• 상하수도학회지
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• 제23권3호
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• pp.331-337
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• 2009

Electrolysis produces hypochlorous acid by using a small quantity of NaCl as electrolyte. This process maximizes the stabilization of drinking water through the control of chlorine residual concentration. This study investigated free chlorine generation by an electrolytic method using $Ti/IrO_2$ and stainless steel. The generation of free chlorine was increased with increasing hydraulic retention time, voltage, chlorine ion concentration and the number of electrodes. However, the change of pH did not affect the generation of free chlorine. There was no significant difference on the behavior of chlorine concentration between electrolytic method and NaOCl injection. In this study, the concentration of free chlorine predicted model based on power functional model was developed various under conditions. Electrolysis free chlorine generation model can be effective tool in the estimation of free chlorine generation.

• 한국생산제조학회지
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• 제21권5호
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• pp.720-725
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• 2012

Sodium hypochlorite is used worldwide as a water disinfectant and in bleaching agent. Sodium hypochlorite applied to water initially undergoes hydrolysis to form free chlorine consisting of hypochlorous acid(HOCl) and hypochlorite ion($OCl^-$). For free chlorine determination, an electrochemical method is simple due to the electroactivity of free chlorine; it measures current and is free of most reagents. Amperometric free chlorine sensor has been developed with gold (Au)-based electrode. The 3-electrode free chlorine sensor whose working and counter electrodes were Pt exhibited excellent response to HClO at +400mV vs. Ag/AgCl/sat. KCl. In addition, the use of a pH error correction algorithm provided a reliable measurement of residual free chlorine in water sample without any pretreatment in the normal pH range(pH 6~8) of municipal water supply. The free chlorine sensor installed in on-line monitoring system could be used to continually monitor the level of residual free chlorine in real samples.

• 상하수도학회지
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• 제19권3호
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• pp.363-369
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• 2005

This paper presents the integrated technique of water quality analysis and Geographic Information System(GIS) for assessing the variation of free chlorine residuals by water temperature and supply distance in Sangri water supply system in Daegu. GIS was utilized for mapping projectmap, extraction of a pipeline route, and supply distance. Free chlorine residual is analyzed every month for appraising the seasonal variation. As a result, free chlorine residuals are affected both water temperature and water supply distance, and it becomes worse as water temperature and water supply distance is increased. To maintain 0.4mg/l of free chlorine residual, initial dose concentration should be over 1.85mg/l in summer.

• 한국식품과학회지
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• 제24권2호
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• pp.132-136
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• 1992

밀가루의 지방질 조성에 대한 염소처리의 영향을 연구하기 위하여 밀가루 100파운드당 1, 2 및 4 oz의 액화염소가스를 각각 처리하여 각종 지방질 성분의 변화를 비교하였다. 염소처리에 의해 극히 적은 양이지만 유리 지방질 함량은 증가한 반면 결합지방질은 감소하였다. 중성 지방질함량은 염소처리량 증가에 따라 유리 및 결합지방질에서 모두 증가하였다. 당지방질 함량은 염소처리량 증가에 따라 유리지방질에서는 증가한 반면 결합지방질에서는 감소하는 경향이었다. Triglyceride의 함량은 염소처리량 증가에 따라 유리 및 결합지방질에서 모두 감소하였다. Digalactosyl diglyceride의 함량은 염소처리량 증가에 따라 결합지방질에서는 감소하였으며, 유리지방질에서는 4 oz 처리는 급격히 감소하였다. 유리 및 결합지방질 중 phosphatidylcholine 함량은 염소처리량 증가에 따라 감소한 반면 lysophosphatidylcholine은 증가하였다. 염소처리량 증가에 따라 유리 및 결합지방질에서 포화지방산 함량은 증가하였고 불포화지방산의 함량은 감소하는 경향이었다.

• 자원리싸이클링
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• 제29권6호
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• pp.48-56
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• 2020

본 연구에서는 염소 함유 클링커 특성을 분석하기 위해 raw mix 제조 시 CaCl2를 첨가하였으며, 이때 염소 함량을 고농도 조건인 2,000ppm까지 제어하였다. 염소 첨가 raw mix의 소성온도는 1250℃에서 1350℃까지 조정하였으며, 각각의 최대온도에서 10분간 유지하였다. 모듈러스는 LSF-92.0, SM-2.5 및 IM-1.6으로 고정하였으며, 염소 함유 클링커의 소성성은 free-CaO 분석을 통해 확인하였다. 염소 함량 증가에 따라 free-CaO는 감소하였으며, 1350℃-2000ppm의 free-CaO 함량은 1.5%까지 낮아졌다. 염소 함량 증가에 따른 광물특성 확인을 위해 광학현미경 및 XRD를 활용하였다. 1250℃ 소성 시에는 클링커 광물을 관찰할 수 없었으며, 1350℃ 소성 시에는 염소 함량 증가에 따라 alite 크기가 소폭 증가하였다. 또한 염소 함량 증가에 따라 우수한 광물결정성을 발현되어 클링커 내 염소함량이 증가할수록 우수한 소성성 및 광물특성을 보였다.

