• Journal of Korean Society of Water and Wastewater
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• v.22 no.4
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• pp.421-427
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• 2008

UV disinfection is widely used in water treatment facilities and wastewater treatment plant because of its effectiveness to removal of pathogen and Giardia which is resistant to traditional chemical disinfection. As a design and performance tool of UV disinfection system, 3 dimensional UV intensity models were composed and simulated to compare each other and to find affecting factors in this study. Reflection, refraction and absorption are important parameters in UV intensity model and MPSS and MSSS model can reflect these parameters while LSI model can not. Absorption is the most important parameters among the reflection, refraction, absorption and shadowing so, this should not be neglect. Based on this simulation, shadowing effect is negligible when the number of installed lamp is a few but, this effect can not be neglectable when the number of installed lamp is quite a few. The errors according to shadowing effect is increased as the number of lamp installed increased.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.2
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• pp.139-145
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• 2016

Disinfection of microorganisms using UV light is widely used in the field of water supply and wastewater treatment plant, In spite of high germicidal effect and relatively clean by-product, UV disinfection has fundamental defeat that is accumulation of fouling materials at the interface of water and lamp sleeve. Non-contact type of UV photoreactor which can avoid this fouling generation was developed and the experimental performance evaluation of the system was carried out in this study. Log inactivation rate of E. coli was selected as a disinfection index. The concentration of E. coli of second clarifier effluent was $8.2{\times}10^1-8.2{\times}10^3$ colony per mL and was well inactivated by the non-contact type of UV photoreactor. Under the UV intensity condition of $2.1-2.5mW/cm^2$, E. coli removal rate was observed in the range of 54 - 95% when the HRT was increased from 10 to 52 seconds. Experimental results showed that log inactivation of E. coli was proportional to UV dosage and $200mJ/cm^2$ of UV dose is expected for the 2.0 log inactivation of E. coli from the second clarifier effluent. Between the two parameters of UV intensity and contact time which are consist of UV dose, UV intensity was 4 times more effective than contact time.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.952-958
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• 2009

The International Maritime Organization (IMO) has adopted the ballast water management convention at a diplomatic conference in early 2004 that all ships should be equipped with a treatment system from 2010 gradually. In this paper, the disinfection characteristic of ultra-violet (UV) rays was studied and a ballast water treatment system (BWTS) which can treat $50m^3$/h sea water was manufactured. The system consists of a disinfection chamber with six 3.5 kW UV lamps which are operated by magnetic ballasts, a programmable logic controller (PLC) and set of pipe lines. The biological disinfection efficacy of the prototype BWTS was evaluated following the IMO rules using zooplankton such as Artemia and Rotifer species for the size over $50{\mu}m$, and phytoplankton such as Tetraselmis and Thalassiosira species for the size between 10 to $50{\mu}m$. From the experimental results, the disinfection efficacy was 99.99 % that meets the IMO requirement. However, more studies on an energy saving system are needed because the consumption power of the prototype system is as high as over 21 kWh for $50m^3$/h.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.11-17
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• 2012

Disinfection of Escherichia coli (E. coli) in drinking water was investigated by using $TiO_2$ and $TiO_2-SiO_2$ based photocatalyst prepared by sol-gel method. The disinfection test was carried out in an annular flow reactor with circulating sterile water containing the photocatalysts powder under UV-A irradiation. The disinfection activity was proportional to the anatase`s intensity of crystalline peak of the $TiO_2$ photocatalysts. 100% disinfection of E.coli without endotoxin was achieved with $TiO_2$ coated photocatalytic system under UV-A irradiation within 2 h. However, toxic endotoxine was exist in the disinfection of E.colithe under UV-C irradiation even though 100% disinfection of E.colithe within 30 min, which suggest that $TiO_2$ coated photocatalytic system with UV-A is useful tool for the disinfection of E.coli in drinking water.

• Journal of fish pathology
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• v.28 no.3
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• pp.125-131
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• 2015

This study was performed to determine the disinfection efficacy of influent seawater by application of mechanical filtration and UV disinfection system (MFUVDS) in decreasing disease outbreak of juvenile olive flounder (Paralichthys olivaceus). Bacterial disinfection rate of influent seawater following the MFUVDS application was 99.27%. Mortalities of the juvenile reared for 4 months were 20~30% lower than those of the control (25.8%~34.9%).

