• 상하수도학회지
• /
• 제31권5호
• /
• pp.421-430
• /
• 2017

In this study, a model was developed to predict for Disinfection By-Products (DBPs) generated in water supply networks and consumer premises, before and after the introduction of advanced water purification facilities. Based on two-way ANOVA, which was carried out to statistically verify the water quality difference in the water supply network according to introduce the advanced water treatment process. The water quality before and after advanced water purification was shown to have a statistically significant difference. A multiple regression model was developed to predict the concentration of DBPs in consumer premises before and after the introduction of advanced water purification facilities. The prediction model developed for the concentration of DBPs accurately simulated the actual measurements, as its coefficients of correlation with the actual measurements were all 0.88 or higher. In addition, the prediction for the period not used in the model development to verify the developed model also showed coefficients of correlation with the actual measurements of 0.96 or higher. As the prediction model developed in this study has an advantage in that the variables that compose the model are relatively simple when compared with those of models developed in previous studies, it is considered highly usable for further study and field application. The methodology proposed in this study and the study findings can be used to meet the level of consumer requirement related to DBPs and to analyze and set the service level when establishing a master plan for development of water supply, and a water supply facility asset management plan.

• Journal of Nutrition and Health
• /
• 제37권8호
• /
• pp.722-731
• /
• 2004

The objective of this study was to evaluate the microbiological quality of non-heat-processed foods for implementation of a HACCP (Hazard Analysis and Critical Control Point) system in day-care center foodservice operations. The evaluating points were microbial assessment of foods, utensils, and employee's hands during preparation, cooking, and serving. The temperature of non-heated food being served was also measured. Microbiological quality was assessed using 3 M Petrifilm/syp TM/ to measure total plate count and coliforms for food and utensils and Staphylococcus aureus for hands in five Gumi day-care centers. Results showed low microbiological quality of non-heated foods. This was probably due to contaminated raw ingredients and cross-contamination that occurred during preparation and cooking (e.g., unsatisfactory washing and disinfection of raw materials and utensils). These results suggest that it is essential to educate employees on good personal hygiene (hand washing) , prevention of cross-contamination through use of properly washed and sanitized utensils, and proper washing and disinfection of raw vegetables. Establishing Sanitation Standard Operating Procedures (SSOPs) are an essential part of any RACCP system in day-care center foodservice operations.

• 상하수도학회지
• /
• 제30권1호
• /
• pp.9-17
• /
• 2016

Disinfectant/oxidation process is a crucial process in water treatment for supplying safe drinking water. Chlorination is still widely used for water treatment area due to its effectiveness on microbial inactivation and economic feasibility. Recently, disinfection concern in marine environment is increasing, for example, movement of hazardous marine organism due to ballast water, marine environmental degradation due to power plant cooling water discharge, and increase of the amount of disinfectant in the offshore plant. It is needed to conduct the assessment of disinfectant behavior and the development of disinfectant prediction model in seawater. The appropriate prediction model for disinfectant behavior is not yet provided. The objective of the study is to develop chlorine decay model in seawater. Various model types were applied to develop the seawater chlorine decay model, such as first order decay model, EPA model, and two-phase model. The model simulation indicated that chlorine decay in seawater is influenced by both organic and inorganic matter in seawater. While inorganic matter has a negative correlation with the chlorine decay, organic matter has a positive correlation with the chlorine decay.

• 미생물학회지
• /
• 제45권4호
• /
• pp.346-353
• /
• 2009

이식을 위해 사용하는 사람 양막은 기증자로부터 수혜자에게 바이러스, 세균, 진균과 같은 감염성 위해인자를 전파할 위험이 있다. 따라서 적절한 소독 및 멸균 공정을 통해 이식용 양막 내재 또는 혼입 가능한 감염성 위해인자를 완벽하게 불활화하여야 한다. 본 연구에서는 인체조직은행에서 사용하고 있는 소독 공정과 멸균 공정의 바이러스 및 세균, 진균 불활화 효과를 검증하기 위해 국제적 가이드에 따라 5종의 바이러스[human immunodeficiency virus type 1 (HIV-1), bovine herpes virus (BHV), bovine viral diarrhoea virus (BVDV), hepatitis A virus (HAV), porcine parvovirus (PPV)]와 2종의 세균(Escherichia coli, Bacillus subtilis), 1종의 진균(Candida albicans)을 생물학적 지표로 사용하였다. 양막에 각 생물학적 지표를 첨가한 후 70% 에탄올 소독 공정, 감마선 조사 공정, 산화에틸렌 가스 멸균 공정을 실시한 다음 각 바이러스, 세균, 진균을 회수하여 정량한 후 불활화 정도를 비교하였다. 70% 에탄올 처리 공정에서 HIV-1, BHV, BVDV 같은 외피 바이러스는 처리 시간 2.5분 안에 불활화되었지만, HAV와 PPV 같은 비-외피 바이러스는 에탄올에 매우 큰 저항성을 나타내었다. 감마선 2.5 kGy 조사에 의해 HIV-1, BHV, BVDV는 검출한계 이하로 완벽하게 불활화되었다. HAV와 PPV는 각각 5 kGy와 25 kGy 조사에 의해 검출한계 이하로 불활화되었다. 산화에틸렌 가스 처리에 의해 본 연구에 사용한 모든 바이러스가 검출한계 이하로 불활화되었다. 70% 에탄올 처리 공정에서 E. coli와 C. albicans는 모두 5분 안에 완벽하게 사멸하였다. 하지만 B. subtilis는 큰 저항성을 나타내었다. 감마선 조사 공정과 산화에틸렌 가스 멸균 공정에서 E. coli, B. subtilis, C. albicans 모두 완벽하게 불활화되었다.

