• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.405-410
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• 2001

Bioremediation is a degradation process of existing organic contaminants in soils and groundwater by indigenous or inoculated microorganisms. This process can provide economical solution as well as safe and effective alternative in remediation technologies. However, it has been suggested that the rate of bioremediation process of organic contaminants by microorganisms can be limited by the concentration of nutrients and TEAs(Terminal Electron Accepters). In in-situ bioremediation, conventional pumping techniques have been used for supplying these additives. However, the injection of these additives is difficult in low permeable soils, and also hindered by preferential flow paths resulting from heterogeneities in high permeable ground. Therefore, the Injection of chemical additives is the most significant concern in in-situ bioremediation. Most recently, electrokinetic technique has been applied into the bioremediation and the injection characteristics under electrokinetics have not been examined in various soil types. Therefore, in this study, electrokinetic injection method is investigated in kaolinite and sand, and the concentration of ammonium(nutrients) and sulfate(TEAs) in soil is presented.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.15-24
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• 2002

Nowdays electrokinetic technique has been applied to supply nutrients and TEAs for in-situ bioremediation. However the Injection characteristics under electrical field have not been examined in various soil types. Therefore, The characteristics of electrokinetic injection into kaolinite and sand are investigated. During the 17 d of processing, There was a gradual increase in ammonium (nutrient) concentration from the anode compartment. However the ammonium concentration at the cathode increased beyond that at the anode in sand. A relatively constant profile of sulfate (TEA) was achieved specifically, the final sulfate concentration in each specimen were different. When EK injection technique is implemented in field, the most important consideration should be an assessment of the injection characteristics with respect to the soil types.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.351-354
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• 2002

In this study, variation of electrochemical parameters and characteristics of lead immobilization due to phosphoric acid injection in soil were studied during electrokinetic remediation of lead contaminated soil. TCLP result showed about 100% of soil was satisfied TCLP regulation criteria. And injected ion from cathode reservoir by ionmigration was proportionate to concentration of phosphoric acid and elapsed time. Therefore, when removal is infeasible or not cost-effective, in situ immobilization method would be more effective.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.310-313
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• 2003

The precipitation of heavy metals within the region of pH jump is inevitable in the conventional electrokinetic remediation technology. This study prevents the interest species from precipitating through the injection of flushing solutions in which HCl, acetic acid, citric acid, EDTA and SDS dissolved. The cumulative flow resulted from electroosmosis appear in order of Citric acid

• Analytical Science and Technology
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• v.9 no.1
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• pp.35-42
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• 1996

A rapid analytical method based on capillary electrophoresis is described for the determination of trace anions in high-purity chemicals which is used to prevent corrosion demage in nuclear power plants. Separations are carried out at 20kV using trimethylsilane-coated fused-silica capillary ($70cm{\times}50$ or $75{\mu}m$ i.d.) with the electrolyte of 5mM Chromate(pH=8). Detection was achieved using on-column indirect photometry at 254nm. The simultaneous analysis of inorganic anions, chloride, nitrate, sulfate, azide and phosphate was performed using methods of hydrodynamic(>1ppm) and / or electrokinetic(<1ppm) injection. The results of studies on the coexisting anions on analyte ions shows that peak responses of analyte in hydrodynamic injection is constant without effect of coexisting anions, but those of analysis in electrokinetic injection is strongly dependant upon the kind of coexisting anions and its ionic mobility. The analyte enrichment rate, hence peak response, is positive relationship with the resistance of the sample solution. Thus, appropriate measures, such as standard addition or internal standard technique, must be used to account for differences in conductance of standard and sample solutions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.20-23
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• 2000

The use of electrokinetic injection and transport for the distribution of an NAPLs-degrading microorganism in a sandy soil bed was studied. After the injection of the cell into cathode side of bed, an electric current was applied. The transport of cell though the sandy soil was achieved by electokinetics, mainly by electrophoresis, The pH control in electrode chamber plays un important role to achieve desirable cell transport because H$^{+}$ generated at anode is toxic or inhibits the transport of cells. Electokinetic distribution rate of bacterial cells changed depending on the applied electric current and pH. The degradation of diesel by electrokinetically transport cells were monitored.d.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.31-34
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• 2004

