• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.91-101
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• 1996

In recent years, phytoremediation, the use of plants to detoxify hydrocarbons, has been a promising new area of research, particularly in situ cleanup of large volumes of slightly contaminated soils. There is increasing need for a mathematical model that can be used as a predictive tool prior to actual field implementation of such a relatively new technique. Although a number of models exist for solute-plant interaction in the vegetated zone of soil, most of them have focused on ionic nutrients and some metals. In this study, we developed a mathematical model for simulation of bioremediation of hydrocarbons in soil, associated with plant root systems. The proposed model includes root interactions with soil-water and hydrocarbons in time and space, as well as advective and dispersive transport in unsaturated soil. The developed model considers gas phase diffusion and liquid-gas mass exchanges. For simulation of temporal and spatial changes in root behavior on soil-water and with hydrocarbons, time-specific distribution of root quantity through soil was incorporated into the simulation model. Hydrocarbon absorption and subsequent uptake into roots with water were simulated with empirical equations. In addition, microbial activity in the rhizosphere, a zone of unique interaction between roots and soil microorganisms, was modeled using a biofilm theory. This mathematical model for understanding and predicting fate and transport of compound in plant-aided remediation will assist effective application of plant-aided remediation to field contamination.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.3-12
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• 1997

Phytoremediation, using plants to remediate toxic organic and inorganic pollutants in contaminated soils, is an emerging technology for environmental cleanup. Three strategies of this technology are applicable to the remediation of toxic heavy metals, radionuclides, and toxic organic pollutants: They are (1) phytoextraction, in which plants anumulate the contaminants and are harvested for the downstream processing; (2) phytodegradation, in which plant-released enzymes or plant-associated microorganisms convert toxic pollutants into non-toxic materials; and (3) phytostabilization, in which toxic pollutants are precipitated from solution or absorbed in either the plant tissue or the soil matrix. Phytoremediation is more effective and less expensive than other current treatment technologies.

• Journal of Environmental Policy
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• v.4 no.1
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• pp.39-67
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• 2005

In order to properly define the terms such as soil, soil contamination, soil contamination site and remediation, which are the key terms under the Soil Environment Conservation Act(SECA) in Korea, we analyzed the legal definitions of the similar key words in legislations of the developed western countries. The selected countries were the United States of America, the United Kingdom, the Netherlands, Germany, and Denmark. The legal definitions of these keywords were very much diversified due to different levels of soil contamination, as well as different industrial, social, and legal backgrounds in each country. However, fair suggestions for definitions of the key terms in SECA were derived from the comparative analyses of these countries. First and foremost, SECA should provide a definition of 'soil' which includes a concept of the natural soil layer produced from soil mineralization processes. Groundwater and sublayer of the groundwater would. be excluded in the boundary of the soil with regards to the Groundwater Act of Korea. Definition of 'soil contamination' of SECA should include a concept of risk assessment(soil contaminants, pathway, and receptors), purpose of land use, and the acquired limitation levels of soil contaminants. Soil contamination activity either industrial or anthropogenic in SECA article2-1, could be substituted for a concept of soil risk assessment. Definition of 'soil contamination site' could derive from amalgamating the concepts of i) soil contamination in conjunction with contaminants, ii) risk assessment, iii) a concept of land use, and iv) knowing limitation of contamination site designation. Definition of 'remediation of contaminated site' should include the objective, intention, action, methodology and limit of the remediation. These suggested definitions would increase the efficacy of soil environment conservation policies, which includes the survey of the potentially contaminated area, remediation, and removal of the site.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.8-17
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• 2006

Laboratory scale experiments were performed to investigate the removal efficiency of the in-situ chemical oxidation method and the air-sparging method for diesel contaminated soil and groundwater. Two kinds of diesel contaminated soils (TPH concentration : 2,401 mg/kg and 9,551 mg/kg) and groundwater sampled at Busan railroad station were used for the experiments. For batch experiments of chemical oxidation by using 50% hydrogen peroxide solution, TPH concentration of soil decreased to 18% and 15% of initial TPH concentration. For continuous column experiments, more than 70% of initial TPH in soil was removed by using soil flushing with 20% hydrogen peroxide solution, suggesting that most of diesel in soil reacted with hydrogen peroxide and degraded into $CO_2$ or $H_2O$ gases. Batch experiment for the air-sparging method with artificially contaminated groundwater (TPH concentration : 810 mg/L) was performed to evaluate the removal efficiency of the air-sparging method and TPH concentration of groundwater decreased to lower than 5 mg/L (waste water discharge tolerance limit) within 72 hours of air-sparging. For box experiment with diesel contaminated real soil and groundwater, the removal efficiency of air-sparging was very low because of the residual diesel phase existed in soil medium, suggesting that the air-sparging method should be applied to remediate groundwater after the free phase of diesel in soil medium was removed. For the last time, the in-situ box experiment for a unit process mixed the chemical oxidation process with the air-sparging process was performed to remove diesel from soil and groundwater at a time. Soil flushing with 20% hydrogen peroxide solution was applied to diesel contaminated soils in box, and subsequently contaminated groundwater was purified by the air-sparging method. With 23 L of 20% hydrogen peroxide solution and 2,160 L of air-sparging, TPH concentration of soil decreased from 9,551 mg/kg to 390 mg/kg and TPH concentration of groundwater reduced to lower than 5 mg/L. Results suggested that the combination process of the in-situ hydrogen peroxide flushing and the air-sparging has a great possibility to simultaneously remediate fuel contaminated soil and groundwater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.285-288
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• 2004

