• 공업화학
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• 제16권4호
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• pp.570-575
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• 2005

하수방류수 살균 소독에 이용되는 UV 램프를 기존의 전극용보다 효율을 높이고 수명이 긴 무 전극 UV 램프를 제작하고 그 성능을 알아보았다. 우선 활성물질을 변화시키면서 제조한 램프의 UV 강도 및 온도의 변화를 실험 하였다. 그 결과 활성물질이 Hg/In의 무게비 95/5로 만든 램프를 250 min간 운전한 결과 UV 강도 $300{\mu}W/cm^2$ 및 온도 $200{\sim}250^{\circ}C$로 가장 안정적인 결과를 나타내었다. 그러나 무전극 램프를 장시간 발광시켰을 경우 램프의 온도가 상승하기 때문에 이를 방지하기 위해 실제 하수처리공정에 적용할 수 있는 냉각이 가능한 이중관 형태로 제작하여 UV 강도와 온도 변화특성을 알아보았다. 또한 제작된 무전극 UV lamp를 하수 방류수의 살균 소독을 위하여 대장균(E-coli.)으로 실험한 결과에서도 99.9% 이상의 살균효율을 보였다.

• 상하수도학회지
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• 제26권2호
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• pp.257-264
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• 2012

The concept of a non-contact type of UV disinfection system was introduced in this study. UV lamps and their quartz sleeves hang over the water surface and there is no interface between the sleeve and water. Obviously, there is no fouling. Based on optical laws and other UV distribution models, a detail mathematical model for a non-contact type UV disinfection system was developed in this study. Pathway length of UV light in a non-contact type photoreactor is longer than that in a submerged type photoreactor because the light is more refractive while passing through 3 interfaces of medium. But the pathway length passing through the water media is not significantly longer than that in a submerged type photoreactor so, the absorption of UV light by water is not significantly different from the other system. Due to the reflection effect, UV intensity is rapidly decreased as the horizontal distance from the light source is increased. The reflective attenuation in a non-contact type photoreactor is higher than that in a submerged type photoreactor. These mean that the short photoreactor is advantageous than the narrow-long photoreactor for the non-contact type photoreactor in an optical point of view.

• 전기학회논문지P
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• 제58권4호
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• pp.455-460
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• 2009

A number of factors combine to make ultraviolet radiation a superior means of water purification for ground water, rainwater harvesting systems and so on. Ultraviolet radiation is capable of destroying all types of bacteria. Additionally, ultraviolet radiation disinfects rapidly without the use of heat or chemical additives which may undesirably alter the composition of water. In a typical operation, water enters the inlet of a UV lamp and flows through the annular space between the quartz sleeve and the outside chamber wall. The irradiated water leaves through the outlet nozzle. Several design features are combined to determine the dosage delivered. The first is Wavelength output of the lamp, the Second is Length of the lamp - when the lamp is mounted parallel to the direction of water flow, the exposure time is proportional to the length of the lamp, the third is Design water flow rate - exposure time is inversely related to the linear flow rate, the forth is Diameter of the purification chamber - since the water itself absorbs UV energy, the delivered dosage diminishes logarithmically with the distance from the lamp. In this paper, It describe the how to design optimal UV disinfection device for ground water and rainwater. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method manufactured prototype applied to disinfection test and proved satisfied performance.

• 상하수도학회지
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• 제26권5호
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• pp.685-692
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• 2012

UV technology is widely used in water and wastewater treatment. Many researches have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on NOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics such as NOM. Pulsed UV treatment using UV flash lamp can be operated in the pulsed mode with much greater peak intensity. The pulse duration is typically in microseconds, whereas the interval between pulses is in the order of milliseconds. The high intensity of pulsed UV would mineralize NOM itself as well as change the characteristics of NOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of NOM. The objective of this study is to investigate the effect on NOM, chlorine residual, and chlorinated DBPs formation with pulsed UV treatment.

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.11-17
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• 2012

졸-겔 방법에 의하여 제조된 $TiO_2$와 $TiO_2-SiO_2$ 광촉매를 이용한 음용수 중의 대장균 살균과 엔도톡신 제거에 관한 연구를 수행하였다. 대장균 살균실험은 대장균이 포함된 물이 순환되는 annular-흐름식 광촉매 코팅 반응기에서 수행되었다. 대장균의 살균능은 $TiO_2$와 $TiO_2-SiO_2$ 광촉매의 아나타제 결정성피크의 세기와 비례하였다. UV-A 조사하에 $TiO_2$가 코팅된 반응기에서 2시간 내에 대장균을 100% 살균시킬 수 있었으며, 대장균 사멸시 생성되는 독성물질인 엔도톡신이 존재하지 않았다. 그러나 UV-C 조사하에서는 30분 이내에 대장균을 100% 살균할 수 있었으나 엔도톡신이 완전히 제게되지 않았다. 따라서 광촉매와 UV-A 조사가 음용수 살균에 유용함을 알 수 있었다.

