• Journal of Environmental Science International
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• v.19 no.3
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• pp.261-267
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• 2010

The variation of assimilable organic carbon(AOC) concentration at each condition of ozonation was investigated using a model water and drinking water resource. AOC concentration of model raw water and drinking water resource tended to increase at low ozone dose. The maximum AOC concentration was detected when the residual ozone begin to be measured. Also, the AOC concentration increase at pH 8 compared to both pH 6 and 7 while that for pH 9 decreased rapidly. The removal characteristics of trihalomethane formation potential(THMFP) by ozonation was also investigated. Unlike the trend of AOC, the THMFP concentration never increased by ozonation but decreased even at low ozone dosage. From these results, the ozone dosage would be effective to simultaneously decrease both AOC and THMFP.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.142-147
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• 2006

The present study describes carbohydrate metabolism, macro-element utilization and antioxidant defenses in response to an ozone dose (100 ppb, 8d) in two rice varieties. Tolerant (cv. Jinpumbyeo) and sensitive (cv. Chucheongbyeo) varieties of rice were grown in growth chamber for 30 days after sowing. Concentrations of chloroplast pigments and non-structural carbohydrates as well as activity of antioxidant enzymes were determined to evaluate the resistance against ozone stress. Ozone caused the decrease in chlorophyll a and carotenoid contents, and also resulted in faster decomposition of non-structural carbohydrate in leaf blade and leaf sheath. The contents of nitrogen and potassium in leaves were visibly decreased in cv. Chucheongbyeo with an increase in ozone exposure, but not in cv. Jinpumbyeo. Enzymatic antioxidants against ROS in both varieties responded in the order of POD, SOD and CAT, and their capacity was stronger in cv. Jinpumbyeo.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.8
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• pp.311-315
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• 2016

The efficiency of manure treatment was investigated in terms of the pH, BOD, COD, SS, T-N and TP with a variation in the injection amount of PAC, polymer and ozone. The wastewater flow rate to the AOF is of $7.4m^3/hr$ with a reaction time of 30 minutes. The amount of PAC and polymer changed by 30, 35, 40 ml/min, and 30, 40, 50 ml/min, respectively. The amount of ozone injected varied from 110, 125, and $150kg-O_3/hr$. The optimum manure treatment performance was found for a PAC of 35 ml/min for the COD and SS, with polymer of 30 ml/min, and ozone injection of $150kg-O^3/hr$. A substantially optimum dose for each PAC, polymer, and ozone was also found to exist.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.29-38
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• 2007

Recently, the tropospheric ozone has gained a global attention for its adverse effect on vegetation as well as its contribution to the global warming. Although a number of studies have been carried out for the urban ozone, the effect of ozone on vegetation is still largely unknown in Korea. The present work aimed at performing the first evaluation of forest damage by ozone using the national air monitoring data from the year 2000 to the year 2005. Moreover, it also explored the relevance of adverse effect of ozone to the recent events on leaf chlorosis of black locust, Robinia pseudo-acacia, leading to early foliage widely observed in Korea since 2001. In the nineties, forest damages caused by ozone such as leaf chlorosis occurred in Europe and North America and led to invoke comprehensive field and laboratory studies. As a result, AOT40, implying the accumulated dose over a threshold 40 ppb, was developed to assess the forest damage by ozone. 19 air monitoring stations were selected across Korea to calculate AOT40 from the year 2000 to the year 2005. The calculated AOT40 generally increased during April and May and reached the maximum after May. The increase of AOT40 diminished substantially from the mid-June as the rainy season started. The calculated AOT40 in the nine rural sites from the year 2002 to th ε year 2005 ranged from 6.8 to 29.4 ppm-hr. And all the AOT40 at th ε year 2005 exceeded the critical value of 10 ppm-hr for forest damage. Morevoer the calculated AOT40 of Korea appeared higher than the AOT40 of Europe in the year 2004/2005 and comparable to the AOT40 of China in the year 2000. Despite the high levels of the calculated AOT40 since the year 2001 and the consistency of time of seasons between high AOT40 values and occurrence of chlorosis of black locust, further studies are required to conclude that the chlorosis of black locust occurred from the year 2001 to the year 2005 were resulted from a damage by ozone.

