• Journal of Soil and Groundwater Environment
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• v.19 no.5
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• pp.35-44
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• 2014

In this study, the bio-phytoremediation and phytoremediation technologies were applied to the soils contaminated with total petroleum hydrocarbons (TPH) and heavy metals to evaluate the remediation efficacy from May 2012 to December 2013. Poplar (Populus bonatii Levl.) and Sun Hemp (Crotalaria juncea L.) were selected and planted in phytoremediation practice. These plants were also utilized in the bio-phytoremediation practice, with the addition of earthworm (Eisenia fetida) and petroleum-degrading bacteria (Pseudomonos sp. NKNU01). Furthermore, physiological characteristics, such as photosynthesis rate and maximal photochemical yield, of all testing plants were also measured in order to assess their health conditions and tolerance levels in adverse environment. After 20 months of remedial practice, the results showed that bio-phytoremediation practice had a higher rate of TPH removal efficacy at 30-60 cm depth soil than that of phytoremediation. However, inconsistent results were discovered while analyzing the soil at 100 cm depth. The study also showed that the removal efficiency of heavy metals was lower than that of TPH after remediation treatment. The results from test field tissue sample analysis revealed that more Zinc than Chromium was absorbed and accumulated by the tested plants. Plant height measurements of Poplar and Sun Hemp showed that there were insignificant differences of growth between the plants in remediation plots and those in the control plot. Physiological data of Poplar also suggested it has higher tolerance level toward the contaminated soils. These results indicated that the two testing plants were healthy and suitable for this remediation study.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.94-103
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• 2014

In this study washing efficiency and desorption isotherms for heavy petroleum oil (HPO), Zn, and Pb bound to complex contaminated soils were examined using various soil flushing agents. Sodium dodecyl sulfate (SDS), methanol, ethylene diamine tetraacetic acid (EDTA), and citric acid were selected as soil flushing agents. 3% (w/v) and 4% SDS showed the highest removal efficiency for HPO, but the difference was not statistically significant (p > 0.05). Thus, 3% SDS was chosen as the best soil flushing agent for HPO. In the case of heavy metals, 0.1-M EDTA showed the highest removal efficiencies. But 0.05-M citric acid was selected due to its economic and eco-friendly strengths. The desorption isotherms obtained using Freundlich and Langmuir models indicated that the maximum desorption characteristics ($K_F$ and $Q_{max}$) of HPO with 4% SDS and 90% methanol and heavy metals with 0.1-M EDTA and 0.1-M citric acid, respectively, were markedly lower than in other cases. In addition, when 4% SDS and 90% methanol were used for HPO in the range of $C_e$ higher than 600 mg/L, and when 0.1M citric acid and 0.1M EDTA were used for Zn and Pb in the range of $C_e$ higher than 300 and 100 mg/L, respectively, the distribution constant converged to certain levels. Thus, constant values of $K_U$ and $K_L$ were determined. It was found that these constants represent the maximum desorption capacity and they can be used as distribution coefficients of desorption equilibrium for the flushing agents. The results of this study provided fundamental information for the selection of the best agents as well as for the process design and operation of soil washing/soil flushing of complex contaminated soils.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.161-167
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• 2011

We previously showed that five strains belonging to Pseudomonas could remove TPH (Total Petroleum Hydrocarbons) efficiently when they are applied to TPH-contaminated soil. We optimized the bioremediation condition using different hydrocarbons and nutrients conditions to improve the efficiency. We setup lab-scale column bioreactor to monitor TPH and diesel removal efficiency. When we applied five Pseudomonas sp. mixtures to 25,000 $mg{\cdot}kg^{-1}$ TPH-contaminated soil (diesel 10,000 $mg{\cdot}kg^{-1}$, kerosene 10,000 $mg{\cdot}kg^{-1}$, gasoline 5,000 $mg{\cdot}kg^{-1}$) with the optimum condition, 76.3% of TPH removal efficiency was shown for 25 days. Meanwhile, in the application of five Pseudomonas sp. mixtures to 20,000 $mg{\cdot}kg^{-1}$ diesel-contaminated soil with the optimum condition, 99.2% of diesel removal efficiency was shown for 40 days. In the application to lab-scale bioreactor with five high efficiency bacteria, 88.5% of TPH removal efficiency was shown for 45 days. Based on the results from this study, we confirmed that this mixed Pseudomonas sp. consortium might improve the bioremediation of TPH in contaminated soil, the efficacy can be controlled by improving the nutrients. We also confirmed that the nutrients and oxygen for biodegradation of TPH could contribute on the management and control of applications of these strains for the study of bioremediation of TPH-contaminated soil.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.61-68
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• 2006