Feasibility of electrokinetic(EK)-Fenton process and Ozone chemical oxidation were investigated for tile removal of organic contaminants and heavy metals from the contaminated soil. In EK-Fenton process, accumulated electroosmotic flow(EOF) was 80 L for 26 days. Removal efficiency of TPH, As, and Ni were 61%, 36%, and 47%, respectively. The concentration of As was high near the anode due to the transport of anionic As toward the anode, while the concentration of Ni was high near the cathode by the movement of cationic Ni to the cathode. Field scale application of in-situ ozonation was carried out for removal of TPH in 3-D test cell (3 m$\times$2 m$\times$2 m). After 25 days of ozone injection, more than 80% of removal rate was observed through the test cell.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1038-1045
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• 2001

The electrokinetic technology was applied in bioremediation for the purpose of supplying a Pseudomonas strain capable of degrading diesel to contaminated soil bed, and their biodegradation of diesel was carried out after a desired cell distribution was obtained. Electrokinetic injection of the strain was made possible because the cells acted as negatively charged particles at neutral pH, and thus the cells were transported with a precise directionality through the soil mostly by the mechanism of electrophoresis and in part by electroosmosis. A severe pH change in the soil bed was formed due to the penetration of electrolysis products, which was harmful to the cell viability and cell transport. To achieve a desirable cell transport and distribution, the control of pH in soil bed by a recirculating buffer solution in electrode chambers was essential during the appliation of an electric field. The judicious selections of electrolyte concentration and conductivity were also important for achieving an efficient electrokinetic cell transport since a higher electrolyte concentration favored the maintenance of pH stability in soil bed, but lowered electrophoretic mobility on the other hand. With electrolyte solution of pH 7 phosphate buffer, a 0.05 M concentration showed a better cell transport buffer, a 0.05 M concentration showed a better cell transport than 0.02 M and 0.08 M. The cell under pH 8 were obtained, compared to the cells under pH 7 or pH 9 in a given time period Up to $60\%$ of diesel was degraded in 8 days by the Pseudomonas cell, which were distributed electrokinetically under the conditions of pH 8 ($1,800{\mu}S/cm$, a mixture of phosphate and ammonia buffers) and 40 mA in a soil bed of 15 cm length.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.3
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• pp.153-160
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• 2009

Vertical electrokintic-flushing remediation equipment was developed for the remediation of a radioactive soil near nuclear facilities. An optimum reagent was selected to decontaminate the radioactive soil near nuclear facilities with the developed vertical electrokintic-flushing remediation equipment, and the optimum remediation conditions were established to obtain a higher remediation efficiency. Namely, acetic acid was selected as an optimum reagent due to its higher remediation efficiency. When the electrokinetic remediation and the electrokinetic-flushing remediation results were compared, the removal efficiency of 4.6% and the soil waste solution volume of 1.5 times were increased in the electrokinetic remediation. When the potential gradient within an electrokinetic soil cell was increased by two times (4.0 V/cm), the removal efficiencies of $Co^{2+}$ and $Cs^+$ were increased by about 4.3%($Co^{2+}$ : 98.9%, $Cs^+$ : 96.7%). Also, when the reagent concentration was increased from 0.01M to 0.05M, the removal efficiency of $Co^{2+}$ was increased but that of $Cs^+$ was decreased. Therefore, the optimum remediation conditions were that the acetic concentration was $0.01M{\sim}0.05M$, the potential gredient was 4 V/cm, the injection of reagent 2.4ml/g, and the remediation period was 20days.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.910-915
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• 2005

In this study a series of tests(bench scale test) are carried out for increasing in strength of clayey soil by EK-Injection method. In addition, the effects of strength increase in the treated sample are measured by operating the vane shear test device during 25 days at 5 days intervals in order to estimate the effect of ground improvement caused by diffusion. The test results show that the strength increase was developed approximately double to 7 times in comparison to initial shear strength, and outstanding strength increase was created as much as 7 times while injecting the sodium silicate and phosphoric acid in anolyte and catholyte. In addition, the measured shear strength with the influence of diffusion and reduction of water-content had a tendency to converge in constant value in proportion to elapsed time. As a result of this study, strength increment developed by the influence of EK-Injection and diffusion rather than the reduction of water-content were high as 1000% on average