• Journal of dental hygiene science
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• v.15 no.4
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• pp.383-392
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• 2015

Dental chair unit (DCU) is the most essential equipment for the dental treatment in dentistry. DCU output water is used for various applications during dental treatment. DCU output water must be clean at the same level as drinking water since patients and dental staff are regularly exposed to water and aerosols generated from the DCU. Many studies demonstrated that DCU output water is frequently contaminated with microorganisms including opportunistic pathogen such as Legionella and Pseudomonas species. Thus, DCU output water may be a potential source of infection. In order to reduce microbial contamination levels in DCU output water, periodic management and continuous disinfection are necessary. Currently, there are a variety of disinfection methods for managing DCU output water and its efficacy is also diverse. We reviewed the level of microbial contamination, clinical implications of contaminated DCU output water and the various DCU disinfection methods.

• Journal of Environmental Policy
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• v.4 no.2
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• pp.57-82
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• 2005

In this study, we propose methods for. the efficient management and integrity of groundwater in response to a diminishing supply. As an alternative water resource for the future. we investigated and comparatively analyzed the quality standards of groundwater in the US (New York, Wisconsin and Texas), Austria, Netherlands, Canada, Japan and United Kingdom. These developed countries heavily depend on groundwater, more than 70%, for drinking water and apply those drinking water standards to groundwater quality. However, there exists few differences in the quality standards of groundwater among the countries, because each country possesses its own individual environment and management. In Korea, surface water pollution is getting serious and its water resources are diminishing. Therefore we propose several new quality criteria that many countries regulate at these days for their efficient management of groundwater. There is a need to divide BTEX criterion into Benzene, Toluene, Ethylbenzene and Xylene, individually. In. addition, it is needed to establish BTEX criteria into agricultural water and industrial water use standards as well as daily life use standards. Also, regulations for some PAHs, showing carcinogenicity, are required. Due to rapid industrialization various hazardous chemicals were utilized and their uses are increasing each year. Therefore, there is a strong need to introduce n~w standards and tighter regulations of the levels. At the same time, the criterion of nitrogenous compounds need' to be regulated individually in order to prevent the damage incurred by the compounds. Several developed countries have established standards for radon, previously caused environmental accidents in Korea. Therefore, we propose the necessity of groundwater quality standards for radon in this study.

• Food Science and Preservation
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• v.13 no.2
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• pp.234-240
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• 2006

The purpose of this study was to evaluate microbiologically cooking utensils, equipment employees, and environment in 12 large Korean, Western, Chinese, and Japanese restaurant. Microbiological testing was conducted for pathogens including E. coli, Samolnella, L. monocytogenes, S. aureus, E. coli O157:H7, V. parahaemolyticus, B. cereus, and Y. enterocolitica as well as total plate count and coliforms. The results showed cooking water and drinking water in some Korean restaurants and drinking water in some Western and Japanese restaurants were unsatisfactory, especially, barley tea, which was cooled after being boiled, was unsatisfactory. Most cooking utensils such as knives, cutting boards, kitchen towels, tongs, and basket had total plate and coliforms count in excess of standards, and knives and cutting boards at some Chinese restaurant had E. coli. At some restaurant, S. aureus was found on some food worker's hands. Also, the total plate count of the air showed a high count around worktables, inside the refrigerator, and in the kitchen in most restaurants. These result suggest that sanitation needs improvement in the environments in these foodservice establishment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.482-486
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• 2004

울산지역 수질특성에 관하여 연구하기 위해 228개 지점에서 수질성분 25개 항목을 분석하였다. 그 성분중 지하수 음용수 9개 수질성분(pH, EC, TDS, Cl, Mn, NO$_3$, SO$_4$, F, Fe)에 관해 수질분포특성 및 오염도를 나타내기 위해 모수적 통계기법인 정규크리깅과 비모수적 통계기법인 지시크리깅 기법을 적용하였다. OK와 IK의 성분별 베리오그램 분석한 결과 OK의 경우 모든 수질성분은 구상형모델(Spherical model)로 선정되었으며, IK의 경우 pH, TDS, SO$_4$, Cl, Mn, F, Fe 성분은 구상형모델로, EC는 지수형모델로, NO$_3$는 선형모델로 선정되었다. 그 결과 정규크리깅의 경우 연구지역의 수질특성을 정량적 분포특성이 잘 나타났다. 특히 태화강, 인접한 남구일원과 중구일원, 북구의 북서 일원 그리고 동구의 방어동일원에서 수질성분 9개 성분들이 다소 높게 나타났다. 특히 EC, TDS 그리고 Cl$^{-}$ NO$_3$ 성분이 높게 나타났다. 그리고 지시크리깅의 경우 정규크리깅과 비교하여 이상치가 크게 영향을 미칠 수 있는 통계학적인 오류를 보완하여 분석한 결과 울산지역 9개 성분 오염도는 EC>TDS>NO$_3$>pH>Fe>Mn>Cl>SO$_4$>F 순으로 오염특성이 나타났다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.791-794
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• 2008

The transport and dispersion of pollutants in natural river is a principal issue in intake station management. To study the pollutant transport in natural rivers, the effect of meandering and confluence of tributary on mixing process have to analyzed. The objective of this study is to simulate the mixing and transport of pollutants for operating water gate of Nakdong Estuary Barrage around the intake station. Mulgeum intake station being used as drinking water sources for Pusan. The flow around the intake station is influenced by operating water gate of Nakdong Estuary Barrage which is located downstream. The water gate system includes ten individual gates. The minor gate is usually opened according to elevation of the sea. When the river flow increases, the main water gate is opened. Daepo stream, tributary of the Nakdong river, is on opposite side of the intake station. The pollutants from Daepo stream often flows into the intake station acoording to the flow pattern. In this study, based on this simulation results, proper water gate operation which can minimize negative impact will be provided.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.224-231
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• 2019

