• 전기학회논문지P
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• 제59권4호
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• pp.411-416
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• 2010

Interest in application of ultraviolet light technology for primary disinfection of potable water in drinking water treatment plants has increased significantly in recent years. The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics(CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. In this paper, It describe the how to design optimal UV disinfection device for ground water, BWT and rainwater. Spring shape instrument silver coated located in inner side of disinfection chamber. It make lead the active flowing movement target water and maximize disinfection performance. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method, performed simulation and proved satisfied performance.

• 대한환경공학회지
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• 제30권8호
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• pp.755-759
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• 2008

모노클로라민과 디메틸아민 농도와 관련 있는 염소, 질소, 탄소 비율에 따라서 소독부산물인 NDMA 생성을 여러 조건에서 조사하였다. 디메틸아민/모노클로라민 비율이 1에 근접 할 경우에 NDMA 생성이 높게 나타났으며 아주 작거나 너무 클 경우 생성은 급속하게 감소하였다. 염소/질소 비율이 증가함에 따라 NDMA 생성도 증가하는 것으로 조사되어 염소 성분이 생성에 중요한 지표가 됨을 알 수 있었다. 접촉시간에 따른 NDMA 생성 영향을 조사한 결과, 본 연구에서는 72시간에서 급속하게 증가하는 것을 볼 수 있다. 기존연구에서와 같이 본 연구에서도 pH는 NDMA 생성에 중요한 영향을 주는 요소로 조사되었다.

• 상하수도학회지
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• 제28권3호
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• pp.287-297
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• 2014

It is important to predict chlorine decay with different water purification processes and distribution pipeline materials, especially because chlorine decay is in direct relationship with the stability of water quality. The degree of chlorine decay may affect the water quality at the end of the pipeline: it may produce disinfection by-products or cause unpleasant odor and taste. Sand filtrate and dual media filtrate were used as influents in this study, and cast iron (CI), polyvinyl chloride (PVC), and stainless steel (SS) were used as pipeline materials. The results were analyzed via chlorine decay models by comparing the experimental and model parameters. The models were then used to estimate rechlorination time and chlorine decay time. The results indicated that water quality (e.g. organic matter and alkalinity) and pipeline materials were important factors influencing bulk decay and sand filtrate exhibited greater chlorine decay than dual media filtrate. The two-component second-order model was more applicable than the first decay model, and it enabled the estimation of chlorine decay time. These results are expected to provide the basis for modeling chlorine decay of different water purification processes and pipeline materials.

• 한국환경보건학회지
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• 제23권2호
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• pp.106-114
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• 1997

When surfactants meet chlorine bleaches not only in the washing drums but also through the whole path from the stream to the river, it is not difficult to expect that they produce the harmful substances like DBPs. Furthermore considering wastewater that is contaminated by surfactants is used to discharge into drinking water sources via sewer system, it also can be imagined that residual surfactants would contribute to the some extent of DBPs' formation during chlorine disinfection in water treatment plants. Although the main behavior observed was the formation of chloroform during the reaction of LAS with free chlorine, the other manifest behaviors like the trends of pH, MBAS, free chlorine, the mole concentration of benzene ring and etc. were also investigated.

• 상하수도학회지
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• 제20권5호
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• pp.701-707
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• 2006

Disinfectant residual should be maintained to achieve biological stability during distribution of treated water. The wide distribution of retention times associated with storage and transport of water in a network and the reactivity of disinfectants make it difficult to maintain adequate residuals at critical locations. Rechlorination at some intermediate locations may reduce the total disinfectant dose while keeping residuals within specified limits throughout the water distribution system. In order to select the adequate location of rechlorination for achieving to maintain of residual chlorine throughout the distribution system, EPANET was used in this study. EPANET was well predicted chlorine transport and residual loss in the distribution system. Location of rechlorination was selected to maintain 0.4mg/L of residual chlorine throughout a water distribution system by field investigation and model simulation. The quantity of chlorine may reduced 36.7% and provided smooth residual between 0.42 and 0.60mg/L, when rechlorination would be used continuously at strategic location within the distribution system.

• Corrosion Science and Technology
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• 제17권1호
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• pp.12-19
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• 2018

Langelier Index (LI) is used as a tap water corrosiveness index. Residual chlorine in tap water induces corrosion inside water pipes. This study takes a deeper look into the effect of residual chlorine in water pipes. Comparison between tap waters of Y and K water treatment plant (WTP) shows that the LI index of K WTP is lower than that of Y. However, the corrosion rate of Y WTP is higher than that of K WTP. This means that the higher the concentration of residual chlorine in tap water, the higher the corrosion rate of pipe materials. When calcium hydroxide was added to tap water, the corrosiveness index was improved and thus the corrosion rate reduced. It is possible to increase the disinfection efficiency by increasing the duration of residual chlorine and suppressing the rust generation of water pipes and to supply minerals. A guideline for corrosion control with residual chlorine should be set up. The effects of residual chlorine should be included in the corrosiveness index of tap water.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권2호
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• pp.71-78
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• 2000