• 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.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.800-808
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• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• Journal of environmental and Sanitary engineering
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• v.12 no.2
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• pp.43-49
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• 1997

Iron and manganese problems in ground water affect far more water systems than almost any other water quality concern. The purpose of this study is to find the optimum condition of ozonation for the removal of dissolved iron, manganese and other organics in the polluted ground water. We proposed 4mg/l, 8mg/l as optimum ozone dose for the removal of $Fe^{2+},{\;}Mn^{2+}$, respectively. The removal efficiencies of $COD_{Mn}$ and $COD_{Cr}$ in ozone dose of 2mg/l - 6mg/l were about 40-50%. The removal efficiency of $NH_{3}-N$ was about 30-40% at pH8.5. In conclusion, it needs further systematic study and research concerned to treatability of $Fe^{2+},{\;}Mn^{2+}$ and biodegradability of organic compounds using Ozonation followed by biological filtration process in ground water treatment train.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.311-316
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• 2014

Effects of operating parameters such as activated carbon dose and pH on the phenol oxidation in ozone-activated carbon hybrid process were investigated through a kinetic study. Activated carbon enhanced the self-decomposition of ozone, generating $OH{\cdot}$, thus promoting phenol degradation. The pseudo-first order rate constants of phenol degradation increased and half-life of phenol decreased with activated carbon dose. The increase of pH enhanced $OH{\cdot}$ generation through chain reactions initiated by $OH^-$, therefore increasing the phenol degradation rate. TOC removal efficiency increased about 3.2 times by adding activated carbon in ozonation process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.688-696
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• 2018

This study investigated the effects of ozone-produced oxidants (OPO) on the growth, hematology, and histology of olive flounder Paralichthys olivaceus (average weight 500 g), raised in an ozonated semi-recirculating aquaculture system. The system was ozonated to maintained OPO concentrations of 0.004 (Control), 0.014 (OPO15), and 0.025 (OPO25) mg $Cl_2/L$ in culture tanksfor 26 days. The specific growth rate, feed conversion ratio, and survival rate did not significantly differ among the groups (P>0.05), while the daily feeding rate decreased OPO-dose-dependently (P<0.05). OPO appeared to affect the gill, hepatopancreas, and kidney tissues of fish from ozonated tanks. Hematologically, OPO affected some blood indices. The levels of chloride, glucose, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were significantly increased in the ozonated groups, while the total cholesterol and cortisol decreased dose-dependently. These results imply that long-term exposure of olive flounder to an OPO concentration ${\geq}0.014mg\;Cl_2/L$ might result in damage to the gill, hepatopancreas, and kidney tissues and cause physiological stress, albeit with no apparent short-term effects on growth or survival.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.2
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• pp.97-107
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• 1995

Today a conventional water treatment system has many problems. The ozone/GAC process, sometimes termed Biological Activated Carbon(BAC), appeared to be effective for the removal of soluble organic matters in the drinking water. The water quality of Nak-dong river in Pusan, generally shows BDOC 30-40% and NBDOC 60-70%. The pilot plant installed at the Duk-san water works that was been largest treatability(1,650,000ton/day) in Pusan. A experimental water in the pilot plant made use of the water after sand-filteration. Following results are drawn from this study. Initial adsorption velocity($DOC/DOC_o/T$) in the pure adsorption of GAG had a 0.0225, it's velocity changed to 0.006 after ozone added and the optimum ozone dose ranged of $1.4-2.0mgO_3/L$. A experimental water in the pilot plant composed with humic material(78%). Humic material composed with humic acid(20%) and fulvic acid(56%), and it's rate changed to 18 and 50% respectively after ozone added. DOC constantly decreased in the EBCTs and removal efficieny in the 15min of EBCT was 45-50%. It showed the largest removal rate of BDOC in the EBCT 5 and among the season, characteristics of removal varied. The HPC distributed over $10^6-10^7CFU/cm^3$ in the bed depth and among the season, distribution of HPC were differential.