• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.75-81
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• 1998

In most of studies on solidification/stabilization with waste, small columns have been used to examinate adsorption or leachate. However, these experiments using small apparatus have been limited to apply with the field. In this study, considering an application to the field, a large Lysimeter(100cm$\times$100cm$\times$100cm) used for the simulation. Then, the open dumping waste was mixed directly with bentonite to simulate the stabilization of waste, environmental aspects and several basic tests. As a result, the concentration of heavy metals and contaminated substances changed with bentonite rate. Most of contaminated substances were decreased in leaching with increased mixing rate of bentonite. Especially, the concentration of CODcr removed 25~30%. Also, the residual soil in dumping waste produced approximately 80% of total volume by 40$\times$40mm screen.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.386-389
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• 2002

It may be necessary to apply a daily fever to operate the municipal solid waste landfill. The daily cover helps to control nuisance factors such as the escape of odors, dusts and airborne emissions, and can control the population of disease vectors. Also it may be reduce the infiltration of rain, decreasing the generation of leachate and the potential for surface water and groundwater contamination. Because of its usual availability and traditional usage as the municipal solid waste landfill, soil remains as the most common daily cover material. However, soil tends to reduce the volume of dumping waste c;3pacity in the landfill, it also reduces a period of using in the landfill. Therefore, it is necessary to research about Alternative Daily Cover Materials (ADCMs) because of the limitation of landfill sites. Recently, The types of ADCMs are classified into geosynthetics, forms, spray-ons, indigenous materials. In this study, the authors have tested the spray type of Alternative Daily Cover(ADC) using by flyash, alum with cement. The development. of ADCMs will be highly effective in terms of prolongation using landfill.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.266-269
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• 2003

To understand the long-term leach behavior of a borosilicate waste glass in a repository, the leaching experiment with three kinds of simulated borosilicate waste glasses has been carried out since the middle of 1997. The five years results indicate that a boron would be applied as an indicator of a long-term leaching of their borosilicate waste glasses and that their long-term leach rates have a tendency to be close to about $0.03g/m^2-day$ even though their compositions and their ratios of the surface area to the volume of leachate are different.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.186-193
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• 2009

Since its opening in 1992, Sudokwon Landfill has become a landfill in which wastes generated from more than 22 million people are treated and disposed of. Its first phase landfill was closed in 2000 and the second phase landfill is in operation since then. The Korean environmental policies on refuse have drastically evolved for the last decade or so. From merely safe containment of wastes, the utilization of them as a source for energy generation and the minimization of waste volume to be filled in landfills are in the mainstream. Keeping in pace with the new trends, several challenging projects are in their way to blossom in Sudokwon Landfill. This paper briefs some important activities in the landfill. They are (1) geotechnical issues related to the construction and maintenance of the $1^{st}$ and $2^{nd}$ Landfills and (2) landfill gas and bioreactor which are recently emerging in the market.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.91-102
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• 2009

In this study, to estimate the transforming (runoff and leachate) rate of the organic fertilizer made of livestock resources to farm land, laboratory scale test was conducted and the results were obtained as follows: The runoff volume from farm land showed the tendency of increase according to the increase of rainfall intensity. The most rainfall leachated into the underground at the rainfall intensity of 20mm/hr, and rainfall of 5L or less leachated at the rainfall intensity of > 32.4 mm/hr. This shows that surface runoff largely depends on the rainfall intensity when soil characteristic and hardness are similar in each site. When liquid compost was fertilized, the surface runoff was similar with the results from the reactor fertilized by compost, and leachate flow was found to be lower than compost. The runoff ratio of contaminant parameters from farm land were BOD 0.00003,, $COD_{cr}$ 0.00006, TN 0.00056, TP 0.00011, TOC 0.00005, Especially, the runoff ratio of TN showed 10 folds higher than other parameters. On the other hand, the runoff ratio of SS showed higher value of 0.001, and colloid particles of soil caused this result rather than the leachate from compost fertilizer. At all ranges of rainfall intensity, fertilizer removal ratio by farm land was found to be 94.9~98.4% for compost and 85.8~98.1% for liquid compost in terms of BOD. For TN, it resulted in 96.6~98.4% for compost and 97.2~98.5% for liquid compost, and thus the most fertilizer from livestock resources were shown to be reduced through farm land application.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.260-266
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• 2008

