• Title/Summary/Keyword: Ozone

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Evaluation of Advanced Oxidation Process(AOP) as a Pretreatment Process of Biological Activated Carbon in Drinking Water Treatment (정수처리에서 생물활성탄의 전처리로서 고급산화처리법의 평가)

  • Kim Woo-Hang
    • Journal of Environmental Science International
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    • v.8 no.6
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    • pp.725-730
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    • 1999
  • The advanced oxidation process (AOP) using ozone combined with hydrogen peroxide and ultraviolet treatment were evaluated for biodegradable dissolved organic carbon (EDOC) formation and dissolved organic carbon (DOC) removal. Oxidation treatment were conducted alone or combination with ozone, hydrogen peroxide and ultraviolet processes. Ozone dosage of ozone process was varied from $0.5mg/l{\ell}\cdot}min$ to $5mg/{\ell}{\cdot}min$. Ozone/hydrogen peroxide process was done using $20mg/{\ell}{\cdot}min$ of hydrogen peroxide concentration. Ozone/ultraviolet process was irradiated with $12mW/cm^2$ of density and 254nm. Ozone dosage was varied from $0.5mg/{\ell}{\cdot}min$ to $5mg/{\ell}{\cdot}min$ at the ozone/hydrogen peroxide and ozone/ultraviolet processes too. Contact time of all the process was 20 minutes. Oxidation treatment were performed on microfiltration effluent samples. BDOC formation was reached to an optimum at ozone dosage of $1.5mg/{\ell}{\cdot}min$ in the ozone/hydrogen peroxide process and $1mg/{\ell}{\cdot}min$ in ozone/ultraviolet process, after which BDOC formation was decreased at higher ozone dosages. But BDOC formation was increased with ozone dosages increasing in ozone process. The efficiency of DOC removal was higher AOPs than ozone process. Ozone/ultraviolet proces was the highest for DOC removal efficiency in each process. THMFP. removal efficiency by ozone/ultraviolet process was higher than that by each of ozone process and ozone/hydrogen peroxide process.

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Assessing Factors Linked with Ozone Exceedances in Seoul, Korea through a Decision Tree Algorithm

  • Park, Sun-Kyoung
    • Journal of Environmental Science International
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    • v.25 no.2
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    • pp.191-216
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    • 2016
  • Since prolonged exposure to elevated ozone ($O_3$) concentrations is known to be harmful to human health, appropriate control strategies for ozone are needed for the non-attainment area such as Seoul, Korea. The goal of this research is to assess factors linked with the 1-hour ozone exceedance through a decision tree model. Since ozone is a secondary pollutant, lag times between ozone and explanatory variables for ozone formation are taken into account in the model to improve the accuracy of the simulation. Results show that while ozone concentrations of the previous day and $NO_2$ concentrations in the morning are major drivers for ozone exceedances in the early afternoon, meteorology plays more important role for ozone exceedances in the late afternoon. Results also show that a selection of lag times between ozone and explanatory variables affect the accuracy of predicting 1-hour ozone exceedances. The result analyzed in this study can be used for developing control strategies of ozone in Seoul, Korea.

Synoptic Weather Patterns and Variation of Ozone Concentrations Association with High Ozone Days at Five Major Cities in Korea (고농도 오존이 발생하는 날의 종관 기상 패턴과 주요 5대 도시별 오존 농도 변화)

  • 김유라;윤일희;김희종
    • Journal of Environmental Science International
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    • v.10 no.6
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    • pp.437-444
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    • 2001
  • The characteristic features of surface ozone concentration and the forecasting procedure of high ozone days have been studied. The ozone concentration was continuously measured during 3 years (1997~1999) at air quality monitoring stations in five major cities in Korea. The diurnal variation of surface ozone concentration on high ozone days is characterized by low ozone concentration at night. The ozone concentration Increases continuously after sunrise, In reach a peak at 1500~1600 LST. Thereafter it decreases steadily to a low concentration at sunset. The diurnal and annual maximum of the surface ozone concentration at Seoul were observed in May and June, respectively. The favorable synoptic condition for the high ozone day is divided into 4 different synoptic weather patterns: a high-pressure system from the Sea of Okhotsk, the Pacific subtropical high extending westward, a moving high-pressure system covering the Korean peninsula. and a synoptic system In front of a typhoon. Most of high ozone days occur under the high pressure system in Korea.

