• 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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• 제11권2호
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• pp.94-104
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• 1997

Ozone Treatment is getting a common process in a water treatment plant all over the nation. Especially an advanced water treatment using ozone and biofiltration has been a typical method in the regions where using the Nak-Dong River as a drinking water source. The effectiveness of ozone treatment in a continuous flow contact system was investigated with sand filtered water of the Nak-dong River. Pilot tests of the experiments were performed three times of the year like June, August, and October 1995. Most degradable organics of sand filtered water were oxidized in the first and second contact chamber of the system. Ozone treatment was effective for the removal of UV254 absorbance. However, Noticeable removals of $KMnO_4$ demand and TOC(Total Organic Carbon) were occurred when their concentrations exceeded about 5mg/l. The organics causing $KMnO_4$ demand and TOC were degraded into lower molecular matter in an early stage of the ozone contact in the system. Dissolved oxygen concentration was increased after ozone treatment.

• 상하수도학회지
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• 제22권5호
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• pp.511-516
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• 2008

Since 1989, Advanced drinking water treatment processes began to build in Korea, especially the water treatment plants around the Nak-dong river stream due to sequential pollutant accidents. Moreover, Advanced drinking water treatment processes, ozone and GAC, are again to be built in water treatment plants around Han-river stream to control taste and odor, micro pollutants. However, there are still a lot of discussion to decide the processes to apply for advanced treatment. Thus there are still need to understand clearly on the cost evaluation of each advanced treatment processes. The cost evaluation was accomplished based on the data of six water treatment plants which are currently being either operating or constructing. Exceptionally, PAC(Powdered Activated Carbon) process was evaluated with cost estimation from construction company. The capital cost per unit volume of ozone process was significantly decreased as the treatment capacity increased. The capital cost was in the order of GAC, ozone and GAC. The operation cost decreased in the order of PAC, GAC and ozone. The total cost considering present value shows that ozone process covers 84% of ozone and GAC process for $30,000m^3/d$ capacity while it covers less than 35% for over 140 thousands $m^3/d$ capacity. Comparing GAC only, and ozone/GAC process, ozone/GAC process is more cost effective for high capacity water treatment plant.

• Advances in environmental research
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• 제4권3호
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• pp.155-172
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• 2015

In this study, a complete set of recirculating cooling water system and the required instruments were built in a semi-industrial-scale and a 50 g/h ozone generation plant and a chlorine system were designed for cooling water treatment. Both chlorination and ozonation treatment methods were studied and the results were analyzed during two 45-days periods. The concentrations of ozone and chlorine in recirculating water were constant at 0.1 mg/lit and 0.6 mg/lit, respectively. In ozone treatment, by increasing the concentration cycle to 33%, the total water consumption decreased by 26% while 11.5% higher energy efficiency achieved thanks to a better elimination of bio-films. In case of Carbon Steel, the corrosion rate reached to 0.012 mm/yr and 0.025 mm/yr for the ozonation and chlorination processes, respectively. Furthermore, consumptions of the anti-corrosion and anti-sedimentation materials in the ozone cooling water treatment were reduced about 60% without using any oxidant and non-oxidant biocides. No significant changes in sediment load were seen in ozonation compared to chlorination. The Chemical Oxygen Demand of the blow-down in ozonation method decreased to one-sixth of that in the chlorination method. Moreover, the soluble iron and water turbidity in the ozonation method were reduced by 97.5% and 70%, respectively. Although no anaerobic bacteria were seen in the cooling water at the proper concentration range of ozone and chlorine, the aerobic bacteria in chlorine and ozone treatment methods were 900 and 200 CFU/ml, respectively. The results showed that the payback time for the ozone treatment is about 2.6 years.

• 한국대기환경학회지
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• 제34권5호
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• pp.708-726
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• 2018

In this study, we examined the contribution of nitrogen oxides and volatile organic compounds emitted from China and Japan to ozone concentrations over Gwangyang-bay, South Korea. We used a chemical transport model, Community Multi-scale Air Quality model, and its instrumented sensitivity tool, High-order Decoupled Direct Method. Intercontinental Chemical Transport Experiment-Phase B 2006 for East Asia and Clean Air Policy Support System 2007 emissions inventories for South Korea were used for the ozone simulation. During the study period, May 2007, the modeled maximum daily 8-hr average ozone concentration among seven air quality monitors in Gwangyang-bay was 68.8 ppb. The contribution of $NO_x$ emissions from China was 19.5 ppb (28%). The highest modeled ozone concentrations and Chinese contributions appeared when air parcels were originated from Shanghai area. The observed 8-hr average ozone concentrations in Gwangyang Bay exceeded the national ambient air quality standard (60 ppb) 203 times by daytime and 56 times by nighttime during the period. It was noticed that many exeedances happened when contribution of Chinese emissions to ozone concentrations over the area increased. Sensitivity analysis shows that a reduction in Chinese $NO_x$ and VOC emissions by 15% could lessen the total exceedance hours by 24%. This result indicates that high ozone concentrations over Gwangyang-bay are strongly enhanced by Chinese emissions.