Recently, the pollution of groundwater has become serious. In particular, the contamination of groundwater near livestock farms is becoming increasingly severe and it is difficult to drink with drinking water. In this paper, a groundwater purifier apparatus that can be installed in a community well was designed. The designed groundwater purifier apparatus enables a RO membrane filter and UV sterilization to remove pollutants, such as heavy metals, bacteria, and organic compounds. In addition, electrical conductivity, pressure, and flow sensors were added for remote monitoring. Remote monitoring of the system can determine the level of fouling and contamination of RO membrane filters through pressure and flow sensor data, and can record changes in the contamination and condition of groundwater through the electrical conductivity of the feed water. The designed groundwater purifier apparatus was installed at a farmhouse and remote monitoring. The result after 15 days of operating a groundwater purifier apparatus and analyzing the monitoring data revealed an average permeate water flow rate of 2.67L/min and an average water pressure of 7.09kgf/㎠, indicating that the RO Membrane filtered without fouling and clogging. The average electrical conductivity was 796.6 S/㎠ of the feed water and 55.6 S/㎠ of permeate water, which is similar to that of general tap water. Through this, it was confirmed that no pollutant occurred in the surroundings. Therefore, the designed groundwater purifier apparatus can confirm the replacement time of the RO membrane filter in advance through remote monitoring, and check the pollution state of the groundwater.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.187-192
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• 1997

We carried out a survey on tributary streams in some agricultural areas along Nakdong River to evaluate the effects of agricultural practices on pollution of stream water and groundwater. General properties, nutrient materials and heavy metals in water samples were measured. General physicochemical properties of tributary stream waters were at levels favorable for agricultural water. Heavy metals, except Zn, were mostly not detected. Total-N contents were much higher than the criteria of agricultural water, and nitrate-N accounts for more than a half of total-N. Phosphorus contents were higher than the lower level of P for algae growth and the contents were high especially in summer. In ground waters which are used for irrigation, P were mostly at same levels as those in streams, and nitrate contents were higher than 10mg/L in some samples. In these results only those N and P contents in stream and ground waters higher than pollution criteria are problematic and they are traceable to agricultural nonpoint sources-fertilizers, livestock farms and sewage. Further researches are needed to evaluate contributions of each nonpoint source on stream water pollutions.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.383-384
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• 2003

오존은 산업적으로 널리 활용되고 있으며 특히, 매우 넓은 환경공학적 응용분야를 가지고 있다. 오존의 산업적 적용은 1900년대 초부터 음용수 처리를 위해 시작되었으며 현재까지 폐수처리, 화학물질 합성, 재료의 부식 정도 측정, 수영장 소독, 치료용 목적, 냉각수 살균, pulp bleaching, 악취 및 대기 오염물질 처리 등의 광범위한 산업적 응용분야를 가지고 있다. 오존을 생성시키기 위한 대표적인 공정으로는 무성방전(dielectric barrier discharge, DBD) 공정, 전기 분해법(electrolysis), 자외선 조사법(UV irradiation)을 들 수 있으며 가장 널리 활용되고 있는 공정은 1857년 Simens에 의해 개발된 DBD 공정이다. (중략)

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.140-142
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• 1998

돈사에서 발생하는 폐수는 주로 돈뇨와 음용수의 누수 및 세척수 등으로 구성되어 있는데, 생물학적인 축산폐수처리법과 퇴비화법 등으로 처리를 하고 있다. 그러나 일반적인 돈사폐수에는 분의 함량이 많아 부유물질의 양이 많고 유기물 등 오염성분의 농도가 높은 특성을 가지고 있어서 기존의 생물학적 축산폐수 처리법으로는 과부하 운전으로 인한 어려움이 있고, 퇴비화법으로는 수분조절제의 소요량이 많은 문제점을 가지고 있다. 대부분의 현지 양돈농가에서는 돈뇨 등 폐수처리의 어려움으로 인하여 분뇨 분리 시설이 있어도 분뇨를 혼합한 슬러리 형태로 퇴비화하고 있다. 따라서 퇴비화 공정에서 수분조절제로 쓰이는 톱밥의 소요량이 돈분만 퇴비화할 때보다 훨씬 많고 기존의 퇴비화 시설도 과부화 상태로 운전하고 있는 실정이다.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.504-515
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• 2012

Groundwater is widely used as drinking water supplies around the world. However, microbial contamination of groundwater is a serious environmental problem that degrades drinking water quality and poses a great threat to human health. Among the pathogenic microorganisms such as viruses, bacteria, and protozoa, viruses are not readily removed during transport through soils, having high mobility in groundwater environment due to their smaller size compared to bacteria and protozoa. Studies regarding the fate and transport of viruses in soils and aquifers are necessary to determine the vulnerability of groundwater to microbial contamination and to secure safe drinking water sources. Also, these studies provide important information to establish the regulations and policies related to public health. This review paper presented the field and laboratory studies conducted for the fate and transport of viruses in subsurface environments. Also, the paper provided the factors affecting the fate and transport of viruses, the characteristics of bacteriophages used for virus studies, and virus transport model/colloid filtration theory. Based on this review work, future researches should be performed actively to set up the viral protection zone for the protection of groundwater from viral contamination sources. Especially, the researches should be focused on the development of mathematical models to calculate the setback distance and travel time for the viral protection zone along with the accumulation of information related to the model parameters.