• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.21-24
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• 1997

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.02a
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• pp.5-13
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• 2001

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.40-47
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• 2009

Coinjection of alcohol and air or alcohol flooding only were evaluated with 3-D soil tank for removal of nonaqueous phase liquid (NAPL) contaminant from soil. 70%-ethanol and 40%-isopropanol were used for non-NAPL-swelling alcohol and NAPL-swelling alcohol, respectively. 729 ml-benzene was placed in the 37 liter soil tank. Alcohols were respectively injected from the injection well placed near the bottom of the tank and mobilized free phase NAPL and aqueous phases were then recovered from the extraction well placed in the upper part of the soil tank. Approximately 50% of removed NAPLs were free-phase in all experiments. The results were completely different to the previous soil column experiment results and also implied that alcohol properties did not affect the NAPL removal efficiency in the 3-D soil tank experiment. Air was also co-injected with alcohol to evaluate co-injection effects on NAPL removal. Enhanced NAPL removal effect of co-injection of 70%-ethanol and air was also found even in the 3-D soil tank evaluation. However, co-injection effect of 40%-iso-propanol and air was less apparent. This study determined that the most important parameter governing alcohol flooding for NAPL removal would be extraction capacity to recover NAPL and aqueous phase flowing in the soil. More researches are required for improving recovery efficiency of extraction well in real soil contamination conditions.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1095-1101
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• 2008

Nonaqueous phase liquids (NAPL) are the continuous source for soil and groundwater contamination. The first objective of the study was to verify the effect of co-injection of cosolvent and air on NAPL removal from soil-column system. The second objective of the study was to investigate the effect of alcohol-partitioning property on the NAPL removal by the co-injection process of cosolvent and air. Enhanced removal of benzene-NAPL by the co-injection process of ethanol and air was also verified within the soilcolumn system. However, the co-injection process of Tert-butanol (TBA) and air showed no enhancement of benzene-NAPL removal. This study found that the viscous pressure of TBA was so higher than the capillary pressure and TBA easily displaced the benzene-NAPL and air present in soil pores. Air of the coinjection process did not work for NAPL removal but hindered NAPL mobilization. NAPL partitioning property and viscous pressure of cosovlent should be considered for application of the co-injection process of cosolvent and air.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.1-9
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• 2008

This study examined the effect of an electrokinetic-flushing remediation for a soil of a high permeability. The soil was sampled from the site around a research atomic reactor which had high hydro-conductivities due to a high content of sand in the soil. The flow rate of the washing reagent was fast at the beginning but it was reduced as time lapsed. In the case of using citric acid as a washing reagent, the flow rate was fastest, 78.7 ml/day. The removal efficiencies of $Co^{2+}$ and $Cs^+$ from a soil cell with acetic acid were the highest, which were 95.2% and 84.2% respectively. The soil waste-solution volume generated from the electrokinetic remediation was reduced to about 1/20 of that from the soil washing remediation. Meanwhile, the electrokinetic-flushing method enhanced the removal efficiencies of $Co^{2+}$ and $Cs^+$ from the soil by about 6% and 2% respectively, compared to those by the electrokinetic method. Consequently, it was found that the electrokinetic-flushing method was more effective for the remediation of a soil with a high permeability.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.99-102
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• 2002

전기분해에 의한 부상현상을 이용하여 토양세정 후 발생되는 유출수 중의 유수를 분리하기 위한 적정 운전조건에 관하여 고찰하였다. 전압에 의한 유수분리 효율을 관찰한 결과, 전기분해 1시간 후 3V의 전압만으로도 88% 정도의 제거율을 나타내었으며 6V 이상의 전압에서는 90% 정도로 거의 비슷한 제거율을 나타내어 대부분의 에멀젼이 분리됨을 확인할 수 있었다. 동일조건에서는 전기분해 시간이 경과될 수록 분리효율이 향상되었으며, 전극 간격이 넓어질수록 같은 효율을 얻기 위해 소요되는 전압의 크기가 커짐을 알 수 있었다. 전기분해 시 양극에서는 OH$^{-}$의 방전으로 발생되는 산소에 의해 산화반응이 일어나며, 음극에서는 H$^{+}$가 방전되어 발생되는 수소에 의해 환원반응이 일어나며 미세한 기포가 형성된다. 유분의 부상분리 현상은 유분의 (-)charge와 전기분해에 의해서 발생되는 양이온의 결합으로 인한 중화반응 및 음극에서 발생되는 미세 수소기포로 인만 부상분리가 대부분을 차지하며, 전압 및 전기분해 시간이 증가하고 전극 간격이 좁을수록 음극에서 발생되는 미세기포의 양이 증가되어 부상효과가 크게 나타나는 것으로 판단된다. 전극 종류는 구리 > 알루미늄 > 철 > 티타늄 순으로 효율을 나타내었으며, 이는 양극으로 사용된 이러한 금속들의 전기전도도 차이에 의해 일어나는 현상으로 판단된다

