• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.34-56
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• 2001

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.665-675
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• 2007

In-situ Air Sparging (IAS, AS) is a remediation technique in which organic contaminants are volatilized from saturated zone to unsaturated layer. This study focuses on the removal and interaction of Volatile Organic Compounds (VOCs) and $CO_2$, and Total Petroleum Hydrocarbon (TPH) in saturated and unsaturated, and air space zone on the unsaturated soil surface. Soil sparging temperature of hot air has risen to $34.9{\pm}2.7^{\circ}C$ from $23.0{\pm}1.9^{\circ}C$ for 36 days. At the diffusing point, fluid TPH concentrations were reduced to 78.7% of the initial concentration in saturated zone when hot air was sparged. The TPH concentrations were decreased to 66.1% for room temperature air sparging. The amount of VOCs for hot air sparging system, in air space, was approximately 26% larger than constant air sparging system. The amount of $CO_2$ was 4,555 mg (in unsaturated zone) and 4,419 mg (in air space) when hot air was sparged was 3,015 mg (in unsaturated zone) and 3,634 mg (in air space) for room air temperature in the $CO_2$ amount. The removals of VOCs and biodegradable $CO_2$ through the hot air sparging system (modified SVE) were more effective than the room temperature air sparging. The regression equation were $Y=976.4e^{-0.015{\cdot}X}$, $R^2=0.98$ (hot air sparging) and $Y=1055e^{-0.028{\cdot}X}$, $R^2=0.90$ (room temperaure air sparging). Estimated remediation time was approximately 500 days, if final saturated soil TPH concentration was set to 1.2 mg/L application of tail effect.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.624-629
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• 2005

The purpose of this study is to investigate the performance of nitrogen removal using autotrophic microorganism in the Membrane-Attached Biofilm Reactor (MABR). The treatment system consists of an aerobic MABR (R1) for nitrification and an anaerobic MABR (R2) for hydrogenotrophic denitrification. Oxygen and hydrogen were supplied through the lumen of hollow-fiber membranes as electron acceptor and donor, respectively. In phase Ι, simultaneous organic carbon removal and nitrification were carried out successfully in R1. In phase II, to develop the biofilm on the hollow-fiber membrane surface and to acclimate the microbial community to autotrophic condition, R1 and R2 were operated independently. The MABRs, R1 and R2 were connected in series continuously in phase III and operated at HRT of 8 hr or 4 hr with $NH_4{^+}-N$ concentration of influent, from 150 to 200 mgN/L. The total nitrogen removal efficiency reached the maximum value of 99% at the volumetric nitrogen loading rate of $1.20kgN/m^3{\cdot}d$ in the combined MABR system with R1 and R2. The results in this study demonstrated that the combined MABR system could operate effectively for the removal of nitrogen in wastewater not containing organic materials and can be used stably as a high rate nitrogen removal technology.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.256-262
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• 2005

The purpose of this study is to investigate the performances of organic removal and methane recovery by using a full scale two-phase anaerobic system. The full scale two-phase anaerobic process was consists of an acidogenic anaerobic baffled reactor (ABR) and a methanognic upflow anaerobic sludge blanket (UASB) reactor. The volumes of acidogenic and methanogenic reactors were designed to $28.3m^3$ and $75.3m^3$. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 mg/L after screening (average concentration is 10,280 mg/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed $2,740{\pm}330 mg/L$ by representing average COD removal efficiency was $71.4{\pm}8.1%$ when the operating temperature was in the range of $19-32^{\circ}C$. The effluent SCOD concentration was in the range of 2,000-3,000 mg/L at the steady state while the volatile fatty acid concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70% of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.215-222
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• 2004

The sewages produced from small villages, rural community, drinking water reservation area and park which doesn't have sewage piping system can be caused a serious water pollution at the restricted areas. The objective of this research was to suggest an economical and effective sewage treatment method by investigating the removal of the organics, nitrogen, and phosphorus in the multi-soil-layering reactor. Soil, natural zeolite, and iron slag were used as a supporting media of multi-soil-layering in this research. The purpose of natural zeolite addition was to maintain the consistent ammonium exchange capacity by providing a sequential environment, and that of iron slag addition was to remove phosphorus by adsorption. Continuous experiment of lab-scale single-soil-layering (S-1), multi-soil-layering (S-2), and mixed-soil-layering (S-3) methods were studied to compare and optimize three different types of the reactors. The organic removal efficiencies showed more than 90% in all three reactors. While S-1 and S-3 reactors showed about T-N removal of 31%, 45%, respectively, the average T-N removal efficiency of the S-2 reactor represented an 87%. In conclusion, that results suggest that the multi-soil-layering reactor could be effectively utilized as a plant for treatment of small village sewage.