Soil washing techniques coupled with high pressure air jet were applied for diesel-contaminated soils sampled by an underground oil reservoir of which the initial total petroleum hydrocarbon (TPH) ($2,828{\pm}206\;mg/kg$) exceeded 5 times of current standard level (500 mg/kg) regulated by the Soil-Environment Conservation Law. Through several tests, we found that the position of impeller has a critical impact for washing efficiencies. The highest washing efficiency was obtained at an oblique angle (30 degree) for the impeller and optimized mixing speed (300 rpm) that could have high shearing forces. Considered economical and feasible aspects, the optimum mixing time was 10 min. Rate constants of TPH removal derived from the first-order equation were not linearly increased as mixing speed increased, indicating that mechanical mixing has some limits to enhance the washing efficiencies. Application of high-pressure air jet in washing process increased the washing efficiency. This increase might be caused by the fact that the surface of micro-air bubbles strongly attached hydrophobic matters of soil particles. As the pressure of air jet increased, the separation efficiencies of TPH-contaminated soil particles increased. In the combined process of high-pressure air jet and mixing by impeller, the optimum mixing speed and air flow-rate were determined to be 60 rpm and $2\;kg/cm^2$, respectively. Consequently, the washing technique coupled with high-pressure air jet could be considered as a feasible application for remediating petroleum-contaminated soils.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.360-363
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• 2003

Bioremediation is often used for in situ remediation of petroleum-contaminated site. We studied the microbial degradation of hydrocarbon in an artificially diesel contaminated soil in laboratory microcosm. In control soil, about 30% of the initial TPH was diminished and the degradation of diesel oil was significantly enhanced by the addition of bioremediation agent (70% of TPH reduction).

• 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.

• Journal of Soil and Groundwater Environment
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• v.20 no.1
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• pp.1-6
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• 2015

The objectives of this study were to calculate the radius of influence (ROI) of well for an air-sparging (AS)/soil vapor extraction (SVE) system and to evaluate the applicability of the system applied for the remediation of the petroleum contaminated rail site. For air permeability test, three monitoring wells were installed at a location of 1.3 m, 2.3 m, 3.0 m from the extraction well. And the pressure of each monitoring well was measured by extracting air from the extraction well with the pressure and flow of $(-)2,600mmH_2O$ and $1.58m^3/min$. The ROI for an extraction well was calculated as 4.31 m. Air was injected into the injection well with the pressure and flow of $3,500mmH_2O$ and $0.6m^3/min$ to estimate the radius of influence for oxygen transfer. Oxygen concentrations of air from three monitoring wells were measured. The ROI of an injection well for oxygen transfer was calculated as 3.46 m. The 28 extraction wells and 19 injection wells were installed according to the ROI calculated. The AS/SVE system was operated eight hours a day for five months. The rail site was contaminated with the petroleum and concentrations of benzene, toluene, and xylene were over the 'Worrisome Standard' of the 'Soil Environment Conservation Act'. The contaminated area was estimated as $732m^2$ and contaminants were dispersed up to (-)3 m from the ground. During the operation period, soil samples were collected from 5 points and analyzed periodically. With the AS/SVE system operation, concentrations of benzene, toluene, and xylene were decreased from 7.5 mg/kg to 2.0 mg/kg, from 32.0 mg/kg to 23.0 mg/kg, from 35.5 mg/kg to 23.0 mg/kg, respectively. The combined AS/SVE system applied to the rail site contaminated with volatile organic compounds (VOCs) exhibited a high applicability. But the concentration of contaminants in soil were fluctuated due to the heterogeneous of soil condition. Also the effect of the remediation mechanisms was not clearly identified.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.45-53
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• 2000

Two extraction methods for total petroleum hydrocarbon (TPH) from contaminated soil were evaluated. The soil used for this study was sandy loam. Diesel oil was selected as representative petroleum hydrocarbons and was spiked at 100, 10,000, 50,000mg TPH/kg dry soil. Percentage recovery of TPH by shaking method was higher compared to Soxhlet extraction. At extraction time of 2 hours and sample to solvent ratio of 1 : 5, the highest percentage recovery was obtained. In this condition, percentage recovery of TPH in soil contaminated with 100mg/kg and 50,000mg/kg as TPH was 95.9% and 95.5%, respectively The volume of solvent lost by volatilization in shaking method was relatively small compared to Soxhlet extraction.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.776-780
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• 2013

TPH degrdation patterns in diesel contaminated soil was investigated with microwave radiation. When microwave radiation on the soil was applied, temperature increment of the aridic soil was quite low, but temperature in the moist soil was dramatically increased even if short period of running time. Up to 20% of the moisture content, the higher moisture content has more increment of temperature, whereas over 20% of the moisture content, temperature in the soil was rather decreased. when 100~700 W power of microwave radiation was applied into the contaminated soil, a lot of TPH removals was observed under 300 W, but negligible increment of TPH removal was detected over 300 W. 60% of TPH removal was achieved with initial 20% moisture content and microwave radiation. Additional 25% removal was accomplished when moisture content was kept constant during radiation period. It indicated that maintaining of constant moisture is an important factor for TPH removal with microwave radiation because moisture and temperature in the soil are decreased with reaction time.

• Environmental Analysis Health and Toxicology
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• v.17 no.4
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• pp.347-355
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• 2002

As concerns on the effects of soil contamination on human health have grown, more efforts have been made to quantify the effects. One of such efforts is the development of risk assessment methodology. The fundamental objectives of this approach is to investigate the alternative options that reduce the risk of hazardous chemicals results from environmental pollution, which will eventually lead to an accomplishment of removement of identified toxicants in polluted environment. The U.S. EPA Risk Assessment guidance for the superfund (RAGS) provides a methods for assessing the health risk of contaminated soils and determining the preliminary remediation goals (PRGs). Using this approach, we assessed the health risk and preliminary remediation goals of petroleum contaminated site in Kyounggi province.