• 한국식품조리과학회지
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• 제24권4호
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• pp.445-451
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• 2008

This study compared the effects of chlorine dioxide and a commercial chlorine sanitizer for inhibiting foodborne pathogens, including Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Escherichia coli O157 : H7, on lettuce leaves. The lettuce samples were inoculated with each cocktail of the three strains, and were then treated with chemical sanitizers [distilled water, 100 ppm commercial chlorine and 50 ppm, 100 ppm, 200 ppm chlorine dioxide ($ClO_2$)] for 1 min, 5 min, and 10 min at room temperature($22{\pm}2^{\circ}C$). Following inoculation of the leaves, initial populations of E. coli O157:H7, L. monocytogenes, and S. Typhimurium were approximately 5.54, 4.47, and 5.12 log CFU/g, respectively these levels were not significantly reduced by the treatment with water,whereas the 100 ppm commercial chlorine sanitizer treatment and $ClO_2$ (at all tested concentrations) were effective at reducing levels of all three pathogens. The treatment of 200 ppm $ClO_2$ for 10 min was most effective at inhibiting the three pathogens, and reduction levels of E. coli O157 : H7, L. monocytogenes, and S. Typhimurium were 2.28, 1.95, 1.76 log, respectively. The inhibitory effect of $ClO_2$ increased with increasing treatment concentration of $ClO_2$, but there was no significant difference by the treatment times. When chemically injured cells of E. coli O157 : H7 and L. monocytogenes and S. Typhimurium were examined by SPRAB and selective overlay methods, respectively, it was observed that the commercial chlorine sanitizer generated greater numbers of injured L. monocytogenes than the $ClO_2$ treatment. From the overall results, $ClO_2$ was more effective at inhibiting pathogenic bacteria compared to the commercial chlorine sanitizer therefore, it has potential to be utilized as an alternative sanitizer to increase the microbial safety of fresh produce.

• 상하수도학회지
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• 제20권2호
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• pp.281-287
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• 2006

Maintaining adequate chlorine residual is crucial in water treatment facilities, Treatment technique, newly promulgated regulation, requires sufficient disinfection in order to control more resistant microorganisms such as Viruses and Giardia lamblia. Each water treatment plant should report various water qualities including chlorine residual and disinfection by-products, thus plenty of data has been generated. Even though statistical analysis using these data are forced to investigate the status and effect of water qualities in water facilities very few researches have been performed in korea. This study performed statistical analysis of chlorine residual during three years in Korean drinking water. The average chlorine residual concentrations were 0.701mg/L, 0.738mg/L, 0.763mg/L in 2002, 2003, 2004, respectively. Monthly variations of chlorine residual was not significant. ANOVA result showed that yearly variance of chlorine residual is different in only less than $5000m^3/day$ of water treatment capacity. The statistical analysis can help government to establish new regulation with scientific basis.

• 상하수도학회지
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• 제28권1호
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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.

• 한국식품영양과학회지
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• 제38권5호
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• pp.601-604
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• 2009

본 연구는 이산화염소수 처리가 식품에서의 잔류농약 제거에 효과가 있는지 조사하기 위해서 수행되었다. 10, 50, 100 ppm 이산화염소수로 채소류에 흔히 쓰이는 농약인chlrpyrifos, diazinon, metalaxyl을 처리하여 GC를 이용하여 농약의 분해율을 측정하였다. 상기 세 가지 농약 성분은 이산화염소수 처리 농도뿐만 아니라 처리시간에 비례하여 분해되었으며 특히 100 ppm 이산화염소수 처리가 가장 효과적이었다. 또한, 인위적으로 농약을 오염시킨 상추를 증류수, 100 ppm 이산화염소수에 각각 침지하여 농약의 제거율을 비교해 보았을 때, 100 ppm 이산화염소수에 10분 동안 침지하였을 때가 가장 효과가 좋았다. 본 연구 결과, 이산화염소수 처리는 신선농산물에서의 잔류농약을 제거하기 위한 세척수로 이용될 수 있을 것으로 판단된다.

• 상하수도학회지
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• 제7권2호
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• pp.34-38
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• 1993

An experimental study was conducted to investigate the effects of chlorine dioxide and ozone on reduction of THM(trihalomethane) formation. Precursor concentration, chlorine concentration, reaction time, pH, and temperature were governing compornents of THM formation. When other conditions are constant, THM formation increased linearly with precursor concentration increased. THM formation increased when pH increased from 5 to 9. In combined treatment with chlorine and chlorine dioxide, chlorine treatment after chlorine dioxide treatment made less THM than any other case does. Ozonation reduced THMFP(THM formation potential) of THM precursor. THMFP decreased exponentially with reaction time increased. Also biodegradability of humic acid was enhanced by ozonation.