• Journal of Microbiology and Biotechnology
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• 제28권8호
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• pp.1233-1246
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• 2018

Vibrio parahaemolyticus contamination causes serious foodborne illness and has become a global health problem. As a disinfectant, aqueous ozone can effectively kill a number of bacteria, viruses, parasites, and other microorganisms. In this study, three factors, namely, the aqueous ozone concentration, the exposure time, and the bacterial density, were analyzed by response surface methodology, and the aqueous ozone concentration was the most influential factor in the sterilization ratio. Under low aqueous ozone concentrations (less than 0.125 mg/l), the bacterial cell membranes remained intact, and the ozone was detoxified by intracellular antioxidant enzymes (e.g., superoxide dismutase and catalase). Under high aqueous ozone concentrations (more than 1 mg/l), cell membranes were damaged by the degree of peripheral electronegativity at the cell surface and the concentration of lactate dehydrogenase released into the extracellular space, and the ultrastructures of the cells were confirmed by transmission electron microscopy. Aqueous ozone penetrated the cells through leaking membranes, inactivated the enzymes, inhibited almost all the genes, and degraded the genetic materials of gDNA and total RNA, which eventually led to cell death.

• Journal of Preventive Medicine and Public Health
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• 제34권4호
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• pp.316-322
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• 2001

Objectives : To explore the possible effect of an interaction between summertime heat waves and ozone on cardiopulmonary mortality during the 1994 heat wave in Korea. Methods : The unusually hot summer of 1994 in Korea was defined as the heat wave in this study. We examined the associations of air pollutants with daily cardiopulmonary deaths between 1991-1995, considering the product term of the heat wave and each pollutant, weather and time trends. Results : During the heat wave, while temperatures were uniformly higher than those of other summers, the within-heat-wave difference in mortality paralleled that in the regional ozone levels. In terms of the influence of the heat wave, the results of ozone were different to those of total suspended particles (TSP) and sulfur dioxide $(SO_2)$. The ozone association (relative risk (RR) : 1.036; 95% confidence interval (CI) = 1.018-1.054) was observed only under heat wave conditions, while the TSP (RR : 1.006, 95% CI = 0.999-1.012) and the $SO_2$ (RR = 1.018, 95% CI : 1.011-1.024) associations were found under normal weather conditions (per interquartile increase of each pollutant; results of three pollutants model). The ozone association under heat wave was attributable to the statistical interaction between the heat wave and ozone. Conclusions : These results support the possibility of a biological synergy between the heat wave and ozone, one that is not evident between the heat wave and other major pollutants like particles or $SO_2$.

• The Plant Pathology Journal
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• 제15권4호
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• pp.210-216
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• 1999

TREGRO, a computer simulation model of individual tree growth, was applied to estimate ozone ($\textrm{O}_3$) effects on aspen(Populus tremuloides) growth under ambient and 1.7 times ambient $\textrm{O}_3$ of Seoul in 1996. The three highest $\textrm{O}_3$ (Kuui-dong, Ssangmun-dong, Sungsoo-dong) and the two lowest $\textrm{O}_3$ sites (Mapo-dong, Namgajwa-dong) were evaluated. The current ambient $\textrm{O}_3$ did not affect aspen growth compared to simulation without $\textrm{O}_3$. The only effect was 6.6 percent of total assimilated carbonloss at Ssangmun-dong where the level of $\textrm{O}_3$ was greatest among the 21 sites examined. Decrease as much as 50 percent of total carbon gain was calculated at 1.7 times ambient $\textrm{O}_3$ of the three highest sites. The carbon loss by $\textrm{O}_3$ came from biomass of tissues and total nonstructural cabron (TNC) such as starch and sugar. The most sensitive fraction was TNC and the next was root biomass. Foliage mass was not affected by $\textrm{O}_3$. Structural biomass loss was at best 1 to 3 percent at 1.7 times ambient $\textrm{O}_3$ at the two lowest sites. The daily carbon simulation was affected by $\textrm{O}_3$ mainly during Growth Period 4 (Jul. 21-Oct. 26). Correlations between site, dose, and the simulated responses of aspen (tissue biomass, TNC, respiration, and senescence) ranged from -0.703 to -0.973 depending on the plant responses. The ozone effects on poplar in Seoul are not severe currently, but are probably measurable at Ssangmun-dong. However, severe $\textrm{O}_3$ effects on biomass would occur if $\textrm{O}_3$ levels increase to 1.7 times ambient $\textrm{O}_3$ in Seoul. In addition, v could weaken the trees thus increasing susceptibility to pathogens or insects.