• 한국유기농업학회지
• /
• 제25권2호
• /
• pp.345-355
• /
• 2017

본 연구는 황토유황을 활용하여 벼 키다리병 발병을 최소화할 수 있는 최적 종자소독조건을 선발하기 위해 수행되었다. 키다리병에 이병된 '신동진' 품종 벼 종자를 공시하였고 황토유황 농도, 침지온도, 시간, 온탕여부를 구분하여 실내 및 온실검정을 통해 침지시간은 48시간, 침지농도는 1%로 최적 소독조건을 선발하였다. 그리고 모판과 포장시험을 수행하여 온탕처리 후 $20^{\circ}C$, 1% 황토유황에 48시간 침지 처리구와 $30^{\circ}C$, 1% 황토유황에 48시간 단독 침지할 때 가장 효과가 높았다는 것을 확인하였고 위 처리조건으로 소독한 종자가 육묘, 이앙, 출수기를 거치면서도 100%의 높은 방제효과가 유지되는 것을 확인할 수 있었다. 그러나 $20^{\circ}C$에서 1% 황토유황으로 침지한 처리구에서는 포장에서 78.2%의 낮은 방제가를 보였다. 또한, 온탕소독만 수행한 처리구에서도 $60^{\circ}C$, 10분간 충실히 수행될 경우 효과적인 벼 키다리병 방제가 가능함을 보여주었지만 온탕처리 후 황토유황으로 추가 침지함으로서 많은 양의 종자를 소독할 때 좀 더 나은 키다리병 방제 효과를 가져다 줄 수 있을 것으로 판단된다. 이상의 결과를 종합하여 볼 때 농가에서 온탕소독기와 종자소독기 둘 중 한가지만 구비하더라도 황토유황을 이용하여 충분한 소독효과를 낼 수 있기 때문에 현장에서 보다 쉽게 활용될 수 있을 것으로 판단되며 제조방법이 쉽고 비용이 적게 드는 황토유황의 특성상 농가의 경영비 절감효과도 클 것으로 기대된다.

• 한국환경과학회지
• /
• 제21권7호
• /
• pp.797-804
• /
• 2012

A dielectric barrier discharge (DBD) plasma reactor was investigated for the inactivation of Ralstonia Solanacearum which causes bacterial wilt in aquiculture. The DBD plasma reactor of this study was divided into power supply unit, gas supply unit and plasma reactor. The plasma reactor consisted of a quartz dielectric tube, discharge electrode (inner) and ground electrode (outer). The experimental results showed that the optimum 1st voltage, 2nd voltage, air flow rate and pH were for 100 V (1st voltage), 15 kV (2nd voltage), 4 L/min, and pH 3, respectively. At a low 1st voltage, shoulder and tailing off phenomena was observed. The shoulder phenomenon was decreased as the increase of 1st voltage. R. Solanacearum disinfection in the lower air flow rate was showed shoulder and tailing off phenomenon because the active species generated less. Under optimum condition, shoulder and tailing off phenomenon was reduced. When the 2nd voltage was less than 7.5 kV, tailing off phenomenon was observed and this was not vanishes even though the increase of the disinfection time. The inactivation efficiency increased as the increase of air flow rate, however, the efficiency decreased when the air flow rate was above 4 L/min. R. Solanacearum disinfection at pH 3 showed somewhat higher than in pH 11. The pH effect of R. Solanacearum deactivation is less than the impact on other factor.

