• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.5
• /
• pp.869-877
• /
• 2000

A mechanism of ozonation of simulated soil slurry contaminated by phenanthrene and benzo[a]pyrene has been studied under various conditions. The effects of soil media(BS, S, GB), radical scavenger, ozone input ratio(0.17~0.73mg/min), bicarbonate ion, and humic acid were investigated, BS showed the highest removal efficiency in media tested. The generation of OH-radical via the catalytic decomposition of ozone on active sites of the natural sand was confirmed by OH-radical scavenger experiments. The enhanced removal efficiency by OH-radical was indirectly quantified to be about 22%. As initial concentration of humic acid(as sodium salt) was increased, pseudo first-order rate constant ($k_o$) of phenanthrene was decreased from $1.37{\times}10^{-2}s^{-1}$ to $0.53{\times}10^{-2}s^{-1}$. The amount of ozone required to oxidize 80% of the initial mass of phenanthrene(10mg/kg) and benzo[a]pyrene(10mg/kg) was 67.2mg/kg-soil and 48.0mg/kg-soil, respectively.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.25 no.3
• /
• pp.74-99
• /
• 2022

Surface ozone is produced by photochemical reactions of nitrogen oxides(NOx) and volatile organic compounds(VOCs) emitted from vehicles and industrial sites, adversely affecting vegetation and the human body. In South Korea, ozone is monitored in real-time at stations(i.e., point measurements), but it is difficult to monitor and analyze its continuous spatial distribution. In this study, surface ozone concentrations were interpolated to have a spatial resolution of 1.5km every hour using the stacking ensemble technique, followed by a 5-fold cross-validation. Base models for the stacking ensemble were cokriging, multi-linear regression(MLR), random forest(RF), and support vector regression(SVR), while MLR was used as the meta model, having all base model results as additional input variables. The results showed that the stacking ensemble model yielded the better performance than the individual base models, resulting in an averaged R of 0.76 and RMSE of 0.0065ppm during the study period of 2020. The surface ozone concentration distribution generated by the stacking ensemble model had a wider range with a spatial pattern similar with terrain and urbanization variables, compared to those by the base models. Not only should the proposed model be capable of producing the hourly spatial distribution of ozone, but it should also be highly applicable for calculating the daily maximum 8-hour ozone concentrations.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.452-452
• /
• 2021

하천 및 호소수역에 대한 수질오염원이 지속적으로 증가하는 경우에는 일반적인 농도규제 방식으로는 수질개선에 한계가 나타난다. 이를 해결하기 위해 목표 수질 한도 내에서 유역 배출원의 오염물질총량 관리를 목적으로 하는 수질오염총량관리제 개념이 도입되어 단위유역 지자체별 배출부하량을 관리하고 있지만, 지역의 오염원 배출 특성을 고려하지 않은 저감계획은 오히려 유역 내 새로운 오염원으로 전락하여 수질 개선 효과가 나타나지 않을 수 있다. 따라서 효율적인 총량 관리를 위해서는 수계 내 오염원 파악이 필수적이다. 본 연구에서는 수질오염총량제 대상 하천인 굴포천의 수질 오염원 분석을 위해 2016년, 2017년 굴포천 유역 토지이용 자료를 활용하여 수질항목과의 상관성을 파악하고 2016년부터 2020년까지 최근 5년 동안 총량측정망을 통해 측정된 유량 및 수질 자료를 이용해 상류, 중류, 하류 각각의 유량-부하량 관계식을 도출하여 지점별 수질 오염원 특성을 분석하였다. 상관분석 결과, 강우 시 밭과 BOD, SS, T-P는 양의 상관성을 보였고, T-N은 강우, 비 강우 시 관계없이 밭, 논에서 높은 양의 상관성을 보였다. 유량-부하량 관계식 도출 결과, 상류의 경우 BOD, COD, T-P, TOC, SS는 유량이 증가함에 따라 농도가 감소하는 특성을 나타내었는데 이는 2019년 4월 이후 오존처리 재이용수 방류에 따른 유량 증가의 영향이라고 사료 된다. 반면 T-N은 유량이 증가함에 따라 농도가 증가하는 특성을 나타내었는데 이는 오존처리 재이용수의 T-N 농도가 하천의 T-N 농도 보다 높아 발생한 것으로 보인다. 중류와 하류의 경우 BOD, COD, T-P, TOC, SS는 유량이 증가함에 따라 농도가 증가하는 특성을 나타내어 강우 시 비점오염원의 영향이 있는 것으로 보인다. 특히, 하류의 경우 유량이 증가함에 따라 수질 농도가 급격히 증가하여 중류에 비해 비점오염원 영향이 더 큰 것으로 나타났다.

