples under the same experimental conditions which confirms the limited treatability of SVE in diesel contaminated soil.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1825-1832
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• 2000

Column experiments were conducted by using soil columns, to investigate feasibility and efficiency of in-situ ozone enhanced remediation for diesel-contaminated soil. The injection of gaseous ozone into soil column revealed the enhanced decomposition of ozone due to the catalytic reaction between ozone and metal (e.g., Fe, Mn etc.) oxides as evidenced by as much as 25 times shorter half-life of ozone in a sand packed column than in a glass beads packed column. Substantial retardation in the transport of and the consumption of ozone were observed in the diesel contaminated field soil and sand packed columns. After 16 hrs ozonation, 80% of the initial mass of diesel (as diesel range organic) concentration of $800{\pm}50mg/kg$, was removed under the conditions of the flow rate of 50mL/min and $6mg-O_3/min$. Whereas, less than 30% of diesel was removed in the case of air injection. Analysis of the residual TPH(total petroleum hydrocarbon) and selected 8 aliphatics of diesel compounds in the inlet and the outlet of the column confirmed that diesel nonselectively reacted with ozone and then shifted to lower carbon numbered molecules. Water content also was found to be an important parameter in employing ozone to the hydrocarbon-contaminated soil.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1134-1140
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• 2010

Ozonation is a promising process that can effectively reduce the occurrence of micropollutants and pathogen in water. This study investigated the performance of ozonation for the removal of pharmaceuticals and personal care products (PPCPs) in secondary effluent from wastewater treatment plant. Moreover, the disinfection potential of ozonation applied for PPCPs removal was discussed. Secondary effluent filtered by sand filter was used for tested water, and ozonation was performed under 2, 4 and 6 mg/L of ozone doses. As a result, 6 mg/L of ozone dose (ozone consumption : 4.4 mg/L) was essential for the effective removal of 37 PPCPs in tested water. Several previous studies showed that the operation condition could achieve approximately 3 log inactivation of total coliform and enteroviruses. On the other hand, dissolved ozone concentration in tested water increased by 1.8 mg/L under 6 mg/L of ozone dose, probably resulting in the increase of bromate formation potential. This result implies that as alternatives to suppress the bromate formation potential during the oxidation of PPCPs by ozone, investigations on advanced oxidation processes are required.

• Membrane Journal
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• v.14 no.1
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• pp.66-74
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• 2004

Total resistance of membrane in a micro-filtration system using a metal membrane was mainly attributed to the permeate resistance of cake layer($R_c$), which was formed by deposited particles from the physico-chemical interactions of solids on membrane surface. Intermittent back ozonation was highly effective than the air backwashing for fouling reduction. As far the operational effect, under same ozone injection, the increase of gas flow-rate was more favorable than the increase of injection time far the recovery of permeation flux. As the filtration time was longer, the effect of flux recovery by intermittent back-ozonation decreased. Therefore, it is preferable to operate membrane cleaning before the foulant is consolidated on membrane surface.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1052-1057
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• 2005

Recently, the ozone treatment of wasting activated sludge has become one of the effective and feasible process for the sludge reduction. The objective of this study is to investigate the availability of ozonized wasting sludge on external carbon sources 13r phosphorus release. Experiment results showed that the ozone treatment of activated sludge could produce a large amount of VFA such as acetic acid and isobutyric acid. For example, 50.24 mg/L acetic acid was produced with the ozone dose of 0.05 g $O_3/g$ SS, and 123.56 mg/L acetic acid with 0.5 g $O_3/g$ SS. The higher ozone dose was applied, the more VFA was produced from sludge reduction into a limited point. Finally, using ozonated sludge as only carbon source, the batch experiment, to measure phosphorus release rate in anaerobic condition were performed. The specific phosphorus release rates were investigated as 0.94, 1.37, 1.48, 1.68 mg P/g VSS/hr with ozone dose of 0.05, 0.1, 0.2, 0.5 g $O_3/g$ SS, respectively. Considering the degree of mineralization, VFA production, phosphorus release rate, and economical aspect, the optimal ozone dose for sludge reduction and using carbon sources ranged from 0.05 to 0.1 g $O_3/g$ SS.

• Journal of Veterinary Clinics
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• v.22 no.4
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• pp.314-317
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• 2005

The potential therapeutic effect of ozone gas on bovine mastitis was investigated. Eighteen quarters from 18 lactating cows with chronic mastitis were included. The 18 quarters were assigned to the control group (treatment with antibiotics for 3 days), experimental group I (0.1 ppm ozone treatment, for 7 days) and experimental group II (1ppm ozone treatment, for 3days). In experimental group I, milk somatic cell counts were lower on day 7 after ozone treatment, compared to the pretreated counts, but were higher than the control counts. In experimental group II, somatic cell counts were significantly decreased (p<0.05) on day 7 compared to the pretreatment counts, and they were lower than the control counts. There were no changes in leukocyte, neutrophil, or lymphocyte numbers, N/L ratios, N/L ratios, or serum total protein in the control and experimental groups. We concluded that ozone gas treatment(1ppm for 3days) might be effective for treatment of bovine mastitis.