• 상하수도학회지
• /
• 제30권5호
• /
• pp.587-596
• /
• 2016

This study attempts to draw factors for an analysis of the operation effect of a rechlorination facility and autodrain equipment for residual chlorine equalization by installing and operating a rechlorination facility and autodrain equipment in P City and analyzing the practical evaluation method and operation effect. For this purpose, this study selected three indicators for an analysis of the effectiveness of residual chlorine equalization and conducted a comparative analysis before and after the implementation of the residual chlorine equalization. As a result of estimation, (1) the reduction of the residual chlorine concentration range from a water treatment plant to the pipe end was 16.0%; (2) the total reduction of chlorination input was 18.0%; and (3) the reduction of the generation of disinfection by-products was 19.5%. In addition, this achieved enough residual chlorine equalization in the supply process and shows that it could successfully achieve the economic feasibility of investment in equipment and the reduction of the generation of disinfection by-products. Like this, it is judged that the three indicators suggested in this study will be used sufficiently as indicators of an analysis of the effectiveness of residual chlorine equalization according to the operations of the rechlorination facility and autodrain equipment.

• 식품과학과 산업
• /
• 제53권3호
• /
• pp.277-283
• /
• 2020

식품의 보존성 및 안전성 증대를 위해 살균이 필수적이다. 일반적으로 가열 살균 기술이 가장 많이 사용되고 있으나, 공정 중 식품의 품질 저하를 막기 위한 살균 기술로 신공정 기술을 활용한 비가열 살균 기술의 중요성이 대두되고 있다. 그 중에서도 초음파 기술은 특유의 캐비테이션 현상으로 미생물의 파괴가 촉진되어 살균 효과를 내는 것으로 알려져 있다. 초음파 기술 단독으로는 사멸 효과가 낮으며, 다양한 공정기술과 함께 적용하여 사멸 효과를 극대화할 수 있는 기술 개발을 위한 연구가 활발히 진행되고 있다. 초음파와 함께 처리할 수 있는 공정으로는 가열, 고압, 화학적 처리 등 전통적인 살균 방법 뿐 아니라 자외선 조사, PEF 등 신공정 기술이 있다. 초음파 기술을 적용한 다른 공정과 달리 살균 기술은 아직 실험실 수준에 머물러 있어 산업적 적용을 위한 장치의 개발, 최적 공정 확립 등 추가 연구가 필요하다.

• 한국물환경학회지
• /
• 제26권3호
• /
• pp.406-412
• /
• 2010

Concentrations and speciations of Trihalomethanes (THMs) and Haloacetic acids ($HAA_5$) that can be formed during chlorine disinfection by-product (DBPs) in full-scale drinking water treatment plants were investigated. Jeon-ju D water treatment plant that adopted conventional water treatment processes was chosen for investigation. SUVA values according to water treatment process changes were observed from 1.3 to 2.1. The process average concentrations of THMs was 7.4 ppb, 9.0 ppb and 14.7 ppb respectively, while the average concentrations of $HAA_5$ by each process which are precipitation water, filterater water, treated water, were 15.5 ppb, 14.9 ppb and 25.8 ppb respectively. DBPs concentrations was lower in the winter than summer. The major species of THMs was chloroform and the second highest was bromodichloromethane (BDCM) and the third highest was dibromochloromethane (DBCM). In case of $HAA_5$, the rate of trichloroacetic acid (TCAA) was detected. The species disribution of THMs is related to the change of SUVA and species disribution of $HAA_5$ is related to the concentrations of bromine and injection position of chlorine and injection quantity.

• 상하수도학회지
• /
• 제32권1호
• /
• pp.55-65
• /
• 2018

It is necessary to develop a mobile water production system in order to provide stable water supply in case of disasters such as floods or earthquakes. In this study, we developed a modular mobile water production system capable of producing water for various uses such as domestic water and drinking water while improving applicability in various raw water sources. The water production system consists of three stages of filtration (sand filtration - activated carbon filtration - pressure filtration) to produce domestic water and an additional reverse osmosis process to produce drinking water. In laboratory and field experiments, the domestic water production system showed excellent treatment efficiency for particulate matter, but showed limitations in the treatment of dissolved substances such as dissolved organic matter. In addition, ultraviolet irradiation was considered as additional disinfection step, because it does not form precipitates of manganese oxides after disinfection. Reverse osmosis process was added to increase the removal efficiency of dissolved substances and the treated water satisfied drinking water quality standards. Fluorescence analysis of dissolved organic matter showed that the fulvic acid-like substances in raw water was successfully removed in the reverse osmosis process. The mobile water production system developed in this study is expected to be used not only in water supply in case of disaster, but also widely used in islands and rural area.