• Environmental Engineering Research
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• 제13권2호
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• pp.73-78
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• 2008

For a given soil-contaminated site, a level of soil contamination is characterized and decisions on risk may be made from the risk assessment. The study evaluated critical design factors for the determination of sample size in the sampling design plan and the assessment of soil contaminant- leaching to groundwater. Two variables, the minimum relative detectable difference (T) and coefficient of variation (CV) were evaluated for the sample size determination. The minimum number of samples can be appropriately determined by CV under a T value greater than or equal to 0.2. Soil-contaminant leaching to groundwater was evaluated by using the Soil Screening Level equation of U.S. Environmental Protection Agency and the Risk Based Screening Level equation of American Society for Testing and Materials, with the same input parameters. The groundwater concentrations estimated from soil contaminant concentrations were significantly affected by the Darcy velocity of groundwater and the organic content of soil.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.115-119
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• 2001

Contaminant retardation factor is derived from the colloidal and contaminant transport equations for a four-phase porous medium: an aqueous phase, two mobile colloidal phases, and a solid matrix. It is assumed that the contaminant sorption to solid matrix and colloidal particles and the colloidal deposition on solid matrix follow the linear isotherms. The behavior of the contaminant retardation factor in response to the change of model parameters is examined employing the experimental data of Magee et al. (1991) and Jenkins and Lion (1993). In the four-phase system, the contaminant retardation factor is determined by both the contaminant association with solid matrix and colloidal particles and the colloidal deposition on solid matrix. The contaminant mobility is enhanced when the affinity of contaminants to mobile colloids increases. In addition, as the affinity of colloids to solid matrix decreases, the contaminant mobility increases.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.327-330
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• 2002

In this study, analyses of contaminant transport are peformed to evaluate the diffusion effect of A sewage tunnel. First, Crank's analytical method is used to measure the concentration change of contaminant with time and space. Two dimensional numerical analysis is performed to measure concentration distribution of contaminant. Both methods show that the diffusion effect is little even after 500 years. This means that when flow converges into the tunnel, the environmental effect of contaminant in tunnel is not serious because there is no advection occurs.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 사용종료 매립지의 안정화 에 관한 국제 세미나
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• pp.1-40
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• 1996

In order to determine the proper treatment of the finished landfill, it is important to predict the trend and stability of the major sources of contaminant in the landfill. In this paper the fate of contaminant sources in the landfill is studied from various literatures by grouping the contaminants into waste, leachate, and landfill gas. One example site referred is Nanji landfill which is one of the representative finished landfills in our country and the trend of contaminant sources in this landfill at current stage is discussed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.189-196
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• 2003

Soil-cement column is often used as a contaminant barrier. This study presents the results of experimental study performed to investigate the changes of properties of soil-cement column under the attack of acids. Sulfuric nitric, and ascetic acid were used as contaminants. Specimen were made of clayey and sandy soils with addition of cement and water Permeability of soil-cement decreased with time during permeability test. When significant amount of acid percolated the specimen, permeability increased and compressive strength decreased due to the dissolution and leaching of cement and its chemical reaction compounds. Sulfuric and nitric acid were more effective than ascetic acid in deteriorating soil-cement column. Amount of acid required to lower the pH of soil cement below 12 was calculated from the results of permeability tests. This leads to a conclusion that, under the conditions employed in this study, the chemical stability of soil-cement column could be maintained against acid attack for longer than generally accepted lifetime of contaminant barriers.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.37-40
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• 2000

Acoustically enhanced soil flushing method is a newly developed in-situ remediation technique. However, there has not been an analytical method that can be used to evaluate the effectiveness of ultrasonic wave under different conditions. This study was undertaken to investigate the degree of enhancement in contaminant removal due to ultrasonic energy on the soil flushing method. The test conditions included different levels of ultrasonic power and hydraulic gradient. The test soils were Ottawa sand, a fine aggregate, and a natural soil, and the surrogate contaminant was a Crisco Vegetable Oil. The test results showed that sonication could increase contaminant removal significantly. Increasing sonication power increased pollutant removal. The faster the flow is, the smaller the degree of enhancement will be. The pollutants in dense soils are more difficult to be removed than in loose soils.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.8-12
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• 2003

The centrifuge test result on capped sediment was compared to the advection- dispersion equation proposed for one layered to predict contaminant transport parameters. The fitted contaminant transport parameters for the centrifuge test results were one to three orders of magnitude greater than the estimated parameters from the advection-dispersion equation. This indicates that the centrifuge model over estimated the contaminant transport phenomena. Thus, the centrifuge provides a non-conservative approach to modeling contaminant transport. It should be also noted that the advection-dispersion equation used in this study is a one layered model. Two layered modeling approaches are more appropriate for modeling this data since there are two layers with different partitioning coefficients. Further research is required to model the centrifuge test using two-layered advection-dispersion models.

• 한국지반신소재학회논문집
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• 제5권2호
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• pp.1-8
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• 2006

오염토양의 현장정화에 있어서 지반 및 오염물질의 물성치는 정화에 소요되는 시간과 함께 매우 중요한 고려사항이다. Gabr 등(1996)은 연직배수재가 설치된 오염지반에서 시 공간적 변화에 따른 초기오염농도에 대한 오염농도비($C/C_0$)를 구하는 식을 유도하였다. 본 연구에서는 Gabr 등이 유도한 식의 전산모형 FLUSH1을 이용하여 오염지반 흙의 유효입경, 간극률, 형상계수, 밀도, 지반의 온도와 오염물질의 단위중량 및 점성계수가 오염정화에 미치는 영향을 알아보기 위하여 시 공간적 변화에 따른 오염농도비($C/C_0$)를 분석 하였다. 분석결과 연직배수재가 설치된 오염지반에서 정화에 크게 영향을 미치는 인자는 오염지반 흙입자의 유효입경인 것으로 나타났으며, 그 다음으로 오염물질의 점성, 오염지반 흙의 간극율, 형상계수, 지반의 온도, 오염물질의 단위중량, 흙의 밀도 순으로 분석되었다. 오염지반 흙의 밀도는 오염정화에 미치는 영향이 아주 작은 것으로 나타났다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.355-360
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• 2005

The properties of contaminants, contaminated soil, and the elapsed time are important factors to in-situ soil remediation. Gabr et. al. (1996) derived the solution equation of contaminant concentration ratio as initial one $(C/C_0)$ with time and spatial changes in contaminated area with vertical drains. The contaminant concentration ratio $(C/C_0)$ is analyzed with time and spatial changes as varying the effective diameter, porosity, shape factor, density of contaminated soil and temperature in ground and unit weight, viscosity of contaminants by using FLUSH1 model. Results from numerical analysis indicate that the most important factor to the in-situ soil remediation using vertical drains is the effective diameter of contaminated soil. It also shows that the viscosity of contaminants, porosity of soil, shape of soil, temperature in ground, unit weight of contaminants are, in order, affected to the soil remediation but density of soil is insignificant to the soil remediation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.401-406
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• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.