• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2001년도 정기총회 및 제3회 특별지포지움
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• pp.122-140
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• 2001

유류오염물질의 매립 및 국부적인 유류누출에 의한 토양오염지역에서 시험탐사구역을 설정하고 전기, 전자탐사 기술을 위주로 물리탐사 기술을 적용하여 매설물 탐지 및 오염범위 규명 가능성을 시험하였다. 먼저 매설관로 및 매립지역의 탐지에는 GPR 탐사와 더불어 다중주파수 이동송수신 전자탐사가 매우 효과적인 것으로 판명되었다 한편 수직 및 수평구배 측정방식 자력탐사의 경우 지표에 많이 존재하는 금속 파편 등에 의한 반응이 우세하여 매설관로 등의 탐지는 어려웠다. 유류오염 범위의 규명을 위해서는 전기비저항 탐사와 전자탐사, GPR 탐사가 적용되었다. 먼저 전기비저항 탐사자료의 2차원 역산 결과 및 공간 필터링을 적용한 후의 전자탐사 자료의 1차원 역산 결과로부터 각각 심도별 전기비저항 분포 영상을 작성하였다. 유류오염대가 주변 실트층에 비해 전기비저항이 높다는 가정하에 고비저항 이상대의 분포범위를 해석하였는데, 전기비저항 탐사와 전자탐사자료가 서로 잘 일치하였으며, 시료분석에 의한 오염범위와 대체적으로 일치하였다. GPR 탐사에서는 이 지역의 오염 특성상 유류오염 Plume에 의한 반사신호 등은 기록되지 않았으며, 단지 신호 에너지의 투과심도로부터 오염지역을 추정하였는데, 전기 및 전자탐사자료 해석의 보조적인 정보 제공 수준이었다 이러한 결과로부터 유류오염부지 조사를 위한 물리탐사기술의 적용성을 정리하였고 효과적인 탐사 흐름도를 제시하였다.

• 지질공학
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• 제33권1호
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• pp.39-49
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• 2023

국내에서 관리되고 있는 토양오염물질 중 지질 기원의 영향이 큰 물질로는 비소, 카드뮴, 구리, 납, 아연, 니켈, 수은, 불소 등이 있다. 본 연구에서는 국내 토양오염 조사 자료를 바탕으로 GIS 모델링을 통해 오염물질의 분포 현황을 파악하고 오염원과의 공간적 개연성을 확인하였다. 그 결과, 카드뮴, 구리, 납, 니켈, 수은의 경우 1% 미만의 낮은 기준초과 빈도를 나타내고 있다. 비소와 아연의 경우 각각 광산 영향범위와 산업단지 부지 내에서 높은 초과 빈도를 나타내며, 주변 오염인자에 의한 영향이 매우 높은 것으로 확인되었다. 그러나 불소의 경우 조사지점 수가 가장 적고, 기준초과 빈도가 가장 높음에도 불구하고 뚜렷한 인위적 오염원이 확인되지 않았고, 분포 특성 또한 광역적인 연속성을 보임에 따라 지질 분포와의 개연성이 매우 높을 것으로 추정된다. 불소 항목의 기준초과 지점에 대한 지질 분포 현황을 확인한 결과, 쥐라기 화강암(40.00%)과 선캄브리아기 호상편마암(34.12%)에서 집중적인 초과 빈도를 나타내고 있다. 이는 화강암과 편마암에 존재하는 높은 불소 함량이 암석의 풍화에 따른 토양의 생성 과정에서 토양의 구성 성분으로 존재함에 따라 이들 암석이 분포하는 지역의 토양 중 불소 농도가 높게 나타난 것으로 판단된다.

