• Journal of Soil and Groundwater Environment
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• v.15 no.1
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• pp.50-56
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• 2010

Oil contamination soil has been one of the most environmental social issues for decades in the inside and outside of country. The law of soil environmental preservation was carried out in the 1990s and the government controlled not only soil environment management and the remediation of contaminated soil but also promoted the development of remedial technology and cleanup business of contaminated soil by national policy. In addition to agriculture areas, the main oil contaminated sites are a gas station, oil reservoir, petro-chemical complex, site of railway carriage base and military camp. The contamination-frequency of agriculture area and effect sites are low but it has significantly important area on account of producing food for human beings. Therefore, we should be concerned about oil contamination damage of agriculture area. The oil contamination damage of agriculture area influenced drop of birth and breeding since the oil directly adheres to seeds and farm products even diffusion of contaminated soil to cultivation area. The studies of the crops and the food vegetation has not enough detailed data caused by the incident of oil contamination. This study investigated the effect of oil in germination and growth of selected plant seeds. In this study, we try to verify whether the oil contamination by accidents on farmland influenced the damage of farm produce and the mutual relation both oil contaminated soil or the vegetation of crops. The impact of oil on plant development was followed by phytotoxicity assessments. The plants exhibited visual symptoms of stress, growth reduction and perturbations in developmental parameters. The increase of the degree of pollution induced more marked effects in plants, likely because of the physical effects of oil. The relationships between the phytotoxicity contents of plants and growth reduction suggest a chemical toxicity of fuel oil. In addition, while cleaned up the contaminated soil under the standard of contaminated soil we examined it was suitable for region standard and it may have practical possibility for fill material of construction of afforestation and molding soil of landfill.

• Journal of Soil and Groundwater Environment
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• v.16 no.3
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• pp.10-16
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• 2011

The experimental studies for remediation of diesel contaminated soils were performed using subcritical water in laboratory scale. Contaminated soils from industrial area and artificially contaminated soils were utilized for soil remediation. Experimental system was composed for subcritical water to flow upward through the soil packed column for extracting contaminants. 10 g of contaminated soil was packed into the column and water flow rate was 2 mL/min. To evaluate the effects of temperature, pressure and treatment time on the removal efficiency, temperature was changed from 100$^{\circ}C$ to 350$^{\circ}C$, pressure from 50 bar to 220 bar and treatment time at the predetermined temperature from 0 min to 120 min. The purification efficiency increased as temperature increased. However, the effect of pressure and treatment time was low. Temperature 250$^{\circ}C$, pressure 50 bar and treatment time 30 min were selected for optimal operating condition for this study.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.373-381
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• 2005

The permeability of contaminated soil and elapsed time are important considering factors to in-situ soil remadiation. 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 which embedded with vertical drains. The contaminant concentration ratio (C/$C_0$) is analyzed with time and spatial changes in three different permeability areas which are $k=l.0{\times}10^{-5,}$ $l.0{\times}l0^{-6,}$ $l.0{\times}l0^{-7}\;_{m/s}$ by using the Gabr's equation. Results from numerical analysis indicate that the ratio (C/$C_0$) decreases as the elapsed time increases in every point, however, remediation efficiency decreases as the analyzing point is far from injection well to extraction one and is deeper from top level of contaminated area. And also it decreases as the permeability of contaminated area decreases. Especially, the lower permeability of contaminated area effects directly on the soil remediation, in this research, under condition which the permeability of contaminated area is $l.0{\times}l0^{-7}\;_{m/s}$, the maximum time needed to attain 90% clean up level ($t_{90}$) is 65,690 hours(7.5 years), it takes so much time to clean the low permeability contaminated soil.

• Journal of the Korean Professional Engineers Association
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• v.41 no.3
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• pp.24-29
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• 2008

Recently, the serious problems have been occurred due to the contaminated sites with heavy metals are increasing. There are several remediation technologies of the metal contaminated soil such as physical separation, washing with water or acid, biologically, electrically. Pytoremediation, ultrasonic etc. Among these technologies the physical separation can be put in a good option to solve the metal contaminated soil economically and environmental friendly. Because this technology has been already commercially certificated in the mineral processing field for a long time.

• Journal of Soil and Groundwater Environment
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• v.19 no.2
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• pp.16-24
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• 2014

To test the potential effects of extracellular electron shuttles (EES) on the rate and extent of heavy metal release from contaminated soils during microbial iron reduction, we created anaerobic batch systems with anthraquinone-2,6-disulfonate (AQDS) as a surrogate of EES, and with contaminated soils as mixed iron (hydr)oxides and microbial sources. Two types of soils were tested: Zn-contaminated soil A and As/Pb-contaminated soil B. In soil A, the rate of iron reduction was fastest in the presence of AQDS and > 3500 mg/L of total Fe(II) was produced within 2 d. This suggests that indigenous microorganisms can utilize AQDS as EES to stimulate iron reduction. In the incubations with soil B, the rate and extent of iron reduction did not increase in the presence of AQDS likely because of the low pH (< 5.5). In addition, less than 2000 mg/L of total Fe(II) was produced in soil B within 52 d suggesting that iron reduction by subsurface microorganisms in soil B was not as effective as that in soil A. Relatively high amount of As (~500 mg/L) was released to the aqueous phase during microbial iron reduction in soil B. The release of As might be due to the reduction of As-associated iron (hydr)oxides and/or direct enzymatic reduction of As(V) to As(III) by As-reducing microorganisms. However, given that Pb in liquid phase was < 0.3 mg/L for the entire experiment, the microbial reduction As(V) to As(III) by As-reducing microorganisms has most likely occurred in this system. This study suggests that heavy metal release from contaminated soils can be strongly controlled by subsurface microorganisms, soil pH, presence of EES, and/or nature of heavy metals.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.39-46
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• 1996

