• 한국지하수토양환경학회지:지하수토양환경
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• 제15권6호
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• pp.37-45
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• 2010

Surfactant-enhanced ozone sparging (SEOS), an advanced version of SEAS (surfactant-enhance air sparging) was introduced in this study for the first time for removal of non-volatile contaminant from aquifer. The advantages of implementing SEAS, enhanced air saturation and expanded zone of sparging influence, are combined with the oxidative potential of ozone gas. Experiments conducted in this study were tow fold; 1-dimensional column experiments for the changes in the gas saturation and contaminant removal during sparging, and 2-dimensional box model experiment for the changes in the size of zone of influence and contaminant removal. An anionic surfactant (SDBS, sodium dodecylbenzene sulfonate) was used to control surface tension of water. Fluorescein sodium salt was used as a representative of watersoluble contaminants, for its fluorescence which is easy to detect when it disappears due to oxidative degradation. Three different gases (air, high-concentration ozone gas, and low-concentration ozone gas) were used for the sparging of 1-D column experiment, while two gases (air and low-concentration ozone gas) were used for 2-D box model experiment. When SEOS was performed for the column and box model, the air saturation and the zone of influence were improved significantly compared to air sparging without surface tension suppression, resulted in effective removal of the contaminant. Based on the experiments observations conducted in this study, SEOS was found to maintain the advantages of SEAS with further capability of oxidative degradation of non-volatile contaminants.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권4호
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• pp.15-21
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• 2015

Anaerobic biodegradation of diesel with coexisting heavy metals (Pb) was monitored in batch mode. Two different groups of the indigenous bacteria from a site contaminated with diesel and lead were used in this research: the first group was composed of a single species and the second group was composed of several species. The effect of heavy metals on the microbial population was monitored and confirmed the biodegradation mechanism in each combined contaminant. Growth of the microorganisms in 21 days was observed Diesel > Diesel + Pb > Diesel + Cu > Diesel + Pb + Cu > Diesel + Cr > Diesel + Pb + Cr. Indigenous microorganisms showed the adaptation in the Pb contaminate. Interactive toxic effect using AMES test observed larger synergistic effect than antagonistic in Diesel + Cr and Diesel + Pb + Cr. Therefore, the main effects of diesel biodegradation in the present of heavy metals are likely to exist other factors as well as toxic of heavy metals. This is a necessary part of the future studies.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.22-27
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• 2006

This paper describes the development of the stream-tube based dispersion model for modeling contaminant transport in open channels. The operator-splitting technique is employed to separate the 2D contaminant transport equation into the pure advection and pure dispersion equations. Then the total variation diminishing (TVD) schemes are combined with the second-order Lax-Wendroff and third-order QUICKEST explicit finite difference schemes respectively to solve the pure advection equation in order to prevent the occurrence of numerical oscillations. Due to various limiters owning different features, the numerical tests for 1D pure advection and 2D dispersion are conducted to evaluate the performance of different TVD schemes firstly, then the TVD schemes are applied to experimental data for simulating the 2D mixing in a straight trapezoidal channel to test the model capability. Both the numerical tests and model application show that the TVD schemes are very competent for solving the advection-dominated transport problems.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.116-119
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• 2000

There has been a steady increase in geoenvironmental engineering projects where geotechnical engineering has been combined with environmental concerns. Many of these projects involve some investigation on contaminant and leachate flume in the ground and landfill. In this study, investigation and assesment on soil and groundwater around the waste landfill was carried out. Many techniques such as drilling and sampling method were applied. As a result of this study, the concentration of soil and groundwater were investigated and analysed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.471-474
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• 2003

There has been a steady increase in geoenvironmental engineering projects where geotechnical engineering has been combined with environmental concerns. This study investigate on contaminant around unsanitary landfill situated in urban area and was carried out to evaluate the geoenvironmental characteristics of this site. As a result of this study, groundwater and soil around this landfill site was evaluated for analysis of physical and chemical properties.

• 한국의학물리학회지:의학물리
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• 제6권2호
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• pp.41-50
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• 1995

