• Title/Summary/Keyword: Soil decontamination

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The Characteristics of Electrokinetic Remediation for Unsaturated Soil (불포화토의 동전기정화 특성에 관한 실험적 연구)

  • 김병일;김익현;한상재;김수삼
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.641-646
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    • 2003
  • In this study, a series of electrokinetic(EK) remediation experiments are carried out under the different degree of saturation for contaminated soil with lead. for constant electrical potential, the final current of all the sample represents the similarity to steady-state value of 5∼7mA. Under conditions of all the degree of saturation the anode reservoir becomes acidic(pH as low as 3) while the cathode reservoir is basic(pH as high as 12). But pH changes in the sample is a little and decontamination efficiency is the low.

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The Status and Prospect of Decommissioning Technology Development at KAERI (한국원자력연구원의 해체기술 개발 현황 및 향후 전망)

  • Moon, Jeikwon;Kim, Seonbyung;Choi, Wangkyu;Choi, Byungseon;Chung, Dongyong;Seo, Bumkyoung
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.2
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    • pp.139-165
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    • 2019
  • The current status and prospect of decommissioning technology development at KAERI are reviewed here. Specifically, this review focuses on four key technologies: decontamination, remote dismantling, decommissioning waste treatments, and site remediation. The decontamination technologies described are component decontamination and system decontamination. A cutting method and a remote handling method together with a decommissioning simulation are described as remote dismantling technologies. Although there are various types of radioactive waste generated by decommissioning activities, this review focuses on the major types of waste, such as metal waste, concrete waste, and soil waste together with certain special types, such as high-level and high-salt liquid waste, organic mixed waste, and uranium complex waste, which are known to be difficult to treat. Finally, in a site remediation technology review, a measurement and safety evaluation related to site reuse and a site remediation technique are described.

Improved Treatment Technique for the Reuse of Waste Solution Generated from a Electrokinetic Decontamination System (동전기제염장치에서 발생한 폐액의 재사용을 위한 개선된 처리기술)

  • Kim, Wan-Suk;Kim, Seung-Soo;Kim, Gye-Nam;Park, Uk-Ryang;Moon, Jei-Kwon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.1
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    • pp.1-6
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    • 2014
  • A large amount of acidic waste solution is generated from the practical electrokinetic decontamination equipments for the remediation of soil contaminated with uranium. After filtration of uranium hydroxides formed by adding CaO into the waste solution, the filtrate was recycled in order to reduce the volume of waste solution. However, when the filtrate was used in an electrokinetic equipment, the low permeability of the filtrate from anode cell to cathode cell due to a high concentration of calcium made several problems such as the weakening of a fabric tamis, the corrosion of electric wire and the adhension of metallic oxides to the surface of cathode electrode. To solve these problems, sulfuric acid was added into the filtrate and calcium in the solution was removed as $CaSO_4$ precipitate. A decontamination test using a small electrokinetic equipment for 20 days indicated that Ca-removed waste solution decreased uranium concentration of the waste soil to 0.35 Bq/g, which is a similar to a decontamination result obtained by distilled water.

EVALUATION OF FERROCYANIDE ANION EXCHANGE RESINS REGARDING THE UPTAKE OF Cs+ IONS AND THEIR REGENERATION

  • Won, Hui-Jun;Moon, Jei-Kwon;Jung, Chong-Hun;Chung, Won-Yang
    • Nuclear Engineering and Technology
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    • v.40 no.6
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    • pp.489-496
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    • 2008
  • Ferrocyanide-anion exchange resin was prepared and the prepared ion exchange resins were tested on the ability to uptake $Cs^+$ ion. The prepared ion exchange resins were resin-KCoFC, resin-KNiFC, and resin-KCuFC. The three tested ion exchange resins showed ion exchange selectivity on the $Cs^+$ ion of the surrogate soil decontamination solution, and resin-KCoFC showed the best $Cs^+$ ion uptake capability among the tested ion exchange resins. The ion exchange behaviors were explained well by the modified Dubinin-Polanyi equation. A regeneration feasibility study of the spent ion exchange resins was also performed by the successive application of hydrogen peroxide and hydrazine. The desorption of the $Cs^+$ ion from the ion exchange resin satisfied the electroneutrality condition in the oxidation step; the desorption of the $Fe^{2+}$ ion in the reduction step could also be reduced by adding the $K^+$ ion.

Methods of Recycling Soil Washing Wastewater for Volume Reduction (토양세척폐액 부피감소를 위한 재생방법 연구)

  • 김계남;원휘준;오원진
    • Journal of Soil and Groundwater Environment
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    • v.8 no.1
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    • pp.17-26
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    • 2003
  • The sorption experiment of cobalt was performed after the TRIGA soil was intentionally contaminated with cobalt was found that the sorption equilibrium coeficiency of soil decontamination was high when the ratio of soil mass to the volume of citric acid becomes 1:5 The TRIGA soil contaminated with 0.01 M, 0.001 M, and 0.0001 M of cobalt solution were decontaiminated with 0.01 M citric acid. The cobalt concentrtion in the wastewater were measured to be correspondingly 36.0, 14.0, 1.5 ppm. The results of wastewater recycling experiment by chemical precipitation method revealed that corresponding cobalt removal efficiency were 97% 88%. It was shown that the removal efficiency decreases as the cobalt concentration in the wastewater decreases. During the decontamination experiment, a lot of NaOH had to be added, and the volume of final solid waste reached almost 10% of that of the contaminated soil. The result of wastewater recyling experiment by ion exchange resin meted rethod revealed that to more the strong acid resins are used, the higher the cobalt removal efficiency becomes and the cobalt removal efficiency becomes and the lower the pH of recycling wastewater become. In order to obtain more than 95% removal efficiency, more than 0.625 g of strong acid resin was necessary in each of 3 experiments. There was an unexpected problem that a lot of strong acid resin waste was produced which amounts to 9.2% (volume) of the contaminated soil.