• 한국식품영양과학회지
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• 제35권8호
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• pp.1070-1075
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• 2006

김치 원부재료에 부착된 미생물을 김치제조 전부터 감균시키고 물성변화 없이 위생화된 재료로 김치를 제조하기 위한 기초실험으로 원부재료에 오존 및 감마선 처리를 하고 이들에 의한 미생물의 변화 및 화학적 변화를 측정하였다. 김치 원부재료에 부착된 총 균수는 약 10^6{\sim}10^7\;CFU/g$ 정도였으며 효모 및 곰팡이 수는 약 10^3{\sim}10^4\;CFU/g$ 정도로 나타났다. 그러나 원부재료에 오존을 처리한 경우, 대조군에 총균수에 비하여 약 1 log cycle 정도 또는 그 이상 감소하는 경향이었으며 처리량이 클수록 다소 낮은 균수를 보였다. 원부재료에 감마선을 조사한 경우에는 오존처리군에 비하여 감균효과가 큰 것으로 나타났으며, 조사선량이 증가할수록 균수의 감소는 큰 것으로 나타났다. 효모 및 곰팡이에서도 총균수와 비슷한 경향이었으며 5 kGy의 감마선 조사시에는 원부재료에 부착되었던 효모 및 곰팡이가 검출되지 않는 것으로 나타나 감마선 조사가 김치 원부재료내 미생물들을 효과적으로 감균시키는 것으로 나타났다. 또한 원부재료에 존재하는 성분(ascorbic acid, 총당 및 환원당)의 함량 변화에서는 오존 및 감마선 조사에 의한 변화는 대조군과 비교하여 크게 차이가 없는 것으로 나타났다.

• 한국산림과학회지
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• 제90권3호
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• pp.306-313
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• 2001

본 연구는 질소와 인의 영양상태에 따라서 오존에 노출시킨 조경수목의 생리적 반응과 오존에 대한 저항성을 이해하기 위하여 실시하였다. 1년생 소나무(Pinus densiflora S. et Z.) 묘목을 인공토양(버미큘라이트와 펄라이트)을 담은 플라스틱 화분에 심고, 6월초부터 변형된 Hoagland 용액을 이용하여 질소와 인을 조절하여 양묘하고, 7월 3일부터 8월 31일까지 open-top chamber(직경 2.5m, 높이 2.0m)내에서 8주간 1일 7시간씩(0.12ppm에서는 3시간씩) 오존농도를 자연상태에 유사하게 조절하여 노출시켰다. 오존대조구는 활성탄을 사용하여 오존농도를 0.02ppm 이하로 유지하였다. 8주 후에 부위별 생장량, 탄수화물 함량, 엽록소 함량, 순광합성속도를 측정하였다. 오존에 노출시킨 어떤 묘목에서도 가시적 피해를 관찰할 수 없었다. 오존대조구에서 질소와 인의 각각 혹은 동시 시비로 총건중량이 22%에서 95%까지 증가하여 시비효과를 확인하였다. 오존처리구에서도 시비효과는 비슷하게 관찰되었다. 오존처리는 오존대조구와 비교하여 건중량을 감소시키지 않았으나, S/R(Shoot/Root)용을 14.5% 증가시켰다. 잎의 설탕함량은 오존처리로 평균 23%가 증가한 반면에, 뿌리의 설탕함량은 질소와 인의 시비와 관계없이 오존처리로 평균 20% 감소하였다. 잎의 전분함량은 시비 혹은 오존에 의하여 크게 영향을 받지 않았으나, 뿌리의 전분함량은 오존처리로 41% 감소하여, 뿌리로 탄수화물의 이동이 감소함으로써 뿌리의 발달이 상대적으로 위축되었음을 입증하였다. 잎의 엽록소 함량은 질소시비에 의하여 70% 증가하였으나, 오존에 의해서 감소하지 않았다. 순광합성속도는 오존대조구에서 질소의 단독시비로 80% 증가하였으며, 인의 경우는 질소가 함께 시비될 때에만 광합성을 증가시켰다. 오존처리구의 순광합성속도는 오존대조구보다 평균 11.7% 적었는데, 특히 질소와 인이 동시에 시비되었을 때 오존대조구보다 22.3% 적었다. 반면 질소와 인이 시비되지 않은 경우에는 오존에 의해서 순광합성속도가 거의 영향을 받지 않았다. 위와 같은 질소와 인과 오존 간의 상호작용에서 다음과 같은 결론을 얻게 된다. 소나무 유묘는 단기간의 0.12ppm 오존 노출에서 가시적 피해를 입지 않았으며, 오존에 의하여 지상부의 생장이 감소하지 않지만 S/R 율은 증가하였다. 그러나 오존처리로 뿌리에서는 전분의 함량이 현저히 감소했을 뿐만 아니라, 순광합성속도도 큰 폭으로 감소하였으므로, 장기적으로 관찰하면 생장량이 감소하리라고 판단한다. 질소와 인의 시비에 의한 생장촉진효과는 오존으로 인하여 감소할 가능성이 있으나, 소나무에 시비하면 광합성을 촉진하고 탄수화물의 재분배를 통해서 오존피해를 복구하기 위한 에너지를 저축함으로써 저항성을 증진시킬 것으로 판단된다.