The chlorination of municipal drinking water supplies leads to the formation of so-called disinfection by-products(DBPs), many of which have been reported to cause harmful health effects based on animal studies. This study was conducted: 1) to observe seasonal changes in the major DBPs at four sampling sites on a drinking water distribution system located in Chunchon, Kangwon Do; and 2) to examine the effects of major water quality parameters on the formation of DBPs. During the field sampling, the water temperature, pH, and total and free chlorine residuals were all measured. The water samples were then analyzed for total organic carbon(TOC) and eight disinfection by-products in the laboratory. Chloroform, dichloroacetic acid, and trichloroacetic acid were the major constituents of the measured DBPs. The concentrations of the total DBPs were highest in fall, particularly in October, and lowest in summer. The concentrations of the total DBPs increased with increasing TOC concentrations. Multiple regression analyses showed that the concentrations of chloroform, bromodichloromethane, and chloral hydrate were linearly correlated with the pH. Other water parameters were not included in the regression equations. Accordingly, these results suggest that TOC and pH are both important factors in the formation of DBPs.

• 한국수자원학회논문집
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• 제55권spc1호
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• pp.1197-1210
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• 2022

최근 국내에서는 관로 노후화 및 다양한 수질사고 발생으로 인해 상수도 분야에 대한 관심이 급증함에 따라, 상수도 서비스에 대한 이용자들의 수질민원 또한 증가하고 있다. 수질민원의 경우 실제 수질오염뿐만 아니라 소독을 위한 잔류염소농도에 대한 불편을 포함하고 있으며, 따라서 사용자에게 공급되는 잔류염소농도를 균등하게 유지하기 위해 재염소 처리와 같은 다양한 노력이 시도되고 있다. 본 연구에서는 상수관망 내 잔류염소농도 모의를 위해 적용 대상지역의 수질반응계수를 추정하였으며, 수질기준을 만족시키는 동시에 잔류염소농도 균등화를 고려하기 위한 염소 투입 및 재투입 최적화 방법을 제안하였다. 제안된 방법은 국내 대규모 지방상수도를 대상으로 적용하였으며, 격자탐색법을 통해 다양한 염소 투입/재투입 계획을 비교 분석하고, 공급 잔류염소농도의 적합성 및 균등성을 중심으로 최적화한 결과를 제시하였다.

• 상하수도학회지
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• 제24권5호
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• pp.519-525
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• 2010

From the results of tracer test for the existing chlorine contactor in Y water treatment plant, $T_{10}$ and $T_{10}$/T were calculated as 130 min and 0.16, respectively. Therefore it required the modification schemes for improving hydraulic efficiency, surrogated by T10 and $T_{10}$/T, and disinfection performance. In this study, in order to reduce dead zone within contactor, the installation of porous baffles in the near of each corner was suggested and verified using transient CFD(Computational Fluid Dynamics) simulation technique and tracer tests on dynamic condition. From the results of simulation and tracer tests, it was revealed that porous baffles installed have been effective to reduce dead zone within contactor, and increase plug flow fraction.

• 한국식품저장유통학회지
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• 제24권2호
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• pp.312-319
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• 2017

신선 농산물의 비가열 살균에 사용되는 살균소독제는 처리시간과 살균소독제의 농도에 비선형적인 감균효과를 나타낸다. 따라서 실제 사용에 있어서는 적정 농도와 적정 시간에 대한 고려가 매우 중요하다. 본 연구에서는 희석염산(6%, v/v)을 원료로 생성한 미산성 차아염소산수(slightly acidic electrolzyed water, SlAEW)($20{\pm}1^{\circ}C$에서의 유효염소 30 ppm, ORP $562{\pm}23mV$, pH 6.4)로 4종의 채소류(상추, 깻잎, 치콘 및 케일)에 대한 미생물 저감 특성을 분석하여 비가열 살균공정설계에 필요한 살균효과를 평가하였다. SlAEW에 30분간 3회 침지하면서 핵심인자인 유효염소와 미생물군수 및 잔류 미생물군수와의 관계를 분석하였다. 대부분의 총균수 감소는 1차 침지 초기 10분간 이루어졌으며 4종의 채소류에 생존하는 3 log CFU/g의 총균수가 침지를 통해 감소시킬 수 있는 한계값으로 판단되었다. 또한 SlAEW에 10분간 침지함으로써 감소시킬 수 있는 균수는 평균적으로 약 2 log CFU/g이었다. 초기 10분후의 감소된 유효염소는 상추, 깻잎, 치콘 및 케일에 대해 각각 2.2 ppm, 2.0 ppm, 1.7 ppm 및 2.5 ppm이었고 감소된 유효염소량의 약 50-80%가 초기 10분내에 감소되었다.