• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.579-585
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• 2003

Recently the utilization of the ozone dissolved de-ionized water(DI-O3 water) in semiconductor wet cleaning process to replace the conventional RCA methods has been studied. In this paper, we propose the water-electrode type ozone generator which has the ozone gas characteristics of the high concentration and high purity to produce the high concentration DI-O3 water for the silicon wafer surface cleaning process. The ozone generator has the dual dielectric tube structure of silent discharge type and the water is both used to electrode and cooling water. We investigate the performance of the proposed ozone generator which has the design goal of the concentration of 7[wt%] and ozone generation quantity of 6[g/hr] at flow rate of 1[$\ell$/min). The experiment results show that the water electrode type ozone generator has the characteristics of 8.48[wt%] of concentration, 8.08[g/hr] of generation quantity and 76.2[g/kWh] of yield and it's possible to use the proposed ozone generator for the DI-O3 water cleaning process of silicon wafer surface.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.124-127
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• 2003

Laboratory scale experiments on in-situ ozonation were carried out to delineate the effects of liquid phases, such as soil water and nonaqeous phase liquid (NAPL) on the transport of gaseous ozone in unsaturated soil. Soil water enhanced the transport of ozone due to water film effect, which prevent direct reaction between soil particles and gaseous ozone, and increased water content reduced the breakthrough time of ozone because of increased average linear velocity of ozone and decreased air-water interface area. Diesel fuel as NAPL also played a similar role with water film, so the breakthrough time of ozone in diesel-contaminated soil was significantly reduced compared with uncontaminated soil. However, ozone breakthrough time was retarded with increased diesel concentration, because of high reactivity of diesel fuel with ozone. In multiphase liquid system of unsaturated soil, the ozone transport was mainly Influenced by nonwetting fluid, diesel fuel in this study.

• Journal of Environmental Science International
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• v.22 no.4
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• pp.453-461
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• 2013

This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 mg/L, THMFP> 70 ${\mu}g/L$, Chl-a> 30 $mg/m^3$or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.905-913
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• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2041-2043
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• 2000

Ozone is widely used to sterilize food and tap water because ozone is a strong oxidizer. To date, it has been difficult to dissolve a high concentration of ozone gas in water because the large size of the bubbles limits the contact area between the ozone gas and liquid water. The measurements of dissolved ozone can be used to control water quality and ozone dosage. Therefore the dissolved ozone measurement of most interest is that of residual ozone at the discharge point of a particular treatment chamber.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1137-1143
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• 2006

In this study we investigated the removal characteristics of NOM and bromate formation characteristics in SOMT reactor. The system was recently developed as a novel ozone reactor and installed in SJ pilot plant. DOC values were decreased within 3% after treatment of 0.5~2.0 mg/L ozone dosage in SOMT reactor while the $UV_{254}$ value was 69% decreased at 2.0 mg/L ozone dosage. The composition of NOM was analysed by LC-OCD (Organic Cabon Detector) after ozone treatment in SOMT reactor to elucidate the variation of NOM character. Polysaccharide (more than 20,000 g/mol) fraction of NOM was decomposed while building blocks (350~500 g/mol) and neutral (less than 350 g/mol) fraction increased. Spiked bromide reacted with 0.5~2.0 mg/L ozone dosage in the SOMT reactor. The bromate formation was proportional to the ozone dosage ($R^2=0.978$) but not proportional to reaction time. The maximum concentration of formated bromate was not exceeded to 10% of spiked bromide concentration.

• 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.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.763-768
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• 2009

Ozone is a strong oxidant and a powerful disinfectant. In general, it has been used in drinking water treatment during last 100years. Ozone dissolution features are defined by the two categories of ozone contactors, bubble-diffuser and sidestream ozone contactor. Currently, sidestream-injection systems are gaining in popularity but operating cost might be slightly higher. Sidestream ozone system dissolve ozone into a sidestream flow via an injection setup or in the main process flow stream in some sidestream arrangements. The sidestream flow is subsequently mixed with the main process flow stream, which is directed to a reation tank or pipeline for oxidation and disinfection reactions. The purpose of this study is to suggest optimal operating pressure, to figure out the static-mixer effect and to understand the microbubble characteristics of ozone to improve dissolution efficiency.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.7-13
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• 2005

With the appearance of pathogenic microorganisms, which were resistant to free chlorine, the significant attention to the necessity of powerful alternative disinfection methods such as ozone, chlorine dioxide, LTV irradiation to inactivating pathogens has been increased in water treatment. Among these alternative disinfection methods, ozone is well known as strong biocidal method and the usage of ozone is also increasing in Korea. However, in Korea, there has been no report on the quantitative study of Cryptosporidium parvum with ozone and its evaluation in advanced drinking water treatments. This study reports on the methodology for predicting the ozone inactivation of Cryptosporidium parvum by ozone disinfection in advanced drinking water treatment. The method is based on the fact that a specific inactivation level of microorganisms is achieved at a unique value of ozone exposures, independent of ozone dose and type of water, and quantitatively described by a delayed Chick-Watson model. The required values ${\bar{C}}T$ for 2 log inactivation of Cryptosporidium parvum was $6.0mg/L{\cdot}min$ and $15.5mg/L{\cdot}min$ at $20^{\circ}C$ and $5^{\circ}C$, respectively. From this obtained Cryptosporidium parvum inactivation curves and calculated ${\bar{C}}T$ values of advanced drinking water treatment water in Korea with FIA (Flow injection alaysis), we can predict that water treatment plant can achieve a 1.1~1.8 log inactivation and 0~0.4 log inactivation at $20^{\circ}C$ and $5^{\circ}C$, respectively. This methodology will be useful for drinking water treatment plants which intend to evaluate the disinfection efficiencies of their ozonation process without full scale test and direct experiments with Cryptosporidium parvum.