암치료용 방사선 (15 MV의 에너지를 갖는 광자선) 속에 있는 흡수선량과 불순전자 또는 산란 광자에 관한 분포를 광자선 면적 크기에 따른 변화와 광자선 면적을 반만 차폐시킨 선속에 대하여 연구 조사하였다. 광자선의 에너지를 15MV로 주어질때 광자선 최대 흡수깊이 $d^{max}$ 값은 광자선의 면적을 증가시키면 시킬수록(5$\times$5 에서 30$\times$30$\textrm{cm}^2$)d$_{max}$ 값은 감소된다. 이는 광자선 즉 방사선을 발생시키는 가속기 기계 속에 있는 여러 부품 (flattening filter, collimator jaws, tray holder,……)과 상호작용하여 형성된 불순전자로 인하여 d$_{max}$ 값이 표피쪽으로 이동되어 buildup 영역에 높은 선량흡수를 갖게 된다. 최대 흡수깊이 값을 계산할 때 이러한 현상을 고려하지 않으면 그릇된 data 값을 갖는다. 대부분의 불순 전자는 광자선 중심에 주로 분포하며 그 진행거리는 30.0mm 이하의 짧은 거리를 갖는다. 이 불순전자가 30.0mm이내(즉 buidup 영역)에 전부 흡수되므로 buidup 영역은 높은 선량흡수를 갖게되어 해를 주게된다. 그러므로 이러한 불순전자를 제거시키므로서 buidup 영역에 낮은 선량 흡수를 갖을 뿐 아니라 d$_{max}$ 값도 역시 깊은 곳까지 이동시켜 치료에 효과적인 방법 이 창출된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.183-185
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• 2004

In this study, the combined electrokinetic and ultrasonic remediation technique, ultrasonically enhanced electrokinetic technique, was studied for the removal of heavy metal and organic substance in contaminated soils. The electrokinetic technique has been applied to remove mainly the heavy metal and the ultrasonic technique has been to remove mainly organic substance in contaminated soil. The laboratory soil flushing tests combined electrokinetic and ultrasonic technique were conducted using specially designed and fabricated devices to determine the effect of these both techniques. A series of laboratory experiments involving the simple, electrokinetic, ultrasonic, and electrokinetic & ultrasonic flushing test were carried out. A soil admixed with sand and kaolin was used as a test specimen, and Pb and ethylene glycol were used as contaminants of heavy metal and organic substance. An increase in out flow, permeability and contaminant removal rate was observed in electrokinetic and ultrasonic flushing tests. Some practical implications of these results are discussed in terms of technical feasibility of in situ implementation of electrokinetic ultrasonic remediation technique.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.258-261
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• 2004

In this study, the combined electrokinetic and ultrasonic remediation technique onto simple soil flushing was studied for the enhancement of water and liquid flows and the removal of contaminants in contaminated soils. The ultrasonic technique has been used to increase liquid flow and remove pollutants in contaminated soil. The laboratory soil flushing tests combined electrokinetic and ultrasonic technique were conducted using specially designed and fabricated devices to determine the effect of these both techniques. A series of laboratory permeability experiments involving the simple, electrokinetic, ultrasonic, and electrokinetic & ultrasonic flushing test were carried out. A soil admixed with sand and kaolin was used as a test specimen, and Pb and ethylene glycol were used as contaminants. An increase in out flow, permeability and contaminant removal rate was observed in electrokinetic and ultrasonic flushing tests.

• 상하수도학회지
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• 제20권4호
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• pp.627-635
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• 2006

Combined sewer overflow (CSOs) is a primary diffuse source degrading water quality of urban streams. In this study, CSOs caused by 5 different rainfall events at an urban watershed located in Daejeon city were monitored for the indicator microorganism concentrations. Event mean concentration (EMC) of the indicator microorganisms were: total coliform = $2.46{\times}10^6CFU/100mL$; fecal coliform = $1.01{\times}10^6CFU/100mL$; E.coli = $5.20{\times}10^5CFU/100mL$; and Fecal Streptococci = $6.08{\times}10^5CFU/100mL$. In addition, coliform concentrations were well correlated with suspended solid concentrations and the first flush effects were identified. Settling tests were carried out to estimate removal rate of indicator organisms by sedimentation from CSOs. As microorganisms are discharged in association with suspended solid, ten minutes of settlement can lower 44% of indicator microorganism leading.

• 환경정책연구
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• 제5권2호
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• pp.49-67
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• 2006

선진 외국에서 먹는물 중 방사성물질의 관리동향에 대한 고찰은 다음과 같다. 미국은 1974년 안전한 음용수법에 규제안을 설정한 후, 30년 이상 개정하여 현재 우라늄 MCL은 $30{\mu}g/L$, 라돈 AMCL 4,000pCi/L 또는 MCL 300pCi/L, 라듐-226과 라듐-228의 합 5pCi/L로 설정하여 관리하고 있다. 캐나다는 우라늄을 $20{\mu}g/L$로 잠정적으로 설정하였다. WHO는 2004년 9월 우라늄과 라돈의 가이드라인을 각각 $15{\mu}g/L$과 100Bq/L로 개정 하였다. 선진 외국은 먹는물 중 방사성물질에 대하여 수십년간 연구조사결과를 토대로 수질기준을 정하였고, 지속적으로 개선 및 보완을 하여 관리하고 있음을 알 수 있었다.