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.175-182
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• 2022

This work presents a simulation model for a specific UV disinfection system (UVDS) powered by a Photovoltaic System. The global UVDS also includes the electronic converters, Electronic Ballast, UV Lamp and Motor Pump. The equations that model the physical components' behaviour are connected to obtain a dynamic global model. The latter is converted in a Simulink/Matlab model, which allows to carry out simulation series concerning the entire UVDS. The physical parameters: the irradiation G and the temperature T, are considered as inputs. series of measurements carried out in order to show how these parameters affect the current, the voltage of the PVs and especially the value of the current of the UV lamp, on the other hand a study on the behavior and the evolution of the parameters of the motor pump such as the armature current, motor torque, speed of rotation and the water flow. The purpose of all this is to realize how important are the two parameters concerning the lamp current and the water flow because they are two very important factors to keep an adequate water quality.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.61-72
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• 2014

Study on effluent organic matter (EfOM) characteristic and removal efficiency is required, because EfOM is important in regard to the stability of effluents reuse, quality issues of artificial recharge and water conservation of aqueous system. UV technology is widely used in wastewater treatment. Many reports have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on EfOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics. The high intensity of pulsed UV would mineralize EfOM itself as well as change the characteristics of EfOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of EfOM. The objective of this study is to investigate the effect on EfOM, chlorine residual, and chlorinated DBPs formation with low pressure and pulsed UV treatment. The removal of organic matter through low pressure UV treatment is insignificant effect. Pulsed UV treatment effectively removes/transforms EfOM. As a result, the chlorine consumption is changed and chlorine DBPs formation is decreased. However, excessive UV treatment caused problems of increasing chlorine consumption and generating unknown by-products.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.106-113
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• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• Environmental Engineering Research
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• v.21 no.4
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• pp.350-354
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• 2016

There is an urgent need to identify more reliable indicator systems for human pathogenic viruses in water reuse practice. In this study, we determined the response of different bacteriophages representing various bacteriophage groups to different ultraviolet (UV) technologies in real wastewater in order to identify more reliable bacteriophage indicator systems for UV disinfection in wastewater. Bacteriophage ${\varphi}X174$ PRD1, and MS2 in two different real wastewaters were irradiated with several doses of both low pressure (LP) and medium pressure (MP) UV irradiation through bench-scale UV collimated apparatus. The inactivation rate of ${\varphi}X174$ by both LP and MP UV was rapid and reached ${\sim}4{\log}_{10}$ within a UV dose of $20mJ/cm^2$. However, the inactivation rates of bacteriophage PRD1 and MS2 were much slower than the one for ${\varphi}X174$ and only ${\sim}1{\log}_{10}$ inactivation was achieved by the same UV dose of $20mJ/cm^2$. Overall, the results of this study suggest that bacteriophage MS2 could be a reliable indicator for human pathogenic viruses for both LP and MP UV disinfection in wastewater treatment processes and water reuse practice.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1141-1146
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• 2010

Isolated the heterotrophic aerobic bacteria in sandfiltered water on NA and TSBA solid medium, selected 8 dominant species and identified by Sherlock System. Each samples are irradiated 0, 5, 16, 40 and $60\;mJ/cm^2$ using on CBD (Collimated Beam Device) Medium Pressure UV lamp after these identified bacterium did liquid culture how to make $10^6{\sim}10^7\;cells/mL$ suspended in dilution water. Then cultured bacteria are estimated inactivation rate on plate media. Identified Gram positive group are Bacillus Subtilus, Bacillus megaterium, Rhodococcus erythropolis and Microbacterium laevaniformans; Gram negative group are Pseudomonas vesicularis, Pseudomonas pseudoflava, Alcaligenes paradoxus and Zooglea ramigera. These isolation of bacterium are more stronger reference strain and high resistance of MP UV irradiation, Besides Gram negative bacterium are more sensitive Gram positive bacterium on MP UV dose. Now we are estimating to $60{\sim}100\;mJ/cm^2$ MP UV dose for efficient disinfection in water treatment plant.