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Characteristics of nocturnal maximum ozone and meteorological relevance in Pusan coastal area (부산 연안역의 야간 고농도 오존 발생 특성과 기상학적 관련성)

  • 전병일
    • Journal of Environmental Science International
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    • v.8 no.3
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    • pp.287-292
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    • 1999
  • This study was performed to investigate the characteristics of nocturnal maxiumu ozone occurrence and the meteorological relevance using to hourly ozone data and meteorological data for 1995~1996 in Pusan coastal area. Kwangbokdong showed the highest occurrence of nocturnal maximum ozone as 36.9%, and Deokcheondong showed the lowest occurrence(9.2%) for research period in Pusan. The occurrence rates of nocturnal maximum ozone concentration were decreased toward land area. The low maximum temperature, high minimum temperature, low diurnal range, high relative humidity, high wind speed, high could amount, low sunshine and low radiation were closely related to the main meteorological characteristics occuring the nocturnal maximum concnetration of ozone. It was shown that normal daily variation of ozone concentration by strong photochemical reaction at the before day of nocturnal maximum ozone. The concnetration of nocturnal maximum ozone were occured by entrainment of ozone from the upper layer of developed mixing layer. There are no ozone sources near the ground at night, so that the nighttime ozone should be entrained from the upper layer by forced convection.

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Improvement of Ozone Process for Removal Rate Elevation of Humic Acid (부식산 제거율 향상을 위한 오존공정의 개선에 관한 연구)

  • Lee, Yu-Mi;Son, Yil-Ho;Rhee, Dong-Seok
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.25-29
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    • 2007
  • Ozone alone, Ozone/GAC, Ozone/$H_2O_2$ and Ozone/GAC/$H_2O_2$ processes were introduced for treatment of humic acid, which is a representative refractory organic compound. $H_2O_2$ and GAC used as catalysts for experiment. The treatment efficiencies of humic acid in each process were analyzed for pH variation, DOC removal, and $UV_{254}$ decrease. $UV_{254}$ decrease in Ozone/GAC and Ozone/GAC/$H_2O_2$ processes were the highest with about 93%, and Ozone alone and Ozone/$H_2O_2$ processes were 88%. DOC removal in Ozone/GAC/$H_2O_2$ process was the highest with 71%. Removal by Ozone/GAC, Ozone alone, and Ozone/$H_2O_2$ processes were 66%, 39%, and 47%, respectively.

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Effect of Ozone Treatment on the Quality of Soybean Sprouts 2. Optimum Conditions of Ozone Treatment during Soaking of Soybean for Quality Enhancement of Soybean Sprouts (콩나물의 품질에 미치는 오존처리 효과 2. 콩의 수침중 오존처리의 최적화)

  • 김일두;박미자
    • Korean Journal of Food Preservation
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    • v.5 no.2
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    • pp.177-185
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    • 1998
  • For the purpose of enhanceing soybean-sprouts quality, the optimum conditions for ozone treatment of soybean during soaking before cultivation at 18~2$0^{\circ}C$ were evaluated with ozone concentration, treatment time and treatment frequency by response surface methodology. Germination rates of cleaned soybean by ozone water in the conditions of solubilized-ozone concentrations of 0.15 to 0.35ppm, ozone-treatment frequency of 1.5 to 2.3 times and ozone-treatment time of 30 to 36min. increased 18.8 to 24.0% for the control products. And, length of hypocotyl in conditions of 0.12 to 0.33ppm, 1.7 to 2.7 times and 45 to 90min. were also increased by 69.36 to 79.40%. On the other hand, weight of roots with ozone treatment were decreased in the conditions of solubilized ozone concentrations of 0.1 to 0.2ppm and ozone-treatment time of 30 to 57min. But, ozone-treatment frequency did not affected root growth. Putrefaction rates of the control were 5 to 15%, but those of ozone-treated samples during cultivation did not show. The overall optimum conditions for above 16% germination rates, above 9% hypocotyl yields compared to the control samples and below 98% of the control root weight were solubilized-ozone concentrations of 0.25 to 0.30ppm, ozone-treatment time of 43 to 49min. and ozone-treatment frequency of one time.

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Characteristics of Surface High Ozone Concentration on Pusan Coastal area, Korea (부산 해안지역의 고농도 오존 발생 특성에 관한 연구)

  • 전병일
    • Journal of Environmental Science International
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    • v.9 no.4
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    • pp.295-302
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    • 2000
  • This study was conducted to investigate the characteristics of surface ozone concentration and occurrence of high ozone concentration using hourly ozone, nitrogen dioxide and meteorological data for 1997~1998 in Pusan coastal area. Monthly mean ozone concentration was the highest at Dongsamdong in Spring(35.4ppb), at Kwangbokdong in Fall(25.1ppb) and the lowest Dongsamdong(22.2ppb) and Kwangbokdong(16.0ppb) in Winter. Relative standard deviation indicating clearness of observation site was 0.42 at Dongsamdong and 0.49 at Kwangbokdong that is similar to urban area. The diurnal variation of ozone concentration of Dongsamdong and Kwangbokdong showed maximum at 1500~1600LST and minimum 0700~0800LST that typical pattern of ozone concentration. In ozone episode period(Sept. 10~15, 1998), diurnal change of ozone concentration was very high, and ozone concentration was related to meteorological parameters such as temperature, relative humidity, wind speed, cloud amount and radiation on a horizontal surface. During the episode days peak ozone concentrations are much higher than the normal values, wind speeds are always lower, and solar radiation is high with the exception of the September episode.

