• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.228-237
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• 2005

The main purpose of this study was to investigate the red water reducing effects of phosphate based inhibitor when it was applied to water distribution system. The effects of pH, alkalinity, calcium concentration in the reduction of the red water also studied. The most finished water in Korea showed relatively high corrosiveness and was required to introduce some types of corrosion reducing methods such as addition of alkalinity. The precipitation of $CaCO_3$ by addition of $Ca(OH)_2$ formed porous film on the surface of the carbon steel pipes and was displaced easily from the surface of the pipes; on the other hand, addition of zinc phosphate (ZOP) formed reliable film on the surface and reduced iron release and color. Although the main function of ZOP was to suppress the release of Pb and Cu, it also reduced iron concentration released from water distribution pipes.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.404-408
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• 2001

This paper focuses on the pilot-scale investigation of direct recycling of electric arc furnace (EAF) stainless steelmaking dust. The direct recycling of EAF dust is to make pellets with the mixture of the dust and the reducing agent carbon, then introduce the pellets to the EAF. The valuable metals in the dust are reduced and get into the steel as the alloying elements. Experiments simulating direct recycling in an EAF were performed using an induction furnace. But it seems difficult to reduce all metal oxides in the dust so that some metal reducing agents added in the late stage of reduction process. The valuable metals in the dust were reduced partly by carbon and partly by metal reducing agent for the economical concern. The recovery of iron, chromium and nickel from the flue dust and the amount of metal oxides in the slag were measured. The results showed that the direct recycling of EAF stainless steelmaking dust is practicable. It wes also found that direct recycling of flue EAF stainless steelmaking dusts does not affect the chemistry and quality of stainless steel produced in the EAF. It is benefit not only for the environmental protection but also for the recovery of valuable metal resources in this way.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.5
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• pp.355-363
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• 2010

High purity hydrogen, 97-99 vol.%, with CO at just ppm levels was obtained in a fixed bed of iron oxide employing the steam-iron cycle operation with reduction at 823K and oxidation in a steam-$N_2$ mixture at 773K TGA experiments indicated that temperature of the reduction step as well as its duration are important for preventing carbon build-up in iron and the intrusion of $CO_2$ into the hydrogen product. At a reduction temperature of 823K, oxide reduction by $H_2$ was considerably faster than reduction by CO. If the length of the reduction step exceeds optimal value, low levels of methane gas appeared in the off-gas. Furthermore, with longer durations of the reduction step and CO levels in the reducing gas greater than 10 vol.%, carbidization of the iron and/or carbon deposition in the bed exhibited the increasing pressure drop over the bed, eventually rendering the reactor inoperable. Reduction using a reducing gas containing 10 vol.% CO and a optimal reduction duration gave constant $H_2$ flow rates and off-gas composition over 10 redox reaction cycles.

• Journal of Ginseng Research
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• v.27 no.1
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• pp.1-10
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• 2003

In present study, we examined whether or not the pretreatment of Korean Red Ginseng (KRG) could protect hepatotoxicity induced by carbon tetrachloride (CCl$_4$) and D-galatosamine (GalN). For this study, we not only tested activity of various plasma enzymes (AST, ALT, SDH, LDH), which are used as indicators of liver disease, but also checked the change of liver components such as lipid, glutathione and cytochromes content, and several liver enzyme activity. Pretreatment of KRG for two weeks significantly reduced the elevated plasma enzyme activities induced by CCl$_4$ and GalN. Pretreatment of KRG also restored the hepatic enzymes, malonedialdehyde formation, and depletion of reduced glutathione content induced by CCl$_4$ and GalN to near normal level. However, ${\gamma}$-glutamylcysteine synthetase activity was lot affected by KRG. These results suggest that KRG shows the hepatoprotective effect by reducing lipid peroxidation, by reducing the activity of free radical generating enzymes, and by preserving the hepatic glutathione.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.221-227
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• 2019

During the operation, maintenance and decommissioning of nuclear power plant radioactive contaminated waste is produced. This waste is stored in an underground repository 60-100 meters below the surface. The metallic portion of this waste comprises mostly carbon and stainless steel. A long-term field exposure showed high corrosion rates, general corrosion up to 29 ㎛ a^-1 and localized corrosion even higher. High corrosion rate is possible if microbes produce corrosive products, or alter the local microenvironment to favor corrosion. The bacterial and archaeal composition of biofilm formed on the surface of carbon steel was studied using 16S rRNA gene targeting sequencing, followed by phylogenetic analyses of the microbial community. The functional potential of the microbial communities in biofilm was studied by functional gene targeting quantitative PCR. The corrosion rate was calculated from weight loss measurements and the deposits on the surfaces were analyzed with SEM/EDS and XRD. Our results demonstrate that microbial diversity on the surface of carbon steel and their functionality is vast. Our results suggest that in these nutrient poor conditions the role of methanogenic archaea in corrosive biofilm, in addition to sulphate reducing bacteria, could be greater than previously suspected.

