• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.442-450
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• 2014

Concern has grown over a presence of micropollutants in natural water since sulfonamide antibiotic substances such as sulfamethazine, sulfamethoxazole, sulfathiazole have been frequently detected in Nakdong River, Korea. The current work investigates the degradation of the three sulfonamide substances by using quantum chemistry calculations of density functional theory (DFT) and experimental measurement techniques of Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectrophotometer (UV-VIS). DFT calculations demonstrate that the lowest energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbitals (LUMO) lies in sulfanilamide functional group of sulfonamide, implying that the sulfanilamide functional group would be the most active site for ozone oxidation. Also, UV-VIS spectra and FT-IR analysis reveal that 260 nm band originated from sulfanilamide group was absent after ozone oxidation, indicating that a functional group of amine (N-H) was removed from sulfanilamide. Both theoretical and experimental observations agree well with each other, demonstrating the DFT calculation tool can be an alternative tool for the prediction of chemical reactions in purification treatment processes.

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.265-270
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• 2008

This study examined the effects of treating green tea leaves with ozonated water by evaluating pesticide residue levels and catechin content. The pesticide residue levels of tea leaves treated with carbendazim, captain, diazinon, fenthim, dichlorvos, and chlorpyrifos ranged from 43.2 to 48.2 ppm. For leaves treated by soaking or watering with tap water, or with 0.25 ppm of ozone water for 30 min. Pesticide residue levels were reduced by 24.0-30.2%, 30.3-33.6%, 52.4-70.5%, and 65.5-80.2%, respectively. No major differences in catechin content were observed in the leaves according to the soaking and rinsing treatments using ozonated or tap water.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.885-892
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• 2011

In this study, LCA(Life Cycle Assessment) on 'Saemangum CSO Project' was carried out to evaluate environmental impact which occurred during the construction and operation periods and the potential environmental impact reduction was analyzed by comparing production and reduction level of pollution loads. LCA was conducted out according to the procedure of ISO14040 which suggested Goal and Scope Definition, Life Cycle Inventory Analysis, Life Cycle Impact Assessment and Interpretation. In the Goal and Scope Definition, the functional unit was 1 m3 of CSO, the system boundary was construction and operation phases, and the operation period was 20 years. For the data collection and inventory analysis, input energies and materials from civil, architecture, mechanical and electric fields are collected from design sheet but the landscape architecture field is excepted. LCIA(Life Cycle Impact Assessment) was performed following the procedure of Eco-Labelling Type III under 6 categories which were resource depletion, eutrophication, global warming, ozone-layer destruction, and photochemical oxide formation. In the result of LCA, 83.4% of environmental impact occurred in the construction phase and 16.6% in the operation phase. Especially 78% of environmental impact occurred in civil works. The Global warming category showed the highest contribution level in the environmental impact categories. For the analysis on potential environmental impact reduction, the reduction and increased of environmental impact which occurred on construction and operation phases were compared. In the case of considering only the operation phase, the result of the comparison showed that 78% of environmental impact is reduced. On the other hand, when considering both the construction and operation phases, 50% of environmental impact is increase. Therefore, this study showed that eco-friendly material and construction method should be used for reduction of environmental impact during life cycle, and it is strongly necessary to develop technology and skills to reduce environmental impact such as renewable energies.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.464-472
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• 2020

We suggest a hydroponic cultivation system combined with a plasma generator to investigate the changes in the growth and functional substance content of lettuces during the cultivation period. Lettuce seedlings of uniform size were planted in semi-DFT after seeding for 3 weeks, and the plasma-activated water was intermittently operated for 1 hour at an 8 hours cycle for 4 weeks. Lettuces grew with or without plasma-activated water with the nutrient solution in hydroponics culture systems. Among the reactive oxygen species generated during plasma-activated water treatment, brown spots and necrosis appeared in the individuals closer to the plasma generating device due to O₃, and there was no significant difference in the growth parameters. While the rutin and total phenolic content of the lettuce shoot grown in the nutrient solution were higher than that of the plasma-activated water, epicatechin contents in plasma-activated water were significantly greater than the nutrient solution. However, in the roots, all kinds of secondary metabolites measured in this work, rutin, epicatechin, quercetin, and total phenolic contents, were significantly higher in the plasma-activated water than the control. These results were indicated that the growth of lettuce was decreased due to the reactive oxygen species such as ozone in the plasma-activated water, but the secondary metabolites in the root zone increased significantly. It has needed to use this technology for the cultivation of root vegetables with the modified plasma-activated water systems to increase secondary metabolite in the roots.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.240-246
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• 2005

Humic substances HS) from process waters at advanced water treatment plant consisted of GAC and Ozone/GAC processes were isolated and extracted by physicochemical fractionation methods to investigate their characteristics. They are characterized for their functionality, chemical composition, spectroscopic characteristics using FT-IR and $^1H$-NMR spectroscopy. Humic fraction gradually decreased from 36.3% to 24.2% from 0.45 to 0.30 mgC/L) through ozonation and carbon adsorption. The humic fraction was isolated into the phenolic and carboxylic groups using A-21 resin, and the concentration of phenolic groups gradually decreased from 38.4% to 23.5% (from 4.9 to $3.2\;{\mu}M/L$ as phenolic-OH) through ozonation and carbon adsorption. In the case of carboxylic groups, the concentration decreased from 61.6% to 43.3% (from 7.8 to $5.8\;{\mu}M/L$ as COOH) through the water treatment processes. On the other hand, concentrations of those roups decreased from 38.4% to 24.0% and 61.6% to 44.9% through carbon adsorption without ozonation, respectively. The structural changes of HS identified from FT-IR and $^1H$-NMR were consistent with the results from the isolation of functional groups in HS.