• Journal of Wetlands Research
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• v.17 no.1
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• pp.38-44
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• 2015

In Korea, most rainfall events occur during summer which then leads to an increasing concern regarding high influx of non-point source pollutants since the pollutant loadings from these non-point sources are very significant. In particular, the first flush of roof-harvested rainfall is said to contain the most highest concentration of nutrients and heavy metals. Accordingly, it is important to develope the possible water quality management options in treating the contaminants and considering reclaimed water reuse. The rain garden could be one of suitable alternatives in addressing this issue. In this study, the development of an effective adsorption media and its application to a lab-scale rain garden was tested to evaluate the removal rate of various nutrient and organic matter (TN, TP, CODcr), and heavy metals (Cu, Cd, Pb). Results showed that carbonized peatmoss produced at higher temperature have better adsorption capacity as compared to the one produced at a lower temperature. When the carbonized peatmoss was applied as rain garden media, the highest removal of TN, TP, and CODcr was observed compared to no carbonized peatmoss applied rain garden. Therefore, this study showed that the carbonized peatmoss would be effectively applied to the rain garden for removing nutrients and heavy metals from roof-harvested rainwater.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.257-262
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• 2008

In the study it was investigated the diffusion characteristics of heavy metal pollutions such as Cu, Pb, Hg and As which was the main pollution sources of soils from abandoned mines. The pollution of Cu and Pb was caused by Mine A, that of Hg was caused by Mine 3, that of Pb was caused by Mine C and that of Cu, Pb, As was caused by Mine D. Though the high concentration was detected within 100m from abandoned mines, the low concentration was detected over than 100m from abandoned mines in all heavy metals investigated except As. It means that it was very difficult to estimate the pollution level of As caused abandoned mines. The results were discussed in the concentrations of Cu, Pb and distances showed a good relationship with 0.71 and 0.68 as the coefficient of correlation, respectively. In particular the relativity of Cu to Pb as very strong with 0.84 as the coefficient of correlation. It was consistent with the chemical behavior in soils in the case of Cu and Pb. Therefore it will be a promising approach to remove Cu and Pb with estimated values in the study.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.130-137
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• 2005

This research programme include investigation of the adsorption behavior of heavy metals and VOCs by Pyrolysis char for using landfill cover material. The volatile potions in the sludge gasified during the pyrolysis period and gave birth to porosity throughout the matrix. The result of the ad/desorption experiment of nitrogen to find out the formation of some pore by the gasification of the volatile matter, we can certify that the pyrolysis char($14.56\;m^2/g$) has increased twice more than the organic wasted sludge($6.68\;m^2/g$) in specific surface area. The pyrolysis char has the adsorption characteristic of medium type of Type II and V in BDDT classification, and showed a little micro pore. In the adsorption experiment of ethylbenzene and toluene, as a result of applying the Freundlich adsorption isotherms, the pyrolysis char was higher in the adsorptivity of ethylbenzene and toluene than the granite and the organic wasted sludge. The results of the heavy metal adsorption test for the char indicated that it had some ability of adsorption. It is suggest that pyrolysis char has some advantages for utilizing as landfill covers because the pyrolysis char can adsorb/absorb hazardous substances from the landfill sites and inhibit the ground water and soil contamination.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.720-728
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• 2012

In general, nonpoint pollutant of a watershed is drained out in the form of storm water runoff during rainfall events. As the bulk of the nonpoint pollutant is in adsorbed form on particulate matters, in order to understand the behavior of nonpoint pollutant it is essential to grasp the characteristics of particulate matters in rainfall runoff. Though, previous studies for the relationship between the runoff characteristics of pollutants and the size distribution of particulate matters are very rare. In this study, a small non-urbanized area (basin area of 52.8 ha) with various landuse types including paddy, dry fields and forest was selected and investigated in detail for the runoff properties of each pollutant during several rainfall events. The correlation and effects between particulate matters and nonpoint pollutant were analyzed quantitatively. As a result, the significant first flush was observed on each event and it became clear that fine particulate matters ($80{\mu}m$ or less) has contributed in the runoff process of nutrients and heavy metals. Organic matters ($BOD_5$, TOC), nutrients (TN, TP) and several heavy metals (Al, Cr, Cu, Fe, Hg and Zn) represented high correlations with SS (total), VSS, SS (d < $20{\mu}m$) and SS ($20{\mu}m$ $$\leq_-$$ d < $80{\mu}m$). On the other hand, $COD_{cr}$, Cd, Mn and Pb did not show clear correlations with the behavior of particulate matters. Therefore, we have to examine the introduction of nonpoint pollution mitigation facilities considering the facts that nonpoint pollutant runoff process has high correlation with the behavior of particulate matters and is changeable based on the target pollutants.