For the purpose of development of bioremediation technology for soil contaminated by chlorinated phenols, this study was focused on the isolation and characterization of bacteria capable of degrading chlorinated phenols, the establishment of analytical methods for chlorinated phenols, and the investigation of the contaminated sites. One site near the Incheon Industrial Complex was identified as a pentachlorophenol (PCP)-contaminated spot. The soil brought from the PCP-contaminated site contained 10-100$mu\textrm{g}$/g wet soil of PCP. Many bacterial strains capable of growing on a minimal medium containing PCP were isolated from 15 soil samples collected throughout the land, and among them, 10 active isolates were finally selected for the further studies on the biodegradability and for the use in in situ bioremediation of contaminated soil. These isolates showed species-specific pattern in PCP-decrease and cell growth in a minimal medium containing 500-1,000mg/ιPCP. Strain Bul degraded 90% of PCP at 216 hrs after incubation. Expecially, strain Bu34 was capable of degrading 4,000mg/ι PCP and was identified as Pseudomonas putida Bu34. It is seemed that the isolated active bacteria could be effectively used for the bioremediation of PCP-contaminated sites.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.150-157
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• 2007

The advanced bioremediation of diesel-contaminated soil through the exploration of bacterial interaction with plants was studied. A diesel-degrading rhizobacterium, Rhodococcus sp.412, and a plant species, Zea mays, having tolerant against diesel was selected. Zea mays was seeded in uncontaminated soil or diesel-contaminated soil with or without Rhodococcus sp. 412. After cultivating for 30 days, the growth of Zea mays in the contaminated soil inoculated with Rhodococcus sp. 412 was better than that in the contaminated soil without the bacterium. The residual diesel concentrations were lowered by seeding Zea mays or inoculating Rhodococctis sp. 412. These results Indicate that the simultaneous use of Zea mays and Rhodococcus sp. 412 can give beneficial effect to the remediation of oil-contaminated soil. Bacterial community was characterized using a 16S rDNA PCR and denaturing gradient gel electrophoresis (DGGE) fingerprinting method. The similarities of DGGE fingerprints were $20.8{\sim}39.9%$ between the uncontaminated soil and diesel contaminated soil. The similarities of DGGE fingerprints were $21.9%{\sim}53.6%$ between the uncontaminated soil samples, and $31.6%{\sim}50.0%$ between the diesel-contaminated soil samples. This results indicated that the structure of bacterial community was significantly influence by diesel contamination.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.108-113
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• 2022

Arsenic (As) uptake and accumulation from agricultural soil to rice vary depending on the soil environmental conditions such as soil pH, redox potential, clay content, and organic matter (OM) content. Therefore, these factors are important in predicting changes in the uptake and accumulation of As in rice plants. Here, we studied the chemical properties of As-contaminated and/or rice straw compost (RSC)-treated soils, the growth responses of RSC-applied rice plants under As-contaminated soils, the changes in As content of soil, and the relationship between As uptake and accumulation from the RSC-treated soils to the rice organs under As-contaminated soils. Rice plants were cultivated in 30 mg kg^-1 As-contaminated soils under three RSC treatments: 0 (control), 12, and 24 Mg ha^-1. No significant differences were indicated in the chemical properties of pre-experimental (before transplanting rice seedling) soils, with the exception of EC, OM, and available P₂O₅. As the treatment of RSC under 30 mg kg^-1 As-contaminated soils increased, EC, OM, and available P₂O₅ increased proportionally in soil. Increased soil RSC under As-contaminated soils increased shoot dry weight of rice plants at harvesting stage. As content in roots increased proportionally with RSC content, whereas As content in shoots decreased under As-contaminated soil at all stages of rice plants. Nevertheless, As accumulation were significantly decreased in both roots and shoots of RSC-treated rice plants than those in the plants treated without RSC. These results indicate that the use of RSC can mitigate As phytotoxicity and reduce As accumulation in rice plants under As-contaminated soils. Therefore, RSC can potentially be applied to As-contaminated soil for safe crop and forage rice production.

• Journal of Soil and Groundwater Environment
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• v.20 no.5
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• pp.26-33
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• 2015

Batch experiments were performed to investigate the feasibility of a surfactant-enhanced soil washing process for soils heavily contaminated with crude oil in Kuwait. TPH concentration of the contaminated soil was 223,754 mg/kg, sampled from the bottom of a vaporized oil extraction pond in the Burgan reservoir field. Commercialized eight nonionic surfactants (Tween and Tergitol series) were used to measure the aqueous solubility for the crude oil. Among them, two Tergitol surfactants were used to evaluate the TPH removal efficiency of the surfactant-enhanced soil washing for heavily contaminated Kuwait soil. The solubility of the crude oil in surfactant solution was in the order Tergitol 15-S-7 > Tergitol 15-S-9 > Tergitol 15-S-12 > Tween-80 > Tween-20 > Tween-60, which showed that the crude oil solubilities of the Tergitol series were higher than those of the Tween series. The TPH removal efficiencies of 2% and 5% Tergitol 15-S-9 solution were 59% and 65%, respectively. Because the residual TPH concentration in the washed soil was still higher than the clean-up level (10,000 mg/kg), the soil washing process was repeated five times. After the fifth washing, the residual TPH concentration in the soil went down to 7,680 mg/kg and its removal efficiency was 97%.

• Environmental Engineering Research
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• v.15 no.4
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.