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.53-60
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• 1997

A series of batch and lab-scale pilot tests were conducted to optimize the design parameters for the application of soil washing techniques to the soil contaminated by heavy metals. Cu, Pb, and Zn were selected as target heavy metals. The concentrations of Cu, Pb, and Zn were 500mg/kg dry soil, 1, 000mg/kg dry soil, and 500mg/kg dry soil, respectively. Citric acid and oxalic acid were used for the extractants. In the batch tests, the extraction efficiencies for Cu, Pb, and Zn were 79%, 72%, 72%, respectively. The proper extractant concentration and dilution ratio(weight/volume) for Cu and Pb were turned to be citric acid 50mM and 1:5, respectively. The extraction efficiencies were enhanced with the addition of 1~2% OA-5 or SDS. From pilot scale tests for Pb, first stage and second stage of soil washing resulted in the extraction efficiency of 59% and 78%, respectively.

• Clean Technology
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• v.23 no.3
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• pp.302-307
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• 2017

This study was conducted to evaluate the feasibility of in situ soil flushing for TPH-contaminated soil remediation with column test. The soil texture of the soil was sand and the initial TPH concentration was $9,369mg\; kg^{-1}$. 0.1% Tween-80 was selected as surfactant solution. And the acrylic and the glass syringe columns were used as reactors. In the acrylic column test, 35% of the initial TPH was removed in 1 PV of flushing and approximately 40% in 5 PV and finally 7 PV showed about 60%. The glass column test showed 3 ~ 12% higher removal efficiency than that of acrylic test until 5 PV of flushing. However, there was no difference in TPH removal efficiency when 7 PV of surfactant was finally flushed. Both of alum only and alum+polymer mixed surfactants showed also the best coagulation efficiency in $150mg\;L^{-1}$ of concentraion. When Tween 80 was newly dissolved in 0.1% to the recovered solution after the coagulation treatment, the removal efficiency was increased from 32.0% to 41.0% in comparison to the new 0.1% Tween 80 solution without reuse by coagulation treatment.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.79-84
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• 2002

The optimal operation conditions, including voltage applied, reaction time, distance between electrodes. and electrode material. were investigated for the treatment of soil flushing effluent using electrofloatation. When 3V was applied for 1 hour, 88% oil-water separation efficiency was achieved. In case of 6V and above, 90% efficiencies were achieved. As reaction time and distance between electrodes were longer, separation efficiencies were higher and lower, respectively. Separation efficiencies for different anode materials were copper > aluminum > iron > titanium. It might result from the differences of their electrical conductivities.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.56-60
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• 2003

The optimal operation conditions of electrofloatation for oil-water separation of soil flushing effluent including electrolyte and pH were investigated. The reactor (200 ${\times}$ 10 ${\times}$ 15 cm) for the experiment was constructed by using acrylic plate. Diesel concentration was 1,000 mg/L in the 1 % mixed surfactant solution ($POE_5$: $POE_{14}$ 1: 1). Titanium coated electrode was used as cathode and stainless steel electrode as anode. Reaction time was 62 minutes (reaction time: 60 min., flotation time: 2 min.) and voltage was 6 V. The separation efficiency of electrofloatation was improved to 40% by electrolyte addition. Furthermore, NaCl (1N) added as electrolyte was showed enhanced efficiency compared to NaOH (1N). While, the effect of both NaCl and NaOH was sequentially increased in the range of 0.2∼1.0% (0.02∼0.1 M). The equilibrium time was found as 20 min. in the range of 0.4∼1.0% (0.04∼0.1M) for both of them.