• Archives of design research
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• v.17 no.2
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• pp.113-122
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• 2004

Modern society came to enjoy dramatically advanced information technologies by the digitalization of New Media with the improvement of communication technologies and interaction between various information system and technologies. New service by web, not only text but image, audio and moving image have opened new experience possible for us. The development was possible because the web has characteristics of media making Remediation of various media possible. The web has remediated newspaper, magazines, TV, audio, movie by taking them, competing with them, attacking them and absorbing them. As a result, now we can enjoy various characteristics of different media at the Web. This study is to look into the effectiveness of Remediation at web design through various case studies. This study also is to seek more effective methods of expressions in the web and future improvement direction.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.637-642
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• 2005

The focus of this study was to examine the phosphorus removal characteristic by zirconium mesoporous structured material synthesized on various conditions. The zirconium sulfate-surfactant mesoporous structured material(ZS) was synthesized by hydro-thermal synthesis. The material has regular hexagonal array of surfactant micelles and sulfate ion ($HSO_4{^-}$). We confirmed that sulfate ion in zirconium mesoporous structured material can be ion-exchanged with phosphate ion ($H_2PO_4{^-}$) in phosphoric acid solution. On the X-ray diffraction (XRD) pattern of ZS, three peaks which shows the important characteristics of hexagonal crystal lattice were observed at (100), (110) and (200). The transmission electron micrograph (TEM) show high crystallization with pore size about $47{\AA}$. The maximum adsorption capacity of ZS was as great as 3.2 mmol-P/g-ZS. From the adsorption isotherm, correlation coefficients were higher for the Langmuir isotherm than the Freundlich isotherm. With the respect of chain length of surfactant, the adsorption capacity for phosphate synthesized with C12 was higher than C16 and C18. The highest amount of adsorbed phosphate on ZS was observed at the surfactant-to-zirconium molar ratio of 0.5 to 1.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.139-165
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• 2019

The current status and prospect of decommissioning technology development at KAERI are reviewed here. Specifically, this review focuses on four key technologies: decontamination, remote dismantling, decommissioning waste treatments, and site remediation. The decontamination technologies described are component decontamination and system decontamination. A cutting method and a remote handling method together with a decommissioning simulation are described as remote dismantling technologies. Although there are various types of radioactive waste generated by decommissioning activities, this review focuses on the major types of waste, such as metal waste, concrete waste, and soil waste together with certain special types, such as high-level and high-salt liquid waste, organic mixed waste, and uranium complex waste, which are known to be difficult to treat. Finally, in a site remediation technology review, a measurement and safety evaluation related to site reuse and a site remediation technique are described.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.283-286
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• 2002

Solubilization and partitioning of naphthalene was investigated in an aqueous system containing soils and surfactants. The environmental behavior of polycyclic aromatic hydrocarbons(PAHs) was mainly governed by their solubility and partitioning properties on soil media in a subsurface system. In surfactant-enhanced remediation systems, surfactants might be an additional variable. a natural soil ,silica and kaolinite were tested as soil media. two nonionic surfactants, Triton X-100 and Hydropropy1-$\beta$-cyclodextrin (HPCD) were employed for naphthalene solubilization. Naphthalene showed linear on natural soil while non-linear sorption on silica and kaolinite. Soils have higher sorption capacity for Triton X-100 than HPCD indicating Triton X-100 formed ad-micelle on the soil surface. Desorption study showed a hysterysis and reversible desorption. The partitioning coefficient(K$_{D}$) of naphthalene was increased as the concentration of surfactant was increased. (below CMC), however, the coefficient was decreased above CMC. This indicates that naphthalene is partitioned into the micelles and the partition occurs competitively on both ad-micelle and free micelles as surfactant concentration increases. Therefore, the target compounds to be dissolved into aqueous phase in a surfactant enhanced remediation system might be highly partitioned on to the ad-micelle resulting in an adverse effect rather increased solubilization would be achieved.d.