• Journal of the Mineralogical Society of Korea
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• v.16 no.2
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• pp.171-180
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• 2003

The objective of this study is to investigate biogeochemical processes to sequester $CO_2$and metals utilizing metal-rich fly ash (MRFA). Microbial conversion of $CO_2$into sparingly soluble carbonate minerals has been studied using MRFA under different $pCO_2$and different bicarbonate concentrations. Scaling from test tube to fermentation vessels (up to 4-L) using metal-reducing bacteria and MRFA has proved successful at sequestering carbon dioxide and metals. $CO_2$sequestration via precipitation processes using MRFA may complement the process of $CO_2$capture from fossil fuel plants while potentially stabilizing fly ash wastes.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.745-755
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• 2010

GTX(Great Train Express), the wide area express train of a big city center of metropolitan area, is the best new transportation method able to realize 'Low Carbon Green Growth' for solving traffic congestion of the metropolitan area with the connection the metropolitan area into 40-minute life zone by speeding up the standardized velocity, making the route straight and reducing the compensation of land using the space of 40~50m below the ground. In the transportation sector all over the world, if it turned into the public transportation system focusing on the train at a point of time that low carbon green revolution takes the initiative, national competitiveness would be enhanced by reducing the emission of carbon from cars by 1/6. Accordingly, this study is to look into the efficient operation in accordance with GTX construction superintended by currently Gyeonggi province and to consider the optimum operation plan of GTX that are proper for the actual circumstances of the country by comparatively analyzing overseas cases that took their positions as new transportation by curtailment of transit time through highspeed such as London area, Paris area, and Tokyo area etc that are similar to Korean metropolitan area.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.47-54
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• 1999

SRB(Sulfate Reducing Bacteria) converts sulfate into sulfide using an organic carbon source as the electron donor. The sulfide formed precipitates the various metals present in the AMD (Acid Mine Drainage). This study is the fundamental research on heavy metal removal from AMD using SRB. Two completely mixed anaerobic reactors were operated for cultivation of SRB at the temperature of $30^{\circ}C$ and anaerobic batch reactors were used to evaluate the effects of carbon source, COD/sulfate($SO_4^=$) ratio and alkalinity on sulfate reduction rate and heavy metal removal efficiency. AMD used in this study was characterized by low pH 3.0 and 1000mg/l of sulfate and dissolved high concentration of heavy metals such as iron, cadmium, copper, zinc and lead. It was found that glucose was an organic carbon source better than acetate as the electron donor of SRB for sulfate reduction in AMD. Amount of sulfate reduction maximized at the COD(glucose)/sulfate ratio of 0.5 in the influent and then removal efficiencies of heavy metals were 97.5% of Cu, 100% of Pb, 100% of Cr, 49% of Mn, 98% of Zn, 100% Cd and 92.4% of Fe. Although sulfate reduction results in an increase in the alkalinity of the reactor, alkalinity of 1000mg/1 (as $CaCo_3$) should be should be added continuously to the anaerobic reactor in order to remove heavy metals from AMD.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.150.1-150.1
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• 2011

The global rise of greenhouse gas(GHG) emissions and its potentially devastating consequences require a comprehensive regulatory framework for reducing emissions, including those from the transport sector. alternative fuels and technologies have been promoted as a means for reducing the carbon intensity of the transport sector. Renewable fuel policies were historically motivated by energy security concerns, and to promoted agricultural industries. In the last decade, biofuels have also been discussed as low or net-zero carbon soures of energy for transportation. Hence, the development of biofuels has been supported by a range of policy instruments, including volumetric targets or blending mandates, tax incentives or penalties, preferential government purchasing, government funded research, development in world-wide. As one of the most powerfuel instruments, renewable fuel mandates require fuel producers to produce a pre-defined amount(or share) of biofuels and blend them with petroleum fuel. In this study, we reviewed Renewable Fuel Standard(RFS, USA), Renewable Transport Fules Obligation (RTFO, UK) as a renewable fuel mandate policy to reduce GHG. This includes not only mandate system for blending of biofuels in transport fuels, but also sustainability to use biofuels in this system.

• Journal of Construction Engineering and Project Management
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• v.1 no.1
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• pp.11-17
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• 2011

According to the United Nations Framework Convention on Climate Change (UNFCCC), many countries around the world have been concerned with reducing Greenhouse Gas (GHG) emissions. Reducing the level of building energy consumption is particularly important in bringing GHG down. Because of this, many countries including the US and the EU are enforcing energy-related policies. However, these policies are focused on management of single types of buildings such as public buildings and office buildings, instead of management on a national level. Thus, although various policies have been enforced in many countries, $CO_2$ management on a national level is still not an area of focus. Therefore, this study proposed a community-based $CO_2$ management process that allows government-led GHG management. The minimum unit of the community in this study is a plot, and the process consists of three steps. First, the current condition of the GHG emission was identified by plot. Second, based on the identified results, the GHG emission reduction target was distributed per plot by reflecting the weighted value according to (i) the target $CO_2$ reduction in the buildings in the standard year, (ii) region, and (iii) building usage and size. Finally, to achieve the allocated target reduction, building energy management was executed according to the properties of the building located on each plot. It can be expected that the proposed community-based $CO_2$ management process will enable government-level GHG management, through which environment-friendly building construction can be promoted.