• Food Science and Biotechnology
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• 제16권6호
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• pp.1018-1022
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• 2007

Effect of aqueous chlorine dioxide treatment on the microbial growth and quality changes of strawberries during storage was examined. Strawberries were treated with 5, 10, and 50 ppm of chlorine dioxide solution, and stored at $4{\pm}1^{\circ}C$. Total aerobic bacteria in strawberries treated at 50 ppm of chlorine dioxide were increased from 1.40 to 2.10 log CFU/g after 7 days, while increasing in the control from 2.75 to 4.32 log CFU/g. Yeasts and molds in strawberries treated at 50 ppm of chlorine dioxide were increased from 1.10 to 1.97 log CFU/g after 7 days, while the control was increased from 2.55 to 4.50 log CFU/g. The pH and titratable acidity of strawberries were not significantly different among treatments. Sensory evaluation results showed that chlorine dioxide-treated strawberries had better sensory scores than the control. These results indicate that chlorine dioxide treatment could be useful in improving the microbial safety and qualities of strawberries during storage.

• 상하수도학회지
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• 제21권5호
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• pp.601-607
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• 2007

In order to maintain constant residual chlorine in sedimentation basin, It is necessary to develop real time prediction model of residual chlorine considering water treatment plant data such as water qualities, weather, and plant operation conditions. Based on the operation data acquired from K water treatment plant, prediction models of residual chlorine in sediment basin were accomplished. The input parameters applied in the models were water temperature, turbidity, pH, conductivity, flow rate, alkalinity and pre-chlorination dosage. The multiple regression models were established with linear and non-linear model with 5,448 data set. The corelation coefficient (R) for the linear and non-linear model were 0.39 and 0.374, respectively. It shows low correlation coefficient, that is, these multiple regression models can not represent the residual chlorine with the input parameters which varies independently with time changes related to weather condition. Artificial neural network models are applied with three different conditions. Input parameters are consisted of water quality data observed in water treatment process based on the structure of auto-regressive model type, considering a time lag. The artificial neural network models have better ability to predict residual chlorine at sediment basin than conventional linear and nonlinear multi-regression models. The determination coefficients of each model in verification process were shown as 0.742, 0.754, and 0.869, respectively. Consequently, comparing the results of each model, neural network can simulate the residual chlorine in sedimentation basin better than mathematical regression models in terms of prediction performance. This results are expected to contribute into automation control of water treatment processes.

• 한국식품과학회지
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• 제36권3호
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• pp.514-517
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• 2004

본 연구에서는 이산화염소 처리를 이용하여 대표적 식중독 미생물인 E. coli O157:H7, Salmonella typhimurium, Listeria monocytogenes에 대한 살균 효과를 측정하였다. Pure cell culture 상태에서의 E. coli는 이산화염소 5 ppm에서 D-value가 3.37분으로 측정되었다. 그러나 Salmonella와 Listeria의 생존곡선은 이산화염소 처리시간에 따라 biphasic curve를 나타내었다. 이러한 biphasic curve는 5분까지의 처리로 해당 농도에서의 살균효과는 대부분 나타나고 그 이후는 효과가 없음을 보여주었다. 특히 Listeria의 5ppm과 10ppm의 처리결과는 이산화염소의 처리에 영향을 주는 인자 중 처리 시간보다는 처리농도가 더 큰 영향을 끼치는 것을 나타내었다. 본 연구 결과는 이산화염소 허용치인 5ppm이 신선채소에 대한 미생물학적 안전성을 확보 하기엔 부족하다는 것을 시사한다.

• 한국재료학회지
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• 제29권1호
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• pp.16-22
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• 2019

Indirect oxidation using chlorine species oxidizing agents is often effective in wastewater treatment using an electrochemical oxidation process. When chlorine ions are contained in the wastewater, oxidizing agents of various chlorine species are produced during electrolysis. In a ballast water management system, it is also used to treat ballast water by electrolyzing seawater to produce a chlorine species oxidizer. However, ballast water in the brackish zone and some wastewater has a low chlorine ion concentration. Therefore, it is necessary to study the chlorine generation current efficiency at various chlorine concentration conditions. In this study, the chlorine generating current efficiency of a boron-doped diamond(BDD) electrode and insoluble electrodes are compared with various chloride ion concentrations. The results of this study show that the current efficiency of the BDD electrode is better than that of the insoluble electrodes. The chlorine generation current efficiency is better in the order of BDD, MMO(mixed metal oxide), $Ti/RuO_2$, and $Ti/IrO_2$ electrodes. In particular, when the concentration of sodium chloride is 10 g/L or less, the current efficiency of the BDD electrode is excellent.

• 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.