Jongro gu, South Korea
Jongro gu, South Korea

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Neculita C.M.,Korea Advanced Institute of Science and Technology | Yim G.-J.,Korea Institute of Geoscience and Mineral Resources | Lee G.,Korea Advanced Institute of Science and Technology | Ji S.-W.,Korea Institute of Geoscience and Mineral Resources | And 3 more authors.
Chemosphere | Year: 2011

Bioreactors are one possible best sustainable technology to address the mine-impacted water problems. Several prospective substrates (mushroom compost, cow manure, sawdust, wood chips, and cut rice straw) were characterized for their ability to serve as a source of food and energy for sulfate-reducing bacteria. Twenty bench-scale batch bioreactors were then designed and set up to investigate relative effectiveness of various mixtures of substrates to that of mushroom compost, the most commonly used substrate in field bioreactors, for treating mine drainage with acidic (pH 3) and moderate pH (pH 6). Overall, reactive mixtures showed satisfactory performances in generating alkalinity, reducing sulfate and removing metals (Al. > Fe. > Mn) (up to 100%) at both pH conditions, for all substrates. The mixture of sawdust and cow manure was found as the most effective whereas the mixture containing 40% cut rice straw gave limited efficiency, suggesting organic carbon released from this substrate is not readily available for biodegradation under anaerobic conditions. The mushroom compost-based bioreactors released significant amount of sulfate, which may raise a more concern upon the start-up of field-scale bioreactors. The correlation between the extent of sulfate reduction and dissolved organic carbon/. SO42- ratio was weak and this indicates that the type of dissolved organic carbon plays a more important role in sulfate reduction than the absolute concentration and that the ratio is not sensitive enough to properly describe the relative effectiveness of substrate mixtures. © 2010 Elsevier Ltd.

Ok Y.S.,Kangwon National University | Kim S.-C.,Kangwon National University | Kim D.-K.,Kangwon National University | Skousen J.G.,West Virginia University | And 4 more authors.
Environmental Geochemistry and Health | Year: 2011

The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg-1) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils. © 2010 Springer Science+Business Media B.V.

Lee Y.-G.,Sungkyunkwan University | Han J.,Siloam Biosciences, Inc. | Kwon S.,Mine Reclamation Corporation | Kang S.,Kyung Hee University | Jang A.,Sungkyunkwan University
Chemosphere | Year: 2016

Atomic absorption spectrometry and inductively coupled plasma-mass spectrometry are widely used for determination of heavy metals due to their low detection limits. However, they are not applicable to on-site measurements of heavy metals as bulky equipment, and highly skilled laboratory staffs are needed as well. In this study, a novel analytical method using a rotary disc voltammetric (RDV) sensor has been successfully designed, fabricated and characterized for semi-continuous and on-site measurements of trace levels of Pb(II) in non-deoxygenating solutions. The square wave anodic stripping voltammetry was used to improve the sensitivity of the Pb(II) detection level with less than 10nM (2μgL-1). The RDV sensor has 24-sensing holes to measure concentrations of Pb(II) semi-continuously at sampling sites. Each sensing hole consists of a silver working electrode, an integrated silver counter, and a quasi-reference electrode, which requires only a small amount of samples (<30μL) for measurement of Pb(II) without disturbing and/or clogging the sensing environment. In addition, the RDV sensor showed a correlation coefficient of 0.998 for the Pb(II) concentration range of 10nM-10μM at the deposition time of 180s and its low detection limit was 6.19nM (1.3μgL-1). These results indicated that the advanced monitoring technique using a RDV sensor might provide environmental engineers with a reliable way for semi-continuous and on-site measurements of Pb(II). © 2015 Elsevier Ltd.

Lee E.-J.,Sungkyunkwan University | Kwon J.-S.,Hyundai Engineering | Park H.-S.,Mine Reclamation Corporation | Ji W.H.,Mine Reclamation Corporation | And 2 more authors.
Desalination | Year: 2013

Many attempts have been made to control fouling in membrane bioreactors (MBRs) to sustain permeability through relaxation, backwashing and chemical cleaning. Sodium hypochlorite is one of the most useful chemical agents used to control fouling in chemically enhanced backwashing (CEB) of MBRs. However, sodium hypochlorite has the potential to adversely affect microorganisms because CEB is usually carried out within the bioreactor. Hence, this study investigated how sodium hypochlorite influences activated sludge from the viewpoint of microorganism properties and suggests the limit of sodium hypochlorite dosage. Activated sludge was evaluated using the substance removal rate, extracellular polymeric substances (EPSs), particle size distribution (PSD) and permeability. It was shown that 1mg-NaOCl/g-MLVSS had a slight superiority in nutrient removal compared to 5mg-NaOCl/g-MLVSS. On the other hand, the NH4-N removal ratio of 1mg-NaOCl/g-MLVSS was bigger than that of 5mg-NaOCl/g-MLVSS in nitrification for 3h from the time of sodium hypochlorite addition. While 1mg-NaOCl/g-MLVSS showed a similar tendency with the reference sludge in the case of EPSpolysaccharide, 5mg-NaOCl/g-MLVSS generated EPSpolysaccharide 1.5 times as much as that of 1mg-NaOCl/g-MLVSS. Also, according to particle size distribution, the average floc size of 5mg-NaOCl/g-MLVSS was changed from 43.63 to 36.98μm. As a result, the sludge of 5mg-NaOCl/g-MLVSS had a much higher potential for increase than the reference sludge in membrane fouling. Moreover, a microfiltration experiment confirmed that 5mg-NaOCl/g-MLVSS had a double rate increase of resistance compared with 1mg-NaOCl/g-MLVSS. © 2013 Elsevier B.V.

