• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1398-1402
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• 2005

Riverbank filtration is a natural process using alluvial aquifers to remove contaminants and pathogens in river water for the production of drinking water. In riverbank filtration, the understanding of contaminant transport is an important task for the production of high quality drinking water. This study investigates the transport behavior of hydrophobic organic contaminants when colloids (dissolved organic matter and bacteria) are present in the aquifer. A mathematical model for the transport of contaminants is developed and solved numerically for various situations. Results show that in the riverbank filtration the presence of DOM and bacteria enhances the mobility of contaminant significantly. Sensitivity analysis indicates that the distribution of the total aqueous Phase contaminant is significantly affected by distribution coefficients which account for affinity of solid or colloidal Phase to contaminant.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.210-214
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• 2002

In this study, the coupled effect of electrokinetic and ultrasonic remediation technology was investigated for removing of heavy metal and organic matter at the same time. The laboratory tests were conducted using specially designed and fabricated electrokinetic and ultrasonic devices. The electrokinetic technique was applied to remove mainly the heavy metal and the ultrasonic technique was applied to remove mainly organic substance in contaminated soil. Diesel fuel and Cd were used as a surrogate contaminant for this test. A series of laboratory experiments involving electrokinetic and electrokinetic+ultrasonic flushing test were carried out. An increase in permeability and contaminant removal rate was observed in electrokinetic+ultrasonic flushing test.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.137-140
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• 2003

This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant degraded through cometabolism in dual-porosity soils during the in situ bioaugmentations. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept [Molz et at., 1986〕 were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailablity of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective in situ bioaugmentation scheme.

• Environmental Engineering Research
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• v.13 no.2
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• pp.73-78
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• 2008

For a given soil-contaminated site, a level of soil contamination is characterized and decisions on risk may be made from the risk assessment. The study evaluated critical design factors for the determination of sample size in the sampling design plan and the assessment of soil contaminant- leaching to groundwater. Two variables, the minimum relative detectable difference (T) and coefficient of variation (CV) were evaluated for the sample size determination. The minimum number of samples can be appropriately determined by CV under a T value greater than or equal to 0.2. Soil-contaminant leaching to groundwater was evaluated by using the Soil Screening Level equation of U.S. Environmental Protection Agency and the Risk Based Screening Level equation of American Society for Testing and Materials, with the same input parameters. The groundwater concentrations estimated from soil contaminant concentrations were significantly affected by the Darcy velocity of groundwater and the organic content of soil.

• Journal of Soil and Groundwater Environment
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• v.8 no.4
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• pp.12-20
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• 2003

This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant, TCE, degraded by cometabolism in dual-porosity soils during the installation of in situ biobarrier. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction in biobarrier due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailability of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective installation of biobarrier during in situ bioaugmentation scheme.

• Journal of Korea Water Resources Association
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• v.39 no.6 s.167
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• pp.511-520
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• 2006

Riverbank filtration is a natural process, using alluvial aquifers to remove contaminants and pathogens in river water for the production of drinking water. In Korea, most of the drinking water is supplied by surface water in-take. However, maintaining the quality of the drinking water becomes more and more difficult due to the increase of contamination. In riverbank filtration, the understanding of contaminant transport is an important task for the production of high quality drinking water and for the maintenance of facilities. In this paper, the transport behavior of hydrophobic organic contaminants is investigated when contaminants coexist with dissolved organic matter (DOM) and bacteria. In the developed model, the aquifer is thought of as a four phase system: two mobile colloidal phases, an aqueous phase, and a stationary solid matrix phase. The model equations are solved numerically for various situations. Results indicate that the presence of colloidal matters can enhance the mobility of contaminant significantly and that partitioning coefficients play an important role in the process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.129-132
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• 2000

In this research, we proposed the immobilization zone where the organic contaminant would be fixed, so that ground water could be prevented from the organic contaminants. The surfactant was adsorbed on the soil particles and the organic contaminants were partitioned into the hydrophobic tails of the surfactant in the immobilization zone. Surfactants with different molecular structures-SDDBS (sodium dodecylbenzenesulfonic acid), MADS (monoalkylated disulfonated diphenyl oxide), DADS (dialkylated disulfonated diphenyl oxide) - were used in this study. Up to the present, the research on the immolization simulated the saturated condition. But many site contaminated with organic contaminants and the zones where immobilization would be applied are unsaturated. In this research, in order to investigate the behaviors of surfactants and organic contaminants in unsaturated condition, the unsaturated columns were experimented, and their results were compared with the saturated case.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.246-249
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• 2002

Black shale that has relatively high organic carbon content was tested to determine its sorption phenomena and capacity for TCE. Conventional batch sorption tests were peformed at room temperature. The parameters that were thought to affect the TCE sorption were solution pH and dissolved organic matter. The effect of solution pH on TCE sorption was minimal, but the dissolved organic matter increased the amount of TCE sorbed on black shale. Thus, using black shale as sorbent for TCE in groundwater could save material costs by replacing high cost conventional activated organic carbon.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.388-394
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• 1998

In this study, the influence of soil contaminant on the cement solidification treatment was considered. Unconfined compression strength(UCS) test was carried out for solidificated specimen, Setting time was measured for cement slurry that was mixed with leachate and wastewater. It was appeared that treatment effect were affected by the the kind of soil, organic content, component of pore water and its concentration. And UCS of samples which were cured in the leachate were decrease about l/5. Especially for the marine clay, UCS of samples which were cured in leachate during 180 days were smaller than 90 days cured samples in the case of cement mixing ratio 5%, 10%.