• Journal of Korean Society of Water and Wastewater
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• v.28 no.3
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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.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.653-661
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• 2007

The Disinfectants/Disinfection By-products (D/DBP) Rule proposed by the US Environmental Protection Agency requires the implementation of enhanced coagulation as a control strategy for natural organic matter (NOM) removal and as a means of limiting the formation of all DBPs, i.e., not just the trihalomethanes and haloacetica acids. To control DBP formation, several best available technologies (BATs) were determined for removal of DBPs and DBP precursors. The enhanced coagulation is one of the BATs for DBP precursors removal. Treatment facilities that achieve a specified percent removal of total organic carbon (TOC) prior to the application of a continuous disinfectant or that achieve a residual TOC concentration < 2mg/L prior to the application of a continuous disinfectant are considered to be in compliance with enhanced coagulation. The enhanced coagulation was applied to raw water in Korea, the Han River. Raw water were examined and effects of different raw water qualities on enhanced coagulation were investigated. Three analyses were used for raw water characteristics, water quality measurement, molecular weight distributions, hydrophobic/hydrophilic fractionation. The Han River had the relatively low alkalinity and low organic carbon concentration. The results of molecular weight distributions showed significant portions of low molecular weight organics, which is very different from most water in USA. The alum doses for the required TOC removal guided from USEPA manual were quite low (i.e. 10~30 mg/L alum) for the water, probably due to the specific water quality of the Han River.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5792-5799
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• 2013

The purpose of this study was the Application of the HACCP (Hazard Analysis Critical Control Point) system to Korean Rice Cakes. Main ingredients of rice cakes, work facilities and workers were provided from KB company located in Seogye-dong Yongsan-gu, Seoul between September 12, 2012 and February 13, 2013. The manufacturing process chart was prepared by referring to the manufacturing process of rice cake manufacturers in general. As a result of this study, the microbiological hazard analysis on raw materials and finished products of rice cakes showed safe result. However, microorganism test on the manufacturing environment and workers suggested that microbiological hazard should be reduced through systematic cleaning and disinfection, accompanied by improved personal hygienes based on hygienic education on workers and management of microorganisms in the air.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.169-169
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• 2003

In Korea, there is no CRA studies and has not well known CRA and not well established their methodologies. Therefore, objectives of this study is to establish the framework of CRA consisting of health risk, economic risk and perceived risk and the detail methodologies of three main component of estimating and comparing those risks for on the three environmental problems of air pollution, indoor air pollution and drinking water contamination which being subjective to the eight sub-problems of hazardous ai. pollutants (HAPs), regulated pollutants (representative as PM10) and Dioxins (PCDDS/ PCDFs) in air pollution, and indoor ai. pollutants (IAPs) and Radon in indoor air pollution, and drinking water pollutants (DWPs), disinfection-by- products(DBPs) and radionuclides in drinking water contamination in Seoul, Korea. And then, their problems set priorities by individual and integrated risk. As a results, ranking of health risk were the following order of indoor air pollution, air pollution and then drinking water contamination, in three environmental problems and of radon, PM10, IAPs, HAPs, DWPs, Dioxins, DBPs, and then radionuclides in eight sub-problems. And that of economic risk were the same order. In the contrary, ranking of perceived risk were the following order of air pollution, drinking water contamination, and then indoor air pollution, and of HAPs, Dioxins, radionuclides, PM10, DWPs, IAPs, Radon and then DBPs.

• The Korean Journal of Emergency Medical Services
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• v.21 no.1
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• pp.87-98
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• 2017

Purpose: This study investigated the use of infection management and the frequency of emergency equipment sterilization by emergency rescue crews to provide basic guidelines and suggestions for infection control. Methods: A self-reported questionnaire was completed by 160 emergency medical technician rescue crews in J area from May 7 to May 22 in 2015. The questionnaire consisted of 95 items, including the general characteristics of the subjects (8 items), the use of emergency equipment (33 items), the frequency of facility sterilization (33 items), infection control (12 items), vaccination (4 items), and the use of personal protective equipment (5 items). Results: In all, 97.3% of respondents were aware of the "Guidelines of Infection management for Rescue Operators' and 90.9% received training on infection control. A total of 72.7% and 47.3% of rescue centers were equipped with disinfection facilities and laundry rooms, respectively. The average frequency of sterilization was $3.17{\pm}0.75$, which significantly differed for teams with more clinical experience (p=.050) and teams with three members (p=.030). The average score for individual protective equipment supplies was $1.95{\pm}0.66$. Conclusion: For proper infection management of emergency equipment, our results suggest that the number of crew members should be increased for each ambulance, protective equipment and rescue products should be supplied, and the number of facilities for sterilization and laundry at rescue centers should be doubled.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1134-1140
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• 2010

Ozonation is a promising process that can effectively reduce the occurrence of micropollutants and pathogen in water. This study investigated the performance of ozonation for the removal of pharmaceuticals and personal care products (PPCPs) in secondary effluent from wastewater treatment plant. Moreover, the disinfection potential of ozonation applied for PPCPs removal was discussed. Secondary effluent filtered by sand filter was used for tested water, and ozonation was performed under 2, 4 and 6 mg/L of ozone doses. As a result, 6 mg/L of ozone dose (ozone consumption : 4.4 mg/L) was essential for the effective removal of 37 PPCPs in tested water. Several previous studies showed that the operation condition could achieve approximately 3 log inactivation of total coliform and enteroviruses. On the other hand, dissolved ozone concentration in tested water increased by 1.8 mg/L under 6 mg/L of ozone dose, probably resulting in the increase of bromate formation potential. This result implies that as alternatives to suppress the bromate formation potential during the oxidation of PPCPs by ozone, investigations on advanced oxidation processes are required.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.203-214
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• 2018

