• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.576-581
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• 2002

In order to simultaneously vitrify the ton Exchange Resin(IER) and Dry Active Waste(DAW) generated from the Nuclear Power Plants, a vitrification pilot test was conducted using an induction cold crucible melter. The PCT result evaluating the chemical durability of the vitrified from showed that the final glass was more durable than the benchmark glass. Liquidus temperature for the final vitrified form was 1048 K(775$\^{C}$) fur heat treatment experiments. The value of the compressive strength for the vitrified form was ninety times higher than the regulation limit, 34 kg/㎠. The glasses on bottom, middle and top of the CCM were homogeneous with no secondary phase. The precipitation of the magnetic metal phase was able to be avoided by simultaneously fEeding of DAW with IER containing strongly reducing organics. Volume reduction factor of 74 was achieved through the vitrification Pilot test for mixed waste.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.333-339
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• 2008

We investigated death rates, growth rates and recruitment of culms in two neighboring bamboo (Phyllostachys bamboosoides) stands nested in by two different bird species to analyze stand structure and to design conservation strategies. A third bamboo grove not used by birds, the Taewha stand, was included as a control stand. The bamboo stand occupied by birds in the family Ardeidae (the Ardeidae stand) had an approximately 1.5 times higher culm density than the stand occupied by birds in the family Corvidae (the Corvidae stand). The crude death rate and the number of newly emerged shoots were also higher in the Ardeidae stand than the Corvidae stand. The death rate for bamboo in the Ardeidae stand was not dependent on diameter at breast height (DBH) and was almost 40% for culms of all sizes, whereas most dead culms in the Corvidae stand were < 4 cm DBH. Consequently, we conclude that in the Ardeidae stand, density-independent causes of death are operating, while density-dependent factor are more important in the Corvidae site. The results of soil analysis in these stands suggest that the density-independent death pattern observed in the Ardeidae stand may be due to soil acidification resulting from wastes produced by the birds during breeding. On the other hand, the culm distribution and death patterns in the Corvidae stand suggest that the stand characteristics were not affected by the nesting birds. These results suggest that different conservation strategies must be applied to conserve bamboo groves used by ardeids and corvids for nesting.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.184-193
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• 1998

In order to dispose radioactive wastes safely, it is needed to understand the mechanical, thermal, fluid behavior of rockmass and physico-chemical interactions between rockmass and water. Also, the knowledge about mechanical and hydraulic properties of rocks is required to predict and to model many conditions of geological structure, underground in-situ stress, folding, hot water interaction, intrusion of magma, plate tectonics etc. This study is based on researches about rock mechanics issues associated with a waste disposal in deep rockmass. This paper includes the mechanical and hydraulic behavior of rocks in varying temperature conditions, thermo-hydro-mechanical coupling analysis in rock mass and deformation behavior of discontinuous rocks. The mechanical properties were measured with Interaken rock mechanics testing systems and hydraulic properties were measured with transient pulse permeability measuring systems. In all results, rock properties were sensitive to temperature variation.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.119-126
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• 1997

Recently, duc to highly increased consumption of' ngg~.egatc>s f o ~ . construction. studies have focused on the effective utilization of rock wastes abandoned so far. This study was designed, firstly, to determine t,hc petrological, g'ochemical and mechanical cha~,acte~istics of' crushed limestone aggregates in thc Samhwa district for suitable construction aggregates and, secondly, to offer basic data for cff'ective utilization of low grade limestones. Results of' the petrographic st,udy indicates that the crushed limestone aggregates in the Samhwa district can bo separate4 into two groups, namely f'inc-grained and cowlxcgrained limestones. Dominantly distributed fine-grained limestone containing some dolomite has higher Mgo and $SiO_2$ contents compared to the coarse-graincd limestonr. It, can be classified as medium strength rock by the physical and mcxhanical pi.opertics. I3ased on the size of' mineral grains and chemical compositions, it is suggested that the crushed limestone aggregates in t,his study area would bctkr be u s ~ i for asphalt concr.ctt., road pavement, or railroad ballast materials than for cement concrete.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.79-84
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• 2003

The main objective of this study was to investigate the chemical characteristics of post-harvest biomass burning aerosols from field burning of barley straw in late spring and rice straw in late fall in rural area in Korea. 12-hr integrated intensive sampling of $PM_{10}$ and $PM_{2.5}$ biomass burning aerosols had been conducted continuously at Gwangju, Korea 4-15 June 2001 and 8 October-14 November 2002. The fine and coarse particles of biomass burning aerosols were collected for mass, ionic, elemental, and carbonaceous species analysis. Average fine and coarse mass concentrations of biomass burning aerosols were measured to be 129.6, 24.2 ${{\mu}gm}^{-3}$ in June 2001 and 47.1, 33.2 ${{\mu}gm}^{-3}$ in October to November 2002, respectively. Exceptionally high level of $PM_{2.5}$ concentration up to 157.8 ${{\mu}gm}^{-3}$ well above 24-hour standard was observed during the biomass burning event days under stagnant atmosphere condition. During biomass burning periods dominant ionic species were $Cl^{-}$, ${NO_3}^{-}$, ${SO_4}^{2-}$, and ${NH_4}^{+}$ in fine and coarse mode. In the fine mode $Cl^{-}$ and ${KCl}^{+}$ were unusually rich due to the high content of the semiarid vegetation. High OC values and OC/EC ratios were also measured during the biomass burning periods. Increased amount of fine aerosols with high enrichment, which were originated from biomass burning of post-harvest agricultural waste, resulted in extremely severe particulate air pollution and visibility degradation in the region. Particulate matters from open field burning of agricultural wastes cause great adverse impact on local air quality and regional climate.

