• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.348-351
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• 2003

Trichloroethylene, which is one of the representative DNAPL, has been found in underground water sources as a result of the manufactural use, and disposal of the chemical. In this research, in situ air sparging method was chosen to reduce the TCE concentration from the source zone. The concentration reduction in the source zone resulting from air sparging is simulated using the modified STOMP Water-Air operational mode in a two dimensional axisymmetric domain and bench scale test is conducted to analyze the performance of air sparging. The results of laboratory tests are compared with numerical simulations.

• Ecology and Resilient Infrastructure
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• v.7 no.2
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• pp.134-144
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• 2020

In-situ stabilization is a remediation method using amendments to reduce contaminant availability in contaminated soil. We tested the effects of two amendments (furnace slag and red mud) on the availability of toxic trace elements (TTEs) and soil enzyme activities (dehydrogenase, phosphatase, and urease). The application of amendments significantly decreased the availability of TTEs in soil (p < 0.05). The decreased availability of TTE content in soils was accompanied by increased soil enzyme activities. We found significant negative relationships between the TTE content assessed using Ca(NO₃)_2^-, TCLP, and PBET extraction methods and soil enzyme activities (p < 0.01). Soil enzyme activities responded sensitively to changes in the soil environment (pH, EC, and availability of TTEs). It could be concluded that soil enzyme activities could be used as bioindicators or ecological indicators for soil quality and health in environmental soil monitoring owing to their high sensitivity to changes in soil.

• 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).

• Proceedings of the Korean Geotechical Society Conference
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• 1992.12a
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• pp.1-18
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• 1992

The contaminatlon of soil and groundwater by leachate from impmperly managed landfills, or by cheiicals and gasoline leaked flu underground storage tanks has buou a serious urldwide environmental problei. Most of those contaminants are adsorptive and absorptive into soul, while they are hardly soluble in water. Thus, the rate of self purification is very slow, causing persistent problems in water use and environmental protection when the contamination is left untreated. Biological remediatlon technologies utilize the ertraordlnary caperbllity of microorganisms In degrading a tilde spectrum of organic compounds. Among them, an in situ bioremediation technology Involves injection of supplementary materials into the subsurfce in order to bring about a significant Increase in the microbial activity. The Increased microbial activity helps remove the pollutants in situ, that is, without digging out contaminants, soil, or water. This paper focused on the features, possibilities, and limitations of the bioremedition technology.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.77-86
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• 2002

Surfactant enhanced in-situ soil flushing was performed to remediate the soil and groundwater at an oil contaminated site, where had been used as a military vehicle repair area for 40 years. A section from the contaminated site (4.5 m $\times$ 4.5 m $\times$ 6.0 m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average $K_d$ of 2.0$\times$$10^{-4}$cm/sec. Two percent of sorbitan monooleate (POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminated section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed on a gas-chromatography (GC) for TPH concentration in the effluent with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit (WWDL). The effluent TPH concentration from wells with only water flushing was below 10 ppm. However, the effluent concentration using surfactant solution flushing increased to 1751 ppm, which was more than 170 times compared with the concentration with only water flushing. Total 18.5 kg of oil (TPH) was removed from the soil and groundwater at the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. The removal efficiency of surfactant enhanced in-situ flushing was investigated at the real contaminated site in Korea. Results suggest that in-situ soil flushing could be a successful process to remediate contaminated sites distributed in Korea.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.17-28
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• 2010

As a preliminary survey to improve efficiency of well-based permeable reactive barrier system for groundwater remediation, this site-scale study was carried to identify the flowpaths and controlling factors of plume at a remediation site in Suwon City, Korea. A total of 22 monitoring wells were installed as a grid system in the $4m{\times}4m$ square area by 1-m interval. For the groundwater characterization, various tests were performed including water-level monitoring, water sampling & analysis, pumping and slug tests, and tracer tests. The aquifer appeared to be unconfined with hydraulic conductivities (K) ranging from $2.6{\times}10^{-4}cm/s$ to $9.5{\times}10^{-3}cm/s$. The average linear velocity of groundwater was estimated to be $2.94{\times}10^{-6}m/s$, and the longitudinal dispersivity of a conservative tracer to be $5.94{\times}10^{-7}m^2/s$. Groundwater plume moves preferentially through the high-K zones, and the relatively high ion concentrations along the low-K zones implying deterred groundwater flow. Consequently, the spatial variation of hydraulic conductivity caused by aquifer heterogeneity and anisotropy appears to be the most important factor to maximize the effect of plume treatment system for application of in-situ groundwater remediation techniques.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.22-25
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• 2002

The effect of in-situ chemical oxidation on the indigenous soil microorganisms (total microbes and PAH-degrading microbes) and contaminant removal were investigated. Field soil contaminated with diesel in gas station was collected and the soil was treated from 0 to 900 minutes by in-situ ozonation as chemical remediation. The treated soil samples were incubated with supplying oxygen during the 9 weeks to understand the characteristics of microbes regrowth, damaged by ozone. The sharp decrease of aromatic fraction and TPH was observed within 60 minutes of ozone application and aromatic fraction and TPH then slowly decreased. The phenanthren-degrading bacteria were the most sensitive to ozonation, because 1 hour of ozonation reduced the microbes from 10$^{6}$ CFU/g-soil to below detection limits.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.172-175
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• 2003

Field scale application of in-situ ozonation were carried out for remediation of variably saturated soils contaminated with diesel fuel with 3 dimensional test cell (3m$\times$2m$\times$2m). After 20 days of ozone injection, more than 90% of removal rate was observed through the 3-D test cell. This result might be caused by uniform distribution, relatively low oxidant demand, and low water content of soils, as well as high oxidation potential of ozone. However, less than 50 % of injected ozone was monitored through the 3-D test cell even after 20 days of injection.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.199-202
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• 2002

Many methods have been developed for the remediation of contaminated soil and groundwater. Among those technologies, in-situ bioremediation is most likely to be cost-effective method for petroleum hydrocarbon contamination. But the in-situ bioremediation can require more time to remediate hydrocarbon-contaminated soil and groundwater than other methods. Therefore we intended to save time of in-situ bioremediation using a biological additive to activate indigenous microbes in soil. The additive, 'Inipol EAP 22' stimulates the growth of specific flora, significantly accelerating the speed at which hydrocarbons are biodegraded. And it hans been tested in accordance with protocol approved by the USEPA and is registered on the National Contingency Plan Product Schedule List. In the experiment, three soil samples contaminated with fuel oil were prepared in the same concentration. Inipol EAP 22 was not added to one sample and was added to the other two samples with 5% and 10% of hydrocarbon by weight respectively. And $CO_2$gas derived from bacterial respiration was analyzed in each samples for 15 days. As a result, 145% and 153% of $CO_2$ evolution (microbial respiration) against the sample without 'Inipol EAP 22' occurred in samples with 'Inipol EAP 22' addition of 5% and 10%, respectively

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.49-51
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• 2005