• Economic and Environmental Geology
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• v.41 no.2
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• pp.183-199
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• 2008

This study is focused on characterization of the physio-chemical and mineralogical properties, investigation of their vertical changes in the tailing profile of the Guryoung mining area, classification of the profile into distinct zones, and condition conceptual model of physio-chemical conditions and phases-water relationships controlling the element behaviors in the tailings. The upper part of the groundwater is characterized by the high contents of $Fe_2O_3$ and $SO_3$ for whole rock analysis, low pH, and the occurrence of jarosite, schwertmannite and Fe-oxyhydroxide as the secondary mineral phases. The tailing profile can be divided into the covering soil, jarosite zone, Fe-sulfate zone, Fe-oxyhydroxide and gypsum-bearing pyrite zone, calcite-bearing pyrite zone, soil zone, and weathered zone on the based of the geochemical and mineralogical characteristics. The profile can be sampled into the oxidized zone and the carbonate-rich primary zone with the dramatic changes in pH and the secondary mineral phases. The conceptual model proposed for the tailing profile can be summarized that the oxidation of pyrite is the most important reaction controlling the changes in pH, the dissolution of the primary silicates and carbonates, the precipitation of secondary mineral phases, acid-neutralizing, and heavy metal behaviors through the profile.

• Resources Recycling
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• v.18 no.2
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• pp.69-76
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• 2009

Alumina powder was prepared from heat-treatment of artificial marble waste fine aggregate containing $Al(OH)_3$ for the purpose of the feasibility of its recycling. Artificial marble waste was heat-treated between $500^{\circ}C$ and $1000^{\circ}C$ and XRD, BET surface area, BJH pore size distribution and adsorption of As were analyzed for heat-treated powder. It was found that the adsorption efficiency of As was significantly affected by phase composition of alumina powder rather than its physical characteristic. Heat-treated powder compact was sintered to produce the pellet. Alumina pellet with porosity more than 60% could be obtained after sintering below $1200^{\circ}C$ and also the addition of glass powder as a sintering aid had a positive effect on lowering sintering temperature, led to the high porosity near 60% and adsorption of As over 60% even at $900^{\circ}C$.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.1
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• pp.41-53
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• 1997

Geochemical data of soil and water samples were presented in order to assess the environmental impart for drinking water sites. Microscopic observation of rock samples and physical and chemical analysis of soil and water samples were undertaken. The geology of study areas are classified into three groups such as granitic rocks, meta-sedimentary rocks and sedimentary rocks. Enrichment of heavy metals derived from those rocks is not found in this study areas. Soils were analyzed for Cu, Pb, Zn, Cd and Cr using AAS extracted by HNO$_3$+HClO$_4$ and 0.1 N HCl. Heavy metal concentrations in soils are within the range of those in uncontaminated soils. In comparison of metal contents extracted by 0.1 N HCl and HNO$_3$+HC1O$_4$, less than 10% of the heavy metals are present in the exchangeable fraction. In particular, an pollution index has been proposed to assess the degree of soil contamination. Pollution index in soils are between 0.03 and 0.47 therefore, soils are not polluted with heavy metals. Deep groundwaters within granitic rocks have been evolved into Na$\^$＋/-HCO$_3$$\^$-/ type, whereas other deep groundwaters evolved into Ca$\^$2＋/-HCO$_3$$\^$-/ type. The predominance of Na$\^$＋/ over Ca$\^$2＋/ in deep groundwaters within granitic rocks is a result of dissolution of plagioclase, but for sedimentary and meta-sedimentary rocks, dissolution of calcite is a dominant factor for their hydrogeochemistry. The pH, conductivity and contents of the most dissolved ions in the water increase with depth. Shallow groundwaters, however, are highly susceptible to pollution owing to agricultural activities, considering the fact that high contents of nitrate, chloride and potassium, and high K/Na ratio are observed in some shallow groundwaters. In a thermodynamic approach, most natural water samples are plotted within the stability fields of kaolinite and smectite. Therefore, microcline and other feldspars will alter to form clay minerals, such as kaolinite and smectite. From the modelling for water-rock interactions based on mass balance equation, models accord well with behavior of the ions and results of thermodynamic studies are derived.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.331-339
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• 2008

In the upstream of Nakdong river in Bonghwa-gun, Gyeongsangbuk-do, certain areas of riverside were found to be covered by weathered mine tailings which were assumed to be migrated and deposited by flood. This study was conducted to investigate the formation and characteristics of the secondary minerals from tailings and related leaching behavior of heavy metals in the severely weathered tailing deposits by river waters. Quartz, feldspar, micas, chlorite, hornblende, talc, pyroxene (johannsenite), pyrite, and calcite were identified as primary minerals by XRD. Kaolinite can be formed by the weathering of tailings, but considering the short period of weathering time, kaolinite in the deposits is considered to be from unweathered tailings or moved from soils. The secondary minerals such as goethite, gypsum, basanite, and jarosite were also identified. The formation of the secondary minerals was affected by the species of primary minerals and pH conditions. The weathering of pyrite produced sulfate minerals such as gypsum, basanite, jarosite, and also goethite. Mn oxide was also identified by SEM, coated on the primary minerals such as quartz. This Mn oxide was poorly crystalline and thought to be the weathering product of johannsenite (Mn-pyroxene). The Fe and Mn oxides are the main minerals determining the brown/red and black colors of weathered tailings. EDS results showed that those oxides contain high concentrations of Pb, Zn, and As, indicating that, in the river, the formation of Fe and Mn oxides can control the behavior and leaching of heavy metals by co-precipitation or adsorption.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.201-210
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• 2000

Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mats. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributons. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks dial not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the $K_{I}$ vague increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.s.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.447-456
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• 2000

Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mass. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributions. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks did not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the K$_1$ value increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.