약 10,000 ing TPH/kg으로 오염시킨 디젤오염토양을 계면활성제로 세정한 결과 단일 계면활성제를 사용한 경우에는 POE12가 63%로 가장 세정효율이 우수하였다 단일 계면활성제를 혼합하여 세정한 결과 POE12와 SDS를 1%로 혼합하였을 때 10%의 세정증가효과가 있었으나, 다른 혼합액에서는 POE12를 단일로 사용한 경우와 유사하거나 오히려 감소하였다. 토양세정과 응집제를 사용하여 디젤오염토양을 정화할 경우 비이온 계면활성제인 POE12와 음이온 계면활성제인 SDS를 혼합하여 세정한 후 고분자 응집제인 A601p를 사용하여 세정액을 응집처리하는 것이 가장 효과적이었다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.194-195
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• 2005

방사선관리구역 내에서 발생되는 많은 양(발전소별 연간 약$100{\sim}700$개 정도)의 사용 후 공기정화 필터는 고체 폐기물 드럼의 단면적 보다 넓어 별도로 필터를 압축하거나 분해 작업 없이는 폐기물로 직접 처리가 곤란하다. 처리 시 많은 양의 분진이 발생하여 작업자의 내부피폭 가능성 및 많은 양의 고체 폐기물이 발생할 수 있는 잠재성이 있어 시료분석 결과 오염된 필터 내지는 바로 드럼 처리하여 내부 피폭 가능성을 미연에 방지하고 필터 프레임은 재사용을 유도하여 폐기물 저감화, 작업환경 개선 및 경제적인 이익을 창출할 수 있다. 영광 3발전소와 울진 3발전소의 경우 타 발전소에 비해 방사선관리구역 내 공기정화 처리기의 설치수량이 많아(약 700개/년) 공기정화필터가 매년 다수 발생되고 있으며, 이를 전량 드럼 처리 시 고체폐기물 드럼이 더 발생하게 되어 영구처분비용의 증가를 초래하게 된다. 발전소 전체적으로는 약 3,500개/년의 폐필터가 발생되고 있다. 이렇게 발생되는 공기정화필터의 프레임을 재사용함으로써 그 효과는 1) 알루미늄을 포함한 유리섬유를 드럼처리 시 고체방사성 폐기물드럼 생성량 감소 2) 프레임 재사용으로 인한 예산절감 효과 3) 폐필터 분해작업 시 분진에 의한 작업자 체내${\cdot}$외 피폭방지와 작업장 오염 확산 방지 및 환경 개선 4) 작업시간 단축 및 소요인력 감소 효과를 볼 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.1-8
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• 2006

The purpose of this study is to experimentally analysis the eletrokinetic phenomena and remediation characteristics developed during the application of electrokinetic remediation technique to unsaturated soils contaminated by heavy metals. In the laboratory a series of column tests are performed on degree of saturation for shooting range soil. The test results indicated that Pb is mainly removed under unsaturated conditions by electromigration within diffuse double layer, and if the initial containment concentration is below cation exchange capacity and equals to adsorption per unit soil solid weight, the remedial efficiency decreases with the decreasing of transport efficiency due to the changes in the degree of saturation in the electric gradient of 1V/cm.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.59-66
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• 2012

In this study, it was sampling from heavy metal-contaminated soil with the waste in railroad workshop. And, the pollution concentration and analysis of particle-size distribution were conducted to design efficient purification process that it was aimed at high contaminated area, low contaminated area and samples containing waste foundry sand. But, it was the other signs of general soil contamination, as construction waste of waste concrete and waste wood, waste foundry sand, incinerator ash, etc is overall buried on the grounds. Thus, the common heavy metal purification technology has not decreased the pollution. However, heavy-metal contamination was reduced by magnetic separation utilizing the magnetic component of the mixed waste.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.618-623
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• 2012

The significance of soil environment has been gradually increased because of petroleum leak accidents. Comparing with wastewater clean treatments and air pollutant controls, the soil purification requires a long-term process and it is very expensive. In this study, we analyzed the physicochemical properties of total petroleum hydrocarbon (TPH) contaminated in soil. This could be applied to deciding the source of petroleum when a soil contamination accident occurs.