• 한국정밀공학회지
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• 제27권1호
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• pp.33-40
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• 2010

In this research, the effects for surface Improvement of plasma ion implanted carbide endmill tools were observed by measuring cutting forces and tools wear affecting surface roughness in high speed cutting. From the 2nd ion mass analysis, the oxidation layer was found to be built up by sputtering. The residual gas contamination of oxygen was found to be contained impurities in nitrogen gas. The plasma implanted ion was found to be spreaded, especially the nitrogen was implanted up to 150nm depth as impressed voltage and ion implanting time. It is analyzed as bring surface improvement by spreading deeply forming oxidation on surface. The factors in Analysis of Variance(ANOVA) about mutuality cause reference of cutting force. The cutting force Fx is affected by the interaction of spindle rpm and federate, the cutting force Fy is influenced by spindle rpm and time injected ion, and cutting force Fz is affected by the interaction of impressed voltage and feedrate. Also, it was found that the cutting forces of implanted tools become lower and the surface roughness is improved by the effect of nitrogen according to the implantation.

• 한국물환경학회지
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• 제21권6호
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• pp.630-636
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• 2005

Groundwater contamination by nitrate exceeding water quality criteria (10 mg $NO_3{^-}-N/L$) occurs frequently. Fumarate, acetate, formate, lactate, propionate, ethanol, methane and hydrogen gas were evaluated for their nitrate removal efficiencies and removal rates for in situ bioremediation of nitrate contaminated groundwater. Denitrification rate for each substrate was in the order of: fumarate > hydrogen > formate/lactate > ethanol > propionate > methanol > acetate. Microcosm studies were performed with fumarate and acetate. When fumarate was used as a substrate, nitrate was removed 100 percent with rate of 0.66 mmol/day while conversion rate from nitrate to nitrogen gas or another by-product was 87 percent. 42 mg of fumarate was needed to remove 30 mg $NO_3{^-}-N/L$. When using acetate as carbon source, 31 percent of nitrate was removed during initial adjustment period. Among removed fraction, however, 83 percent of nitrate removed by cell growth. Overall nitrate removal rate was 0.37 mmol/day. Acetate showed longer lag time in consumption compared to that of nitrate, which implying that acetate would be better carbon source compared to fumarate as more amount was utilized for nitrate removal than cell growth.

• 환경위생공학
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• 제7권2호
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• pp.83-94
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• 1992

Recently water demand is increasing as the industry prospers. The increase of water demand is followed by the increase of wastewater discharge which pollutes rivers and ground water extensively. These rivers, reservoirs and ground water are sources for drinking water and their contamination affects the quality of water supply and other potable water. In Korea there are 776 water treatment plants which supply drinking water from main rivers or reservoirs. Rivers are the biggest water source for drinking water is being contaminated, the innovation of treatment process is needed. The construction and operation of water supply facilities is under the control of the Ministry of Construction and the water supply offices of cities and provinces. However, drinking water quality is under the control of the bureau of sanitation in the Ministry of Health and Social Affairs. There are 33 items in drinking water quality standards of Korea. Trihalomethanes, Selenium, Diazinone and other three of pesticides have been included lately, The Ministry of Health and Social Affairs is planning to enhance. the level of $VOC_S$(Vola-tile Organic Compounds) standard. Drinking water quality standard is the goal to protect the quality of supply water and ground water. In order to protect the source water from domestic or industrial water, technological improvement and adequate investment should be urgently made. The ultimate goal of drinking water quality is safety and health of consumers. The more stringent the standard are, the better the water quality will be. As the drinking water quality standards become more stringent this year, various and positive solutions by the authorities concerned must be prepared.

• 자원환경지질
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• 제26권2호
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• pp.175-185
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• 1993

Soils and dusts collected from Changhang smelter area were analyzed for Cu, Pb, Zn, and Cd in order to determine their dispersion pattern and mode of occurrences, and to investigate the pollution level of heavy metals such as Cu, Pb, Zn, and Cd by smelting activity. The soil pH of Changhang area is in the range of 3.7~8.8, and increased with increasing distance from the smelter site. The particles containing heavy metals are several tens of ${\mu}m$ in diameter, and have well crystal form. Samples collected near the smelter show similar particle properties in size, shape, and composition, which means that they could be originated from the same contamination source. Element couples of Cu, Pb, Zn, and Cd indicate high correlation with each other, which means that Cu, Pb, Zn, and Cd could be originated from the same point source of smelter. Heavy metal contents were decayed to background levels from 2.5 kilometer away from the smelter.