Lee S.-H.,Mine Reclamation Corporation | Kim E.Y.,Mine Reclamation Corporation | Park H.,Korea Ocean Research and Development Institute | Yun J.,Korea University | Kim J.-G.,Korea University
Geoderma | Year: 2011

The usefulness of limestone, red mud, and furnace slag on the in situ stabilization of arsenic (As) and heavy metals was evaluated relative to different endpoints (microorganisms, plants, and humans). Individually or combined treatment of iron-rich amendments were effectively lowered the availability of trace elements. Compared to control soil, Ca(NO3)2-eatractable As, Cd, Pb, and Zn was reduced by 58%, 98%, 98%, and 99%, respectively, by combined treatment of limestone and red mud. The decreased availability of trace elements was accompanied by increased microbial activity (respiration, glucose mineralization, and soil enzyme activity) and decreased plant uptake of trace elements. Compared to non amended control soil, only 13%, 28%, 47%, and 12% of the As, Cd, Pb, and Zn, respectively, detected in combined treatment of limestone and red mud. These results suggest that iron-rich industrial by-products could be used for remediation of soils co-contaminated with metals and arsenic. © 2010 Elsevier B.V.

Lee S.-H.,Mine Reclamation Corporation | Park H.,Korea Ocean Research and Development Institute | Koo N.,Korea University | Hyun S.,Korea University | Hwang A.,Korea University
Journal of Hazardous Materials | Year: 2011

We evaluated the effects of five different kinds of amendments on heavy metals stabilization. The five amendments were: zero valent iron, limestone, acid mine drainage treatment sludge, bone mill, and bottom ash. To determine bioavailability of the heavy metals, different chemical extraction procedures were used such as, extraction with (Ca(NO3)2, DTPA; toxic characteristic leaching procedure (TCLP), physiologically based extraction test (PBET) that simulates gastric juice, and sequential extraction test. Bioavailability was also determined by measuring uptake of the heavy metals by lettuce (Lactuca sativa L.) and earthworms (Eisenia fetida). In addition, dehydrogenase activity was measured to determine microbial activity in the soil with the different amendments. The addition of amendments, especially limestone and bottom ash, resulted in a significant reduction in extractable metal contents. Biological assays using lettuce, earthworm, and enzyme activity were found as appropriate indicators of available metal fraction after in situ stabilization of heavy metals. In conclusion, TCLP and sequential extraction test appear to be promising surrogate measure of metal bioavailability in soils for several environment endpoints. © 2011 Elsevier B.V.

Koo N.,Korea University | Jo H.-J.,Korea Institute of Science and Technology | Lee S.-H.,Mine Reclamation Corporation | Kim J.-G.,Korea University
Journal of Hazardous Materials | Year: 2011

The effects of iron (Fe) and spent mushroom substrate (SMS) arsenic (As) phytotoxicity towards lettuce in artificial soils were investigated to separate the adverse soil parameters relating to As toxicity using a response surface methodology. SMS induced the root elongation of lettuce in both control and As-treated soils. However, in phytotoxicity test using a median effective concentration (EC50) of As, Fe and the interaction between both parameters (Fe SMS) significantly affected EC50, which explained 71% and 23% of the response, respectively. The refined model was as follows: EC50 of As (mgkg-1)=10.99+60.03×Fe-10.50×Fe SMS. The results confirmed that the soil parameters relating to the As mobility in soils were important factors affecting its toxicity. In conclusion, Fe significantly reduced the As phytotoxicity. However, although SMS enhanced the root elongation, SMS in As-treated soils decreased EC50 of As on the root growth via its interaction with Fe. Despite the limitations of the artificial soils and range of parameters studied, the application of this statistical tool can be considered a powerful and efficient technique for interpretation and prediction of the complicated results caused by the interactions between many factors within the soil environments. © 2011 Elsevier B.V.