Small lysimeter experiment under rain shelter plastic film house was conducted to investigate the effect of soil characteristics on the leaching and soil solution concentration of nitrate and phosphate. Three soils were obtained from different agricultural sites of Korea: Soil A (mesic family of Typic Dystrudepts), Soil B (mixed, mesic family of Typic Udifluvents), and Soil C (artificially disturbed soils under greenhouse). Organic-C contents were in the order of Soil C ($32.4g\;kg^{-1}$) > Soil B ($15.0g\;kg^{-1}$) > Soil A ($8.1g\;kg^{-1}$). Inorganic-N concentration also differed significantly among soils, decreasing in the order of Soil B > Soil C > Soil A. Degree of P saturation (DPS) of Soil C was 178%, about three and fifteen times of Soil B (38%) and Soil A (6%). Prior to treatment, soils in lysimeters (dia. 300 mm, soil length 450 mm) were tabilized by repeated drying and wetting procedures for two weeks. After urea at $150kg\;N\;ha^{-1}$ and $KH_2PO_4$ at $100kg\;P_2O_5\;ha^{-1}$ were applied on the surface of each soil, total volume of irrigation was 213 mm at seven occasions for 65 days. At 13, 25, 35, 37, and 65 days after treatment, soil solution was sampled using rhizosampler at 10, 20, and 30 cm depth and leachate was sampled by free drain out of lysimeter. The volume of leachate was the highest in Soil C, and followed by the order of Soils A and B, whereas the amount of leached nitrate had a reverse trend, i.e. Soil B > Soil A > Soil C. Soil A and B had a significant increase of the nitrate concentration of soil solution at depth of 10 cm after urea-N treatment, but Soil C did not. High nitrate mobility of Soil B, compared to other soils, is presumably due to relatively high clay content, which could induce high extraction of nitrate of soil matrix by anion exclusion effect and slow rate of water flow. Contrary to Soil B, high organic matter content of Soil C could be responsible for its low mobility of nitrate, inducing preferential flow by water-repellency and rapid immobilization of nitrate by a microbial community. Leached phosphate was detected in Soil C only, and continuously increased with increasing amount of leachate. The phosphate concentration of soil solution in Soil B was much lower than in Soil C, and Soil A was below detection limit ($0.01mg\;L^{-1}$), overall similar to the order of degree of P saturation of soils. Phosphate mobility, therefore, could be largely influenced by degree of P saturation of soils but connect with apparent leaching loss only more than any threshold of P accumulation.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.172-182
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• 2006

This study was designed to assess molinate fate in the lysimeter by measuring the total radioactivity in the leachate, evolved $^{14}CO_2$, and $^{14}C$-residues in soil and rice plant. The amounts of applied $^{14}C$ in the leachate from the lysimeter for 20 weeks were 1.05% in 2.31 pore volume (217,465 mL) at the first and 0.34% in the second year, respectively. The amount of $^{14}CO_2$ evolved from the lysimeter accounted for 6.47% and 0.03% of applied $^{14}C$ in the first and second year. The $^{14}C$-activities in the soil layer of the lysimeter were distributed 18.0% (1st) and 13.3%(2nd) in the depth of 0 to 10 cm, 4.3 (1st) and 1.1% (2nd) in the depth of 10 to 20 cm. Most of the applied $^{14}C$ was detected in the top 20 cm soil layer. Total $^{14}C$ in rice plants grown at lysimeter were detected 11.46% of applied $^{14}C$. 11.11% in straw, 0.24% in brown rice grain, 0.08% in chaff and 0.03% in ears were distributed in the first year. Consequently, environmental fate of molinate using lysimeter simulating a paddy rice field were investigated 25.24% in soil, 11.64% in rice plant, 1.05% in leachate, 6.74% in evolved $^{14}CO_2$ and 0.02% in volatilized organic chemicals in the first year.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.1 no.1
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• pp.41-46
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• 2003

To understand the long-term leach behavior of a borosilicate Waste glass in a repository, the leaching experiment with three kinds of simulated borosilicate waste glasses has been carried out since the middle of 1997. The five years results indicate that a boron would be applied as an indicator of a long-term leaching of their borosilicate waste glasses and that their long-term leach rates have a tendency to be close to about 0.03g/$m^2$-day even though their compositions and their ratios of the surface area to the volume of leachate are different.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.244-250
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• 2003

With a recent public concern rising on the radioactive waste, it is disclosed that the problem is more serious than expected. This research has been conducted to find effects of yellow sandy rainwaters on the solidified cement of mid-and-low level radioactive waste. The ANS 16.1 standard test method was chosen for this leaching experiment. Make a cement solidified radioactive waste that contains Co nuclide, and fabricate it for over 28 days. Then, decide on the volume of leaching water and the concentration of ion and metal in leachate from the mass concentration of yellow sands in atmosphere. In this paper, we have taken a short look at characteristics of yellow sand. Before going into the leaching experiment, we decided experimental conditions first. Then, it was evaluated and analyzed how sandy rainfalls have impact on the cement solidified radioactive waste based on data from 90 days of leaching experiment.

• Journal of Drive and Control
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• v.11 no.4
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• pp.46-52
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• 2014

This study suggests a small-sized screw decanter specialized for dredging sites. Generally, conventional screw decanters are composed of a cylinder and a cone. However, the suggested screw decanter simply has a cone based on a cone-type bowl structure. In this research, a commercial analysis tool is used to establish an optimal design for the bowl and the screw conveyor. Moreover, the base frame, where the main bearings that support the spindle of the bowl and the screw conveyor are installed, is optimally designed considering the weight of the rotating body and the deflection caused by the high centrifugal force. Furthermore, the natural frequency range of the spinning body, the bowl and the screw conveyor, is applied to this base frame; it is designed not to correspond to the resonance frequency range and achieves stability as a result. This study suggests an optimal design for the rotating body and the base frame of a screw decanter considering its vibration characteristics. Such a design will prevent overuse of materials and help to reduce the weight and volume-and the price-of a screw decanter.