• Environmental Analysis Health and Toxicology
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• 제13권3_4호
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• pp.77-85
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• 1998

It is very frequent that LAS meets the chlorine bleaches not only in the processes but also in the path from the sewages to the rivers. Therefore, it is not difficult to imagine that the harmful substances like DBPs are produced when LAs reacts with free chlorine. THMs are the major components of DBPs which are formed by reactions of organic substances with the chlorine oxidants. Among them, chloroform is the most noteworthy material. Since the major behavior observed was the formation of chloroform during reaction of LAS with free chlorine, the models were developed to grasp the tendency of chloroform formation depending on condition. According to these models, the effect of pH in the formation of chloroform is most grave.

• 한국환경보건학회지
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• 제31권2호
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• pp.147-151
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• 2005

The disinfection effect of free residual chlorine and monochloramine on biofilm communities were investigated by CLPP (community level physiology profile) using Biolog GN plates. Low concentration of disinfectant, $0.5\;mg/\iota$ free chlorine and $1.0\;mg/\iota$ monochloramine, stimulated the growth of bacteria rather than disinfection. Bacterial concentrations were decreased at more than $1.0\;mg/\iota$ of disinfectants. CLPP was different with the type and concentration of disinfectant and sampling time. Common and different carbon sources were actively used with similar bacterial concentration in free chlorine and monochloramine. This represents the differences of bacterial communities with tap water contact times and disinfectant.

• 상하수도학회지
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• 제28권1호
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• pp.91-101
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• 2014

Three water treatment plants(WTPs) in Jeju island whose source water have different characteristics from those of the mainland of Korea were investigated. Coefficients of bulk water decay($k_b$) of free chlorine at $5^{\circ}C$ for ES, GJ, NW WTPs were $-0.003hr^{-1}$, $-0.002hr^{-1}$ and $-0.001hr^{-1}$ respectively based on bottle tests. To simulate the free chlorine variations in the distribution system using EPANET, ES WTP was chosen. Free chlorine concentrations of several sites were less than the drinking water quality standards(i.e., 0.1 mg/L); E5(0.03 mg/L), E6(0.02 mg/L), W21(0.02 mg/L) and W25(0.03 mg/L). To maintain more than 0.1 mg/L of free chlorine in the distribution system, at least 1.9 mg/L of chlorine was needed at the WTP, which suggested rechlorination was needed to supply palatable tap water to customers. Two sites, one that diverged into E5 and E6 in the east-line and another located before E21 in the west-line were selected for the appropriate rechlorination locations. The recommended rechlorination dosages were 0.42 mg/L for the east and 0.27 mg/L for the west. The simulated results indicated that the free chlorine could be reduced to 0.4 mg/L at the WTP with rechlorination, and taps with excessive free chlorine could be more stabilized(i.e., 0.1~0.4 mg/L).

• 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.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.136-139
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• 2003

This study is to observe the occurrence of heterotrophic bacteria in terms of free chlorine residuals in two different water distribution system which belongs to both K and Y water treatment plant of S city of Korea. The data analyzing in distribution systems (DS) shows that the free chlorine residuals decrease from 0.10 to 0.56 mgmg/L for K, and 0.51 to 0.78 mg/L for Y. The decay of free chlorine is clearly higher in both March and August than those of in January. The HPC in DS are ranged from 0 to 40 CFU/mL for K, 0 to 270 CFU/mL for Y, on R2A medium. In particular, its level is relatively high at consumers ground storage tanks, taps and point-of-end area of Y. The predominant genera is studied in distribution systems are Acinetobacter, Sphingomonas (branch of Pseudomonas), Micrococcus, Bacillus, Staphylococcus. The diversity of heterotrophic bacteria increase in the end-point area. Most of them are either encapsulated cells or cocci of gram-positve. In conclusion, the point-of-end area in distribution systems shows the longer flow distance from water treatment plants, the greater diversity and higher level of heterotrophic bacteria due to the significant decay of free chlorine residuals.