• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.57-67
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• 2001

The purpose of this study is to predict appropriate leachate rates and leachate transport velocity through weathered zone and basement rock on the transient condition at Nanji waste landfill. The leachate transport in the Nanji waste landfill is analyzed using MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model) model which simulates three dimension groundwater flow and MT3D(A Modular Three Dimentional Transport Model) model which describes three dimensional transport for advection, dispersion and chemical reaction of dissolved constituents in groundwater system on the transient condition. Leachate production rates are estimated by HELP(Hydraulical Evaluation of Landfill Performance) model and used weather records for recent 10 years. Leachate transport is predicted by a change of leachate level to after/before established HDPE, established slurry wall and wells.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.11a
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• pp.102-105
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• 1996

난지도 매립지는 매립충의 불균질성과 고온의 침출수 및 가스의 흐름이 동시에 복합적으로 일어나는 현상 때문에 수리지질학적으로 매우 복잡한 지역이다. 난지도의 수문층서단위 조사와 디스크-장력 침투계(Disc tension Infiltrometer)로 불포화대 수리 특성을 추정하였으며 가스 거동 현상을 이해하기 위해 지온을 측정하였다. 매립지 주변의 지하수위 변화를 조사하기 위해 양수정과 다중-수위관측정(Multi-Level Monitoring Well)에서 수위변화를 관측하였다. 불포화대 수리특성과 기상자료를 바탕으로 매립지로의 순침투량을 추정하였다. 이것을 근거로 총 침출수 발생량을 추정하였으며, 기저 지하수면 상부에 분포하는 포화 침출수대, 즉 부유침출수의 생성 메카니즘에 대한 연구도 수행하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.12a
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• pp.41-54
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• 1996

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.427-434
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• 2013

The leachate from landfill (Andong city) contaminated by foot-and-mouth disease (FMD) contains 44%-50% hydrophilic organic matter, compared with 22%-27% in natural water bodies such as ground water, lake water, and river water. In such natural water, the organic matter content is reduced by the metabolism of microbes in the water. However, in the case of leachate-1 and -2, the concentrations of RTOC (refractory total organic carbon) and RDOC (refractory dissolved organic carbon) were higher than the initial TOC and DOC after burial. According to time elapsed after burial, the concentrations of RTOC and RDOC were decreased below the initial TOC and DOC. In the case of leachate-6 (386 days after burial), RDOC made up 91% of RTOC. This result shows that organic matter in the leachate was composed dominantly of RDOM, most of which was not removed by the metabolism of microbes. Hence, the presence and characteristics of RDOM provide a valuable indication of the effect of leachate on the quality of surface water and ground water. Such information is useful in understanding leachate environments.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.21-31
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• 2003

IAEA, FT-04-020, and ANS 16.1, standard leaching test methods, were evaluated comparatively with their test results. Leaching index of Co-60 and Cs-137 for all waste forms were above 6.0. Their leaching behavior were contrary according to the type of matrix and leachant. Leachability of Co in cement waste form was higher in simulated seawater than demi. water, and higher in demi. water in paraffin waste form. Leachability of Cs was contrary to Cs. Cumulative fraction leached of Co was higher such as IAEA＞ANS＞FT in cement waste form.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.107-117
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• 2001

The characteristics of groundwater movement under the heavy rainfall at Nan-ji waste landfill site are studied using HELP(Hydraulic Evaluation of Landfill Performance) program, which calculates the daily leachate in the Nan-ji waste landfill site. In this study, instead of the average recharge value, which is used in the past study, the real reacharge value is used to calculate the daily leachater. It is found about 70 times greater than thor average recharge value under the condition of heavy rainfall in the rainy season. The flow characteristics of groundwater for water level fluctuation is simulated using the ground water flow model MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model) program, and the slurry layer is newly added. The result of the study is different from that of the ordinary simulation, which shows much higher ground water level than from the ordinary simulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5C
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• pp.217-228
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• 2009

In case of application of electrophoresis method for leakage restoration of waste impoundment, main points of consideration were to evaluate the mobility of clay particles by electrophoretic force and capacity of leakage repair in leachate electrolyte system contained with various chemical species. However, the flocculation phenomena of clay particles induced by electrochemical interaction between various chemical species and clay particles would cause the big problems in electrophoresis method. Therefore, a series of laboratory tests such as one-dimensional electrophoresis and gravitational experiments were carried out in order to identify the specific chemical species affected flocculation of clay particles and the range of chemical concentration in leachate. In addition, the characteristics of clay particle behavior with chemical species and concentration range in leachate were analized using the concept of the settling velocity, zeta potential, and electrophoretic velocity.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.24-31
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• 2005

In order to recover valuable metals from fine-grained electronic waste, bioleaching of Cu, Zn, Al, Co, Ni, Fe, Sn and Pb were carried out using Aspergillus niger as a leaching microorganism in a shaking flask. Aspergillus niger was able to grow in the presence of electronic scrap. The formation of organic acids(citric and oxalic acid) from Aspergillus niger caused the mobilization of metals from waste electronic scrap. In a preliminary study, in order to obtain the data on the leaching of Cu, Zn, Al, Fe, Co and Ni from electronic scrap, chemical leaching using organic acid(Citric acid and Oxalic acid) was accomplished. At the electronic scrap concentration of 50 g/L, Aspergillus niger were able to leach more than 95% of the available Cu, Co. But Al, Zn, Pb and Sn were leached about 15-35%. Ni and Fe were detected in the leachate less than 10%.

• 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.

• Resources Recycling
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• v.31 no.2
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• pp.56-62
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• 2022

This study investigated the water leaching behavior of vanadium in Na₂CO₃-roasted vanadium-bearing titaniferous magnetite (VTM) concentrate. The magnetic concentrate and Na₂CO₃, mixed in a mass ratio of 4:1, were roasted at 1050 ℃, kept for 3 h, and ground to a size of D₅₀ = 48.79 ㎛ using a rod mill. The effects of leaching temperature and pulp density on water leaching were then investigated. The results show that the vanadium leaching efficiency decreased to 90.4%, 88.2%, and 83.8% as the temperature increased to 25, 55, and 85 ℃, respectively, whereas it remained almost constant 90.4%, 87.0%, and 87.0% as the pulp density increased to 10, 50, and 100 w/v%, respectively. Based on the preliminary leaching results, multi-stage leaching was conducted with the experimental conditions of 25 ℃, 100 w/v%, 300 rpm, and 1 h. The vanadium concentration in the final leaching solution was determined as 16.20 g/L after four stages of leaching. Thus, a high-concentration sodium vanadate solution was prepared by multi-stage leaching.