• Korean Journal of Environmental Biology
• /
• v.36 no.1
• /
• pp.90-97
• /
• 2018

This study assessed the effect of ozone to control pathogenic bacteria in inlet water flowing to flounder farms, establishing operational parameters of ozonation at seawater conditions. Hydraulic retention time in a reaction pipeline after ozonation was fixed at 3 minutes in a flow through system. Concentrations of total residual oxidant (TRO) by ozonation were measured according to different ozonation intensities. The oxidant reduction potential (ORP), which is indirect but enables real-time measurement, was measured in relation to TRO values. TRO values were $0.01{\pm}0.01mg\;L^{-1}$ at an ORP range of 320-410 mV, $0.07{\pm}0.02mg\;L^{-1}$ at 600 mV, and $0.16{\pm}0.03mg\;L^{-1}$ at 700 mV. A heterotrophic marine bacteria colony was reduced by 80.6-97.9%, showing the suppression effect of ozonation on total bacteria in inlet water. At an ORP range of 400-500 mV, colonies of heterotrophic marine bacteria, Vibrio spp., and gram negative bacteria were significantly reduced in outlet water from a culture tank with ongrowing flounder (230 g) at a stocking density of $8kg\;m^{-2}$. Especially, Vibrio spp. and gram negative bacteria were seldom found at 400-500 mV. The daily feeding rate was from over 0.7% to total body weight at 300-500 mV, showing better performance than that in the control. The pathogenic bacteria entering the flounder farm were effectively removed when the ORP range to 400 mV or less.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.8
• /
• pp.1070-1075
• /
• 2006

Food materials for kimchi manufacturing were treated by ozone or gamma irradiation to reduce the number of contaminated microorganisms before the manufacturing of kimchi. Counts of total aerobic bacteria, yeast and mold were $10^6{\sim}10^7 and 10^3{\sim}10^4\;CFU/g$ in the food materials, respectively. After treatment with ozone $(3{\sim}6\;ppm), the total aerobic bacteria were reduced to 1 log cycle or more, in a dose-dependent manner. In comparison, gamma irradiation was superior to ozone treatment. Especially, irradiation of 5 kGy fully eliminated the yeast and mold attached in the food materials for kimchi manufacturing. The contents of ascorbic acid and total and reducing sugar were not affected by ozone or gamma irradiation. Taken together, it is suggested that microorganisms contaminated on materials for kimchi manufacturing could be substantially reduced by ozone (up to 6 ppm) and gamma irradiation (up to 5 kGy), without effect on the nutritional contents.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1994.06a
• /
• pp.49-55
• /
• 1994

종래의 가정용냉장고 및 카에어콘 등의 냉매로 널리 사용되던 R-12($CCl_{2}F_{2}$)와 같은 CFC계물질들은 분자내에 포함되어 있는 염소(Cl) 원자로 인해 성층권내의 오존(O$_{3}$)층을 파괴하는 등의 심각한 환경물제를 유발시키는 것으로 확인되었다. 본 연구에서는 가정용냉장고 및 에어콘에 사용 가능한 점도범위의 Polyolester들을 합성하여 이들 각각의 구조와 R-134a와의 상용성 및 마찰, 마모 성능관계를 고찰하였다.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.438-441
• /
• 2000

Ozone has the advantages for the strong oxidant agents. Ozone is widely used as a disinfectant and deodorant in water treatment and biosafety cabinets. We attempted deodorization and disinfection in the piggery using ozone treatment. It was found that ozone affects deodorization of ammonia and decrease of microbial organism in the air. Concentration of ammonia decreased 50 percents and microbial organisms in the air were decreased below 10 percents. It will be useful for the application of the ozone to environmental treatment in the piggery.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.86-88
• /
• 2002

The mathematical model was proposed to simulate ozone transport and remediation in unsaturated soils contaminated with phenanthrene. Soil column experiments were also carried out to calibrate the mathematical model. The experimental results successfully matched with the modeling results in various soil conditions. The model proposed nondimensional fraction factor to reveal reactivity between phenanthrene and gas phase ozone and liquid phase ozone. From sensitivity analysis, the fraction factor and stoichiometric coefficient decreased as water content increased. Simulation results showed increased SOM content retarded the ozone transport and the phenanthrene removal due to increased ozone consumption.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.295-296
• /
• 2003

1990년대 이후 활발히 진행되고 있는 국내 $O_3$ 연구는 대부분 서울 지역에 국한되어 있다. 그러나 대도시의 $O_3$ 농도가 대도시 내에서의 생성 및 소멸에만 기인하는 것이 아니라 대기 운동과 관련된 수평 및 연직 수송에 의한 영향도 중요한 요소임이 많은 연구에서 밝혀지고 있다. 따라서 청정 대기 상태에서 $O_3$의 배경 농도 특성에 대한 연구의 필요성이 증가하고 있다 (서명석 등, 1995). 울릉도 태하는 우리나라의 배경 농도 지역으로 청정 대기 상태에서의 $O_3$ 농도 특성을 연구하기 좋은 지역이다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.04a
• /
• pp.289-290
• /
• 2002

휘발성 유기 화합물(Volatile Organic Compounds, VOCs)은 주로 도장산업, 석유정제 및 저장시설, 화학공업, 자동차 등으로부터 배출되며 광화학적 산화물을 생성시킬 뿐만 아니라 성층권 오존층 파괴나 지구온난화에도 기여함으로써 환경에 악영향을 미치는 물질이다 또한, 대부분의 VOC가 인체에 유해하며 일부 물질들은 발암성을 가지는 것으로 평가되고 있어 배출이 엄격하게 규제되는 물질이다. (중략)