• Journal of The Korea Institute of Healthcare Architecture
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• v.23 no.2
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• pp.63-72
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• 2017

Purpose: The purpose of this study is to review the material handling system of the Airborne Infection Isolation Hospitals which is the one of the key elements of infection control and to improve the basic data for the planning and design of those facilities. Methods: Research was conducted by literature reviews and case studies for the material handling system of domestic and foreign Isolation hospitals. Results: The result of this study can be summarized into three points. First, a general isolation unit and a high level isolated unit need to be distinguished in terms of efficiency and safety. In particular, it is desirable that a high level isolated unit have to completely separate clean and soiled circulations, and soiled corridor should be installed by those means. By doing this, the medical staff can observe patient rooms and supply clean materials directly in the clean zone without wearing PPE, so that safety and work efficiency can be improved at the same time. Second, for the safe disposal of wastes, it is desirable to install a dedicated sterilizer per ward and sterilize it at least in the ward. In addition, It is desirable to install a central waste treatment room and a dedicated soiled corridor in consideration of the inadequate handling capacity and emergency situation. Third, the characteristics of material flow chart in the negative pressured isolation hospitals and the corresponding material handling system have been presented. Implications: Infection control is very important in safety, but it is necessary to respond to the symptoms of the patient.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.64-68
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• 2010

Recently, MBT(Mechanical Biological Treatment) facilities were built up and operated to separate and recycle MSW(Municipal Solid Wastes)in South Korea. However, the size distribution of MSW is very rough, and it is causing operation problem because MSW would be crushed in undersize diameter by mechanical equipment before feeding each seperation process. Also, the organic material should be pre-seperated to reuse recycle material in MSW. In this research, the reactor of 1ton/batch using the super-heated steam was tested to present the separation efficiency and the size distribution of MSW by experimental factors.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.533-536
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• 2009

The gasification technology is a very flexible and versatile technology to produce a wide variety products such as electricity, steam, hydrogen, Fisher-Tropsch(FT) diesels, Dimethyl Ether(DME), methanol and SNG(Synthetic Natural Gas) with near-zero pollutant emissions. Gasification converts coal and other low-grade feedstocks such as biomass, wastes, residual oil, petroleum coke, etc. to a very clean and usable syngas. Syngas is produced from gasifier including CO, $H_2$, $CO_2$, $N_2$, particulates and smaller quantities of $CH_4$, $NH_3$, $H_2S$, COS and etc. After removing pollutants, syngas can be variously used in energy and environment fields. The pilot-scale coal gasification system has been operated since 1994 at Ajou University in Suwon, Korea. The pilot-scale gasification facility consists of the coal gasifier, the hot gas filtering system, and the acid gas removal (AGR) system. The acid gas such as $H_2S$ and COS is removed in the AGR system before generating electricity by gas engine and producing chemicals like Di-methyl Ether(DME) in the catalytic reactor. The designed operation temperature and pressure of the $H_2S$ removal system are below $50^{\circ}C$ and 8 kg/$cm^2$. The iron chelate solution is used as an absorbent. $H_2S$ is removed below 0.1 ppm in the H2S removal system.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.415-421
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• 2004

Litter wastes on highway runoff are gradually being considered one of the major pollutants of concern in protecting the integrity of receiving waters for beneficial use. The California State Water Resources Control Board has identified in their 303(d) list at least 36 water bodies where trash or litter is considered a pollutant of concern. The first TMDL adopted by the Region 4 (Los Angeles area) of the California State Water Quality Control Board was for trash in the Los Angeles River. The first flush characteristic study was developed to obtain first flush water quality and litter data from representative stormwater runoff from standard highway drainage outfalls in the Los Angeles area. Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over two years. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. The event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. Event mean concentrations were ranged 0.0021 to 0.259g/L for wet gross pollutants and 0.0001 to 0.027g/L for wet litters. The first flush phenomenon was evaluated and the impacts of various parameters such as rainfall intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Litter volume and loading rates appear to be directly related to peak storm intensity, antecedent dry days and total flow volume.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.2
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• pp.135-143
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• 2018

Objectives: There have been many studies on exposure assessment of workers at companies using asbestos as a raw material and at sites of the removal of materials containing asbestos. However, no research has been carried out on the asbestos exposure of workers in industries involving asbestos-containing waste, such as workers at collection and transportation service companies, mid-treatment companies(solidification of asbestos-containing waste), and landfill sites. The objective of this study was to assess the asbestos exposure concentrations of workers in industries handling waste containing asbestos. Methods: For this study, we carried out field investigations at 15 companies: seven collection and transportation service companies, three mid-treatment companies, and five final treatment companies(landfill sites). We took both personal and area samples. Results: The range of asbestos exposure levels of workers handing asbestos-containing wastes at collection, mid-treatment, and landfill companies were 0.000 fibers/cc-0.009 fibers/cc, 0.000 fibers/cc-0.038 fibers/cc, and 0.000 fibers/cc-0.024 fibers/cc, respectively. Conclusions: The asbestos exposure levels of workers at mid-treatment companies were higher than those at collection and transportation companies and at final treatment companies. In the case of collection and transportation workers, the possibility of exposure to levels exceeding those found in the present study is not particularly high considering the characteristics of the work. However, in the case of intermediate or final disposal workers, it is considered that there is a possibility of exposure to levels above those found in this study.