Koo N.,Korea University | Lee S.-H.,Mine Reclamation Corporation | Kim J.-G.,Korea University
Environmental Geochemistry and Health | Year: 2012

The objectives of this study were to elucidate the effects of soil amendments [Ferrous sulfate (Fe II), red mud, Fe II with calcium carbonate (Fe II/L) or red mud (RM/F), zero-valent iron (ZVI), furnace slag, spent mushroom waste and by-product fertilizer] on arsenic (As) stabilization and to establish relationships between soil properties, As fractions and soil enzyme activities in amended As-rich gold mine tailings (Kangwon and Keumkey). Following the application of amendments, a sequential extraction test and evaluation of the soil enzyme activities (dehydrogenase and β-glucosidase) were conducted. Weak and negative relationships were observed between water-soluble As fractions (As WS) and oxalate extractable iron, while As WS was mainly affected by dissolved organic carbon in alkaline tailings sample (Kangwon) and by soil pH in acidic tailings sample (Keumkey). The soil enzyme activities in both tailings were mainly associated with As WS. Principal component and multiple regression analyses confirmed that As WS was the most important factor to soil enzyme activities. However, with some of the treatments in Keumkey, contrary results were observed due to increased water-soluble heavy metals and carbon sources. In conclusion, our results suggest that to simultaneously achieve decreased As WS and increased soil enzyme activities, Kangwon tailings should be amended with Fe II, Fe II/L or ZVI, while only ZVI or RM/F would be suitable for Keumkey tailings. Despite the limitations of specific soil samples, this result can be expected to provide useful information on developing a successful remediation strategy of As-contaminated soils. © 2011 Springer Science+Business Media B.V.

Nam S.M.,Korea University | Kim M.,Korea University | Hyun S.,Korea University | Lee S.-H.,Mine Reclamation Corporation
Chemosphere | Year: 2010

The chemical attenuation of As by soils from abandoned mine sites was evaluated. Several soil samples, including As contaminated soil from the mine impacted areas, as well as As-free soils down-gradient from the mine sites, were collected across abandoned mine sites. Leaching and adsorption experiments were conducted under batch and 1-D water flow conditions. The cumulative As mass from 10 step sequential leaching experiments with six As contaminated soils, using 10mM CaCl2 solution, was less than 1% of the total As present in soils, indicating that As in contaminated soils is strongly adsorbed onto soil particles, which can serve as a long term potential As source. As adsorption by As-free soils was clearly nonlinear, with Freundlich N values (sorption nonlinearity) ranging from 0.56 to 0.87. Both the total As content in mine soils and the concentration-specific adsorption coefficient for arsine-free soils were best described by coupling the pH with various forms of Fe/Al oxides. In the breakthrough curves (BTCs) for As contaminated soils, an initial high concentration of As (called first-flush) was observed, and this flush export leveled off after the displacement of a few pore volumes. In the BTCs from layered soils, where clean down-gradient soils were overloaded above the mine soil, the appearance of measurable As was retarded, showing that the As attenuation by soils was effective in a flow water system. Also, the observed perturbation in the concentration of As during flow interruption supports that leaching/attenuation of As via flowing water occurs under nonequilibrium conditions. The results from both batch leaching/adsorption and column displacement experiments strongly suggested that the leaching of As from mine soils was rate limited and the risk of As leaching from soils can be mitigated by attenuation mechanisms, such as adsorption, provided by down-gradient clean soils. © 2010 Elsevier Ltd.

Seo H.,Mine Reclamation Corporation | Seo H.,Pukyong National University | Lee M.,Pukyong National University | Wang S.,Pukyong National University
Environmental Engineering Research | Year: 2013

Biocarrier beads with dead biomass, Bacillus drentensis, immobilized in polymer polysulfone were synthesized to remove heavy metals from wastewater. To identify the sorption mechanisms and theoretical nature of underlying processes, a series of batch experiments were carried out to quantify the biosorption of Pb(II) and Cu(II) by the biocarrier beads. The parameters obtained from the thermodynamic analysis revealed that the biosorption of Pb(II) and Cu(II) by biomass immobilized in biocarrier beads was a spontaneous, irreversible, and physically-occurring adsorption phenomenon. Comparing batch experimental data to various adsorption isotherms confrmed that Koble-Corrigan and Langmuir isotherms well represented the biosorption equilibrium and the system likely occurred through monolayer sorption onto a homogeneous surface. The maximum adsorption capacities of the biocarrier beads for Pb(II) and Cu(II) were calculated as 0.3332 and 0.5598 mg/g, respectively. For the entire biosorption process, pseudo-second-order and Ritchie second-order kinetic models were observed to provide better descriptions for the biosorption kinetic data. Application of the intra-particle diffusion model showed that the intraparticle diffusion was not the rate-limiting step for the biosorption phenomena. Overall, the dead biomass immobilized in polysulfone biocarrier beads effectively removed metal ions and could be applied as a biosorbent in wastewater treatment. © Korean Society of Environmental Engineers.

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