• 상하수도학회지
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• 제20권5호
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• pp.755-761
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• 2006

Recently, there is growing interest in ultraviolet (UV) irradiation as a disinfection technic in drinking water production due to its effectiveness to inactivate microorganisms such as Crytosporidium parvum without forming disinfection byproducts. However, UV disinfection is known for its drawback such as photoreactivation. Despite many works concerning the photoreactivation, most of works were focused on indicator or non pathogenic microorganisms. The objective of this study is to examine the photoreactivation of Pseudomonas aeruginosa which is an opportunistic pathogen as UV radiation by LP and MP UV lamp was applied. The result showed that P. aeruginosa had high photo repair efficiency regardless of the type of UV irradiation. Both of the effective log repair values of LP and MP UV irradiation were found approximately 2.6 log. In addition, photo repaired P. aeruginosa was not significantly different in forming biofilm in comparison with non treated P. aeruginosa.

• 대한환경공학회지
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• 제29권9호
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• pp.1020-1026
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• 2007

전 세계적으로 병원성 미생물에 의한 오염과 감염 및 발병의 사례가 급증함에 따라 병원성 미생물을 효율적으로 제어하는 기술에 대한 관심이 매우 증가하고 있다. 병원성 미생물을 환경에서 제어하는 연구는 대다수 수처리 공정과 같이 물에서 이루어지는 소독과 관련되어 진행되어 왔고, 표면에서의 소독에 관련된 연구는 매우 부족하였다. 본 연구는 UV 소독 방법을 표면에 분포된 미생물의 불활성화에 대해서 적용하여 살펴보았고, 소독 모델을 통해서 정량화하였다. 특히, 생물테러용 무기로 잘알려진 탄저균(Bacillus anthracis)의 지표 미생물인 바실러스 포자(Bacillus subtilis spore)에 대해서 UV를 이용한 표면 소독시 매우 빠른 불활성화를 볼 수 있었으며, 2 log(99%) 불활성화를 위한 IT 값은 14.5 $mJ/cm^2$으로 나타났다. UV에 의한 미생물 불활성화는 화학적 소독제의 경우와 달리 온도에 의한 영향은 나타나지 않았으나, 표면 거칠기(surface roughness)에 의한 뚜렷한 tailing off 현상이 나타났다.

• 한국환경과학회지
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• 제19권7호
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• pp.889-900
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• 2010

The experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV process were mathematically described as a function of parameters power ($X_1$), NaCl dosage ($X_2$), initial pH ($X_3$) and disinfection time ($X_4$) being modeled by use of the Box-Behnken technique. The application of RSM using the Box-Behnken technique yielded the following regression equation, which is an empirical relationship between the residual E. coli number and test variables in actual variables: Ln (CFU) = 23.57 - 0.87 power - 1.87 NaCl dosage - 2.13 pH - 2.84 time - 0.09 power time - 0.07 NaCl dosage pH + 0.14 pH time + 0.03 $power^2$ + 0.47 NaCl $dosage^2$ + 0.20 $pH^2$+ 0.33 $time^2$. The model predictions agreed well with the experimentally observed result ($R^2$ = 0.9987). Graphical response surface and contour plots were used to locate the optimum point. The estimated ridge of maximum response and optimal conditions for the E. coli disinfection using canonical analysis was Ln 1.06 CFU (power, 15.40 W; NaCl dosage, 1.95 g/L, pH, 5.94 and time, 4.67 min). To confirm this optimum condition, the obtained number of the residual E. coli after three additional experiments were Ln 1.05, 1.10 and Ln 1.12. These values were within range of 0.62 (95% PI low)~1.50 (95% PI high), which indicated that conforming the reproducibility of the model.

• 대한환경공학회지
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• 제33권3호
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• pp.149-156
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• 2011

수중에서 E. coli 소독을 위한 전기-UV-초음파 복합 공정에 대해 실험계획법과 반응표면분석법(RSM)을 적용하였다. 2차반응표면 모형식을 추정할 수 있는 Box-Behnken법을 이용하여 전기-UV-초음파 복합 공정의 소독 반응에서 전기분해($X_1$), UV ($X_2$), 및 초음파 공정($X_3$)의 전력을 독립변수로 선정하여 수학적으로 모형화하였다. 소독 후 잔류 E. coli 수와 독립변수 사이의 실험에서 독립변수에 대해 다음의 모형식이 얻어졌다. 잔류 E. coli number (Ln CFU) = 23.69 - 3.75 Electrolysis - 0.67 UV - 0.26 Ultrasonic - 0.16 Electrolysis UV + 0.05 Electrolysis Ultrasonic + 0.27 $Electrolysis^2$ + 0.14 $UV^2$ - 0.01 $Ultrasonic^2$). 예측된 모형식은 실험 자료와 잘 일치하였다($R^2$ = 0.983). 2차원 등고선도와 3차원 반응표면도가 잔류 E. coli 수에 대한 최적 범위를 구하기 위하여 사용되었다. Design-Expert 소프트웨어의 '수치 최적화'를 이용하여 잔류 E. coli 수에 대한 최적 값을 찾은 결과 1.47 Ln CFU/L이었고, 최적 조건은 전기분해 6.94 W, UV 6.72 W 및 초음파 공정 14.23 W로 나타났다. 본 연구는 반응표면분석법이 복합 소독 공정에서 잔류 E. coli 수를 최소화하고 운전 조건을 최적화하기 위한 적절한 방법 중의 하나라는 것을 보여주었다.

• Journal of Microbiology and Biotechnology
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• 제33권1호
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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.