• 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 Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.302-308
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• 2005

Nitrate is one of common contaminants frequently found in the bank filtrate. Biological autotrophic denitrification into permeable reactive barrier(PRB) system to reduce nitrate concentration in bank filtrate was implanted. The objectives of research are to investigate effect of inoculation, to evaluate alternative alkalinity sources, and to determine effect of hydraulic characteristics, such as retention time, flow rate on the performance of semi-pilot PRB system. Semi-pilot scale biological PRB system was installed using elemental sulfur and limestone/oyster shell as reactive materials near Nakdong River in Kyoungnam province, Korea. Nitrate concentration in bank filtrate was reduced by indigenous microorganisms in oyster shell as welt as by inoculating microorganisms isolated from the sludge of an anaerobic digester in a wastewater treatment plant. Oyster shell as well as limestone can be used as an alkalinity source. However, oyster shell resulted in suspended solids of effluent. As the flow rate in the system increased from 66 to 132 mL/min and accordingly the residence time decreased from 15 to 7.5 hours, nitrate concentration in effluent increased and nitrate removal efficiencies decreased from 75 to 58% at the fixed thickness of 80 cm of PRB.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.402-406
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• 2006

The physical and chemical characteristics of ALC were analyzed and showed 2.2 of specific gravity and 9.05 of pH. The results of leaching tests with standard method for soil and waste indicated heavy metals(Cu, Cd, Pb, $Cr^{6+}$) were under maximum concentration level. The anaerobic digestion sludge was attached in the surface of ALC within 90 hours. As the results of batch test, pH of the ALC and Bio-ALC were decreased from initial pH of ALC to 8.7 and 7.8 respectively Also, the concentration of heavy metals was rapidly eliminated in the solution with the batch test. The result of column experiment indicates that the removal efficiency of ALC was showed 66% of T-P, 60% of T-N, and 67% of CODcr. Also, removal efficiency of Bio-ALC was slightly higher than that of ALC in T-N (64%) and CODcr (74%).

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1060-1068
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• 2007

Perchlorate contamination in aquatic system is a growing concern due to the human health and ecological risks associated with perchlorate exposure. In spite of potential risks associated with perchlorate, drinking water standard has not been established worldwide. Recently, US EPA has issued new protective guidance for cleaning up perchlorate contamination with a preliminary clean-up goal of 24.5 ppb. In Korea, the drinking water standard and discharge standard for perchlorate has not been established yet and little information is available to address perchlorate problems. Perchlorate treatment technologies include ion exchange, microbial reactor, carbon adsorption, composting, in situ bioremediation, permeable reactive barrier, phytoremediation, and membrane technology. The process description, capability, and advantage/disadvantages of each technology were described in detail in this review. One of recent trends in perchlorate treatment is the combination of available treatment options such as combined microbial reduction and permeable reactive burier. In this review, we provided a brief perspective on perchlorate treatment technology and to identify an efficient and cost-effective approach to manage perchlorate problem.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.525-534
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• 2005

Adsorption experiments for As(V) and As(III) onto the surfaces of aerobic Pseudomonas aeruginosa, which can be readily isolated from natural media, were conducted under nutrient-absent conditions. While a small amount of As(III) was adsorbed on the bacterial cell surfaces, As(V) was not effectively removed from the solution through adsorption. The result was likely due to the electrostatic repulsion between anionic compounds of aqueous As(V) and cell surfaces of f aeruginosa. However, the bacteria forming biofilm reduced a large amount of aqueous As(V) to As(III), which indicated that microorganisms in most oligotrophic, natural geologic settings can mediate the behavior of aqueous As. Biobarriers designed to remove the various heavy metals in contaminant plume may practically lead to the enhancement of toxicity and mobility of As.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.23-26
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• 2004

Methyl Tertiary-Butyl Ether is one of several fuel oxygenates added to gasoline to improve fuel combustion and reduce tile resulting concentration of hydrocarbon. Thus, MTBE transfer readily to groundwater from gasoline leaking from Underground Storage Tank. Therefor, there are significant risks and costs associated with the water contamination. MTBE is far more water soluble than gasoline hydrocarbon. The purpose of the this study is to test the ability of ground tire with facultative bacteria. Bacillus brevis, to sorb MTBE. The process is consisted both batch and column experiment to determine the sorption capacity. And Biofilm is observed by SEM in the column. Finally, it is clear that ground tire represent an attractive and relatively inexpensive sorption medium for a MTBE. The authors can surmise that to determine the economic cost of ground tire utilization, tile cost to sorb a given mass of contaminant by ground tire will have to be compared to currently accepted sorption media. and Bacillus brevis strain was eliminated on MTBE, too. The biobarrier that ground tire with bacteria, has potential for use in the remediation of MTBE-contaminated environments.

• Resources Recycling
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• v.20 no.3
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• pp.28-39
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• 2011

This review investigated theoretical principals and practical application examples on recirculation system of soil washing-wastewater treatment-treated water recycling. As for technologies which have attempted to remediating metals-contaminated soil in and around country, there are reactive barriers, encapsulation, solidification/stabilization, soil washing, and phytoremediation. Among those, in particular, this review covers soil washing technology which physicochemically removes contaminants from soils. The major drawbacks of this technology are to generate a large amount of wastewater which contains contaminants complexed with ligands of washing solution and needs additional treatment process. To solve these problems, many chemical treatment methods have been developed as follows: precipitation/coprecipitation, membrane filtration, adsorption treatment, ion exchange, and electrokinetic treatment. In the last part of the review, recent research and field application cases on soil washing wastewater treatment and recycling were introduced. Based on these integrated technologies, it could be achieved to solve the problem of soil washing wastewater and to enhance cost effective process by reducing total water resources use in soil washing process.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.35-48
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• 2021

In this study, the assessment of field applicability of in-situ remediation of nitrate-contaminated groundwater located in Yesan-gun was performed. Zero-valent iron/bio composite media injected PRB (Permeable Reactive Barrier) and monitoring well were installed in the contaminated groundwater site and monitored main remediation indicators during the PRB operation. Nitrate, nitrite, ammonia, Fe ion, TOC, and turbidity were analyzed and the diversity and population of microorganism in the PRB installed site were investigated for the verification of effect of injected PRB. In the study site where is an agricultural area, a river flows from west to east that forms a river boundary and the southern area has an impermeable sector. It was found that nitrate flows into the river, which is similar as groundwater flow. Simulation result for the fate of nitrate in groundwater showed steady state of nitrate arrived after 3~5 years passed. However, it is just to consider current conditions with no additional input of contaminant source, if additional input of contaminant source occurs contamination dispersion and time for steady state are expected to be increased. The monitoring results showed that Fe ion, TOC and turbidity in groundwater were not clearly changed in concentration after PRB installation, which indicates adaptability of the injected PRB for remediation of groundwater with no additional harmful effect to water quality. The concentration of nitrate maintained less than 5mg/L until 42 days after PRB installation and recovered its initial concentration after 84 days passed and showed termination of reactivity of injected zero-valent iron/bio composite media for removal nitrate. Nitrite and ammonia ions found after installation of PRB indicates reductive removal of nitrate. And the outstanding increase of microorganism diversity and population of Betaproteobacteria Class which includes denitrification microorganism explains biologically reductive removal of nitrate in injected PRB.