• 자원환경지질
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• 제26권2호
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• pp.217-226
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• 1993

Stream sediment samples were collected in the vicinity of the Sambo Pb-Zn-barite mine in order to investigate dispersion patterns and pollution levels of heavy metals, and to find out their mode of occurrences. Those samples were analyzed for Cd, Cu, Pb, Zn, Fe, and Mn by using partial extraction and sequential extraction methods. Stream sediments of this studied area has been contaminated severely by Pb, Zn, and Cd. Dispersion patterns of heavy metals in those sediments are different according to their pollution source and sampling distance from the mine. The stream sediment pH is generally neutral in control area, and is slightly acidic in the lower part of tailing dam. The main pollution source of stream sediments was confirmed as tailing and mine drainage. Their pollution level depends mainly on inflowed water and distance from the mine. The tolerance index ranges from -0.9 to 0.7. The mode of occurrances of heavy metals in polluted stream sediment are identified as Fe-Mn oxides, organic bounded and carbonate-bounded compound which show high potential of bioavailablity.

• 동력기계공학회지
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• 제18권6호
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• pp.106-112
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• 2014

The diesel engine, which has high compression ratio than other heat engines, has been using as the main power source of marine transport. Especially, since marine diesel engines offer better specific fuel consumption (SFC), it is environment-friendly compared to those used in other industries. However, attentio should be focused on emissions such as nitrous oxide ($N_2O$) which is generated from combustion of low-grade fuels. Because $N_2O$ in the atmosphere is very stable, the global warming potential (GWP) of $N_2O$ is 310 times as large as that of $CO_2$, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. It has been hitherto noted on the $N_2O$ exhaust characteristics from stationary power plants and land transportations, but reports on $N_2O$ emission from the marine diesel engine are very limited. In this experimental study, a author investigated $N_2O$ emission characteristics by using changed diesel fuel components of nitrogen and sulfur concentration, assessed on the factors which affect $N_2O$ generation in combustion. The experimental results showed that $N_2O$ emission exhibited increasement with increasing of sulfur concentration in fuel. However, all kinds of nitrogen component additives used in experiment could not change $N_2O$ emission.

• 한국환경과학회지
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• 제14권4호
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• pp.413-425
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• 2005

The 16 priority PAHs (Polycyclic Aromatic Hydrocarbons) designated by US Environmental Protection Agency were analyzed for some digested sludges from wastewater treatment plants in Korea. PAHs are an important group of organic contaminants present in sewage sludge due to their persistence and toxic potential. PAHs were extracted from freeze-dried sludges using a methylene chloride-methanol (2:1) mixture in a soxhlet extractor. The extracts were cleaned-up by silica gel/alumina combination column and subsequently fed into gas chromatograph/mass spectrometer (GC/MS) for determining PAH contents. The sum of the 16 PAHs in the sewage sludge varied from 534.8 to $5754.5 {\cal}ug/{\cal}kg$, dry wt.. In the sewage sludge, phenanthrene appears as the most abundant PAHs, followed by naphthalene, pyrene, fluoranthene. Source of the investigated sewage sludges relatively predominated pyrogenic. PAHs levels of sewage sludges in Korea appeared to be lower than those in other countries.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권4호
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• pp.27-35
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• 2012

Recently, there has been increasing interest in the use of rain garden systems as environmentally friendly ecological infrastructures for controlling stormwater runoff and managing non-point source pollution and information for the contamination of soil and plants can be essential for sustainable rain garden management. In this study, four rain garden mesocosms, namely single species planting with Rhododendron lateritium, single species planting with Zoysia japonica, mixed planting with R. lateritium and Z. japonica, and control without plants, were tested to investigate the change in concentrations of nutrients (N and P) and heavy metals (Cd, Cu, Pb, and Ni) in the soil and plants used in the rain garden system. The presence of plants resulted in greater nutrient retention in soil and lower potential leaching from the system. All systems showed an increase in the heavy metal concentrations in soil. The concentrations of most heavy metals were found to be higher in the herbaceous plants (Z. japonica) than in the shrubs (R. lateritium). The belowground part (root) had higher heavy metal concentrations than the aboveground part (leaf) but also showed a potential increase in leaves, and hence, careful plant management should be considered during rain garden operation.