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Photochemical Analysis of Ozone Episodes in the Metropolitan Area of Seoul During the Summer 2004 (2004년 여름 서울에서 발생한 고농도 오존 사례의 광화학적 분석)

  • Shon, Zang-Ho
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.3
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    • pp.361-371
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    • 2006
  • This study examines ozone episodes occurred during the intensive sampling periods (Jun. 1-30, 2004) in the air of Seoul metropolitan area. During that period, there were 8 events (or days) in which 1 hr averaged ozone concentrations were greater than 100 ppbv. The photochemical analysis of ozone chemistry (i.e., budget and formation and destruction strengths of ozone) was carried out using a photochemical box model. Peaks in diurnal ozone variations during ozone episode periods occurred were concurrent with the sudden change of the slope of $NO_{2}/NO$ ratio, suggesting significant correlation with photochemical reactivity. In addition, the ozone peaks were concurrent with high concentrations of ozone precursors, peroxy radicals of $HO_{2},\;CH_{3}O_{2},\;and\;RO_{2}$. High ozone levels during the ozone episodes are likely to be affected by ozone destruction rate.

Disinfective Properties and Ozone Concentrations in Water and Air from an Ozone Generator and a Low-temperature Dielectric Barrier Discharge Plasma Generator (오존발생기와 저온 유전체장벽 플라즈마를 이용한 오존 발생 및 살균력)

  • Lee, Young Sik;Jeon, Hyoung-Joo;Han, Hyung-Gyun;Cheong, Cheong-Jo
    • Journal of Environmental Science International
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    • v.22 no.8
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    • pp.937-944
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    • 2013
  • Ozone concentrations in water and air, and resulting disinfective properties, were measured following generation by either an ozone generator or a low-temperature dielectric barrier discharge plasma generator. In freshwater, ozone concentrations of 0.81 and 0.48 mg/L $O_3$ were observed after the ozone and plasma generators had been operated for five minutes, respectively. Higher levels of dissolved $O_3$ were attained more easily with the ozone generator. In seawater, both systems were capable of creating concentrations greater than 3.00 mg/L $O_3$ after 5minutes of operation. Higher ozone levels were attained more easily in seawater than in freshwater. Rates of bacterial sterilization in seawater after three minutes were 96% and 88%, using the plasma and ozone generators, respectively. In freshwater, higher concentrations of ozone were released into the atmosphere by the ozone generator than by the plasma generator. In creating equivalent levels of dissolved ozone in freshwater, the plasma generator released 4.5 times more ozone into the atmosphere than did the ozone generator. This shows that ozone generators are more effective than plasma generators for creating ozonated water. For the same concentration of dissolved ozone in seawater, more ozone was released into the atmosphere using the ozone generator than using the plasma generator. Therefore, with regard to air pollution, plasma generators seem to be less expensive than ozone generators.

Evaluating Effective Volume and Hydrodynamic Behavior in a Full-Scale Ozone Contactor with CFD Simulation (전산유체역학을 이용한 실규모 오존 접촉에서의 수리거동과 유효 체적 평가에 관한 연구)

  • Park, No-Suk;Mizuno, Tadao;Tsuno, Hiroshi;Bea, Chul-Ho;Lee, Seon-Ju
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.5
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    • pp.656-665
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    • 2004
  • An Ozone reaction model combined with CFD(Computational Fluid Dynamics) technique was developed in this research, in the simulation of ozonation, hydrodynamic behavior as well as reaction model is important because ozone is supplied to treated water as gas ozone. In order to evaluate hydrodynamic behavior in an ozone contactor, CFD technique was applied. CFD technique elucidated hydrodynamic behavior in the selected ozone contactor, which consisted of three main chambers. Three back-mixing zones were found in the contactor. The higher velocities of water were observed in the second and third compartments than that in the first compartment. The flow of the opposite direction to the main flow was observed near the water surface. Based on the results of CFD simulation, the ozone contactor was divided into small compartments. Mass balance equations were established were established in each compartment with reaction terms. This reaction model was intended to predict dissolved ozone concentration, especially. We concluded that the model could predict favorably the mass balance of ozone, namely absorption efficiency of gaseous ozone, dissolved ozone concentration and ozone consumption. After establishing the model, we discussed the effect of concentration of gaseous ozone at inlet, temperature and organic compounds on dissolved ozone concentration.