Remediation of Contaminated Soil with Organic Contaminants using Microemulsion (마이크로이멀젼을 이용한 유기오염물로 오염된 지반의 정화)

  • Park, Ki-Hong;Kwon, Oh-Jung;Park, Jun-Boum
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.597-604
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    • 2003
  • In the soil washing process, the contaminants are usually removed by abrasion from soil particles using mechanical energy and water However, organic contaminants with low water solubility like polycyclic aromatic hydrocarbons (PAH) are remained on soil particles. Previous studies have shown that surfactant possessing amphipathic activity enhances the solubility of organic materials. For this reason solutions with surfactants have been used to improve removal of organic contaminants on soil washing process. But, in this manner, many problems were found like complete loss of surfactants and additional contamination by surfactant. The remediation method using microemulsion has been introduced to overcome these disadvantages. In this case, surfactants are recycled by phase separation of microemulsion after remediation. In microemulsion process, the surfactant will be recycled by phase separation of the microemulsion into a surfactant-rich aqueous phase and an oil phase after extraction. That is why remediation concept applying microemulsion as washing media has been Introduced. Suitable microemulsion have to be used in order to have the chance of refilling the soil after decontamination and to avoid any risk due to toxicity. The purpose of this research is to evaluate effect of microemulsion to remediation of contaminated soil. We performed test with various organic contaminants like Pyrene and BTEX, also compared efficiency of remediation in microemulsion process with soil washing

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A study on the removal of heavy metals from soils using electrokinetic soil processing and ion exchange membrane (전기장과 이온교환막을 이용한 토양에서의 중금속 제거에 대한 연구)

  • 김순오
    • Economic and Environmental Geology
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    • v.32 no.1
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    • pp.43-51
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    • 1999
  • In order to remediate hazardous waste site, a process of electrokinetically purging chemicals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes that habe igh removal efficiency and time-effectiveness in low-permeability soils such as clay. Being combined with several mechanisms-electromigration, elec troosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. The objectives of this study are; 1) the exploration of the feasibility of electrokinetic soil processing on the removal of heavy metals, 2) the investigation of applicability to the tailing-soils in aban doned mining area, 3) the examination of effects of soil pH and conductivity on the transport phenomena of elements in soils, and 4) the investigation of the applicability of the ionexchange membrance to the efficient collection of heavy metals removed from contaminated soils. With the result of this study, it is suggested that the removal efficiency is significantly influenced by applied voltage & current, type of purging solutions, soil pH, permeability and zeta potentials of soil. Although further study should be needed, it is possible to collect removed heavy metals with ion-exchange membrance in cathode compartment.

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pH Variation In Soils Considering Buffer Capacity during Electrokinetic Extraction (Electrokinetic정화시 토질의 완충능을 고려한 시료내의 pH변화)

  • 오승록;한상재;김수삼;조성호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.585-590
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    • 2001
  • Physicochemical phenomena in soils are dependent upon pH when using electrokinetic extraction for the contaminants removal especially for heavy metals. pH variation in soils is affected on H$\^$+/ and OH ̄ ions produced by electrolysis reaction and buffer capacity of soil. High amount of heavy metals are retained in the soils if the soil buffer capacity remains high enough to resist a change in pH. Therefore, accurate pH estimation of soil is important in the application of electrokinetic mechanism for decontamination and understanding of subsurface physicochemical characteristics is also required as well as considering buffer capacity for the enhanced methods application. For these, buffer capacity and pH distribution were measured for the four soils, and also compared with modeling results. The results of buffer modeling were good agreement with experimental data. It is showed that four soils were effected by buffer capacity

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Evaluation of Separation Distance from the Temporary Storage Facility for Decontamination Waste to Ensure Public Radiological Safety after Fukushima Nuclear Power Plant Accident (후쿠시마 원전 사고 이후 일반인의 방사선학적 안전성 확보를 위한 제염폐기물 임시저장시설 이격거리 평가)

  • Kim, Min Jun;Go, A Ra;Kim, Kwang Pyo
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.14 no.3
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    • pp.201-209
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    • 2016
  • The object of this study was to evaluate the separation distance from a temporary storage facility satisfying the dose criteria. The calculation of ambient dose rates took into account cover soil thickness, facility size, and facility type by using MCNPX code. Shielding effects of cover soil were 68.9%, 96.9% and 99.7% at 10 cm, 30 cm and 50 cm respectively. The on-ground type of storage facility had the highest ambient dose rate, followed by the semi-ground type and the underground type. The ambient dose rate did not vary with facility size (except $5{\times}5{\times}2m\;size$) due to the self-shielding of decontamination waste in temporary storage. The separation distances without cover soil for a $50{\times}50{\times}2m\;size$ facility were evaluated as 14 m (minimum radioactivity concentration), 33 m (most probably radioactivity concentration), and 57 m (maximum radioactivity concentration) for on-ground storage type, 9 m, 24 m, and 45 m for semi-underground storage type, and 6 m, 16 m, and 31 m for underground storage type.