Ballast water treated by sodium dichloroisocyanurate (NaDCC) injection method in ballast water management system (BWMS) contains reactive bromine, chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on the marine environment. WET testing was carried out for eight marine and fresh water organisms, i.e. diatom, Skeletonema costatum, Navicula pelliculosa, green algae, Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer, Brachionus plicatilis, Brachionus calyciflorus and fish, Cyprinodon variegatus, Pimephales promelas. The WET test revealed that diatom and green algae were the only organisms that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50 % (EC50) values of 25.0 %, 50.0 % and over 100.0 %, respectively, in seawater conditions. In contrast, rotifer and fish showed no toxicities to the effluent in the all salinity conditions. Meanwhile, chemical analysis revealed that the BWMS effluent contained total of 25 DBPs such as bromate, isocyanuric acid, formaldehyde, chloropicrin, trihalomethanes (THMs), halogenated acetonitriles (HANs) and halogenated acetic acids (HAAs). Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the all DBPs did not exceed 1.0 for general harbour environments, but isocyanuric acid, tribromomethane, chloropicrin and monochloroacetic acid exceed 1.0 for near ship environments. However, when NOEC (25.0%) of the WET test results where actual effluent was applied, it was concluded that the NaDCC injection method did not have unacceptable ecological risks to the general harbor including near ship environments.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.184-191
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• 2007

Coal-, coconut- and wood-based activated carbons and anthracite were tested for an adsorption and biodegradation performances of nitrogenous chlorinated by-products such as chloropicrin, DCAN, DBAN and TCAN. In early stage of operations, an adsorption performance was a main mechanism for removal of nitrogenous chlorinated by-products, however as increasing populations of attached bacteria, the bacteria played a major role in removing nitrogenous chlorinated by-products in the activated carbon and anthracite biofilter. It was also investigated that the compounds were readily subjected to biodegrade. Whilst the coal- and coconut-based activated carbons were found most effective in adsorption of the compounds, the anthracite was worst in adsorption of the compounds. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria were inhibited for removal of the compounds at temperatures below $10^{\circ}C$. The attached bacteria were more active at higher water temperatures$(20^{\circ}C\;<)$ but less active at love. water temperature$(10^{\circ}C\;>)$. The removal efficiencies of the compounds obtained using coal-, coconut- and wood-based activated carbons and anthracite were directly related to the water temperatures. In particular, water temperature was the most important factor for removal of the compounds in the anthracite biofilter because the removal of the compounds depended mainly on biodegradation. Therefore, the main removal mechanism of the compounds the main mechanism on the removal of the compounds using activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that using coal-based activated carbon is the best for removal of nitrogenous chlorinated by-products in the water treatment.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.237-247
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• 2012

This study assessed the removal characteristics of taste and odor causing compounds (2-methylisoborneol and geosmin) and organic matters, using a pilot-scale ozone/granular activated carbon ($O_{3}$/GAC) process treating surface water of Pal-dang reservoir in the Han river over a 3-month period. Experiments were conducted to verify the removal efficiency of $O_{3}$/GAC process which has two different empty bed contact time (EBCT) ($O_{3}$/GAC column 1 : 10 min and 2 : 15.1 min) with 10.86 min contact time of ozonation at 1.0 mg/L $O_{3}$. Spiking test using geosmin and 2-MIB was also conducted systematically to mimic the conditions when the algae appears, specifically at the levels similar to the concentrations experienced (geosmin: 250 ng/L) in the winter of 2011. In single ozonation process, organic materials, disinfection by-products (DBPs) and their precursors were disassembled but not removed completely. Meanwhile, it was verified that organic matters, taste and odor causing compounds, and DBPs were well removed when sequentially passing through the GAC process. The pilot results also showed that GAC column with larger EBCT achieved higher removal efficiency. Specifically, in spiking tests, single $O_{3}$ process showed approximately 89% removal efficiency of geosmin and 2-MIB. $O_{3}$/GAC combined process demonstrated excellent removal of geosmin and 2-MIB, which are higher than 95%.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.244-249
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• 2018

Objectives: The purpose of this study was the investigation of bromide and bromate in drinking water of water supply plants, mineral springs and small water supply system located in northern area of Gyeonggi province. Methods: Analytical method was based on EPA 326.0 to use Postcolumn reaction (PCR). The instrument was 887 professional UV/VIS detector IC manufactured in Metrohm. Results: Bromate was detected at $0.5{\sim}2.4{\mu}g/L$ in tap water from 5 water supply plants. These plants were used as disinfection method for sodium hypochlorite and on-site chlorine that causes generate bromate as a by products even if not used ozone. Conclusions: The bromate was detected up to $2.5{\mu}g/Lin$ drinking water in northern Gyeonggi area that showed within $10{\mu}g/L$ for standard of tap water. However, the continuous monitoring of bromate is necessary in drinking water.