• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.945-950
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• 2007

The stormwater runoff from paved area are highly polluted because of particulate materials as well as metals from various vehicular activities. The Division of Road Maintenance in Ministry of Construction and Transportation was recently developed the Guidelines of Environment-kindly Road Maintenance. It is actually requiring the BMP construction to control the nonpoint source pollution as based on the TMDL program. This research is carried out in order to define the characteristics of stormwater runoff from the toll-gate of highways since 2006, which is actually one of the main pollutant sources of paved areas. This monitoring is the first phase work for establishing the treatment facilities in the toll-gates. The one of the main characteristics from toll-gate runoff is the first flush phenomenon containing lots of sediments and metal compounds at the beginning of a storm event. Usually it is used to determine the size of treatment facilities and to calculate the reduced pollutant mass in the facility. The research results shows that the mean EMC vaules for heavy metals are determined to $274.3{\mu}g/L$ for Cd, $1,273.4{\mu}g/L$ for Cr, $1,822.0{\mu}g/L$ for Cu, $6,504.9{\mu}g/L$ for Fe, $14,930.3{\mu}g/L$ for Pb, and $714.1{\mu}g/L$ for Zn. Also the metal mass loadings from the toll-gates are calculated using EMC, watershed area and storm duration.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.445-455
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• 2009

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfate-reducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides. Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.32-37
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• 2005

The soil properties of the royal tombs (managed by cultural properties administration) located in Seoul and suburban Gyonggi area were investigated to see the influence of the change in soil environment on the royal tomb s이I. To compare the soil chemical properties of four royal tombs soil of Changdeokgung, Jongmyo, Seooneung, and Dongguneung, pH, organic content, available phosphate, extractable calcium, extractable potassium, extractable magnesium, cation exchange capacity, degree of base saturation, and total nitrogen content were measured. The concentrations of Cd, Pb, and Cu measured as the degree of heavy metal contamination can be an indication of atmospheric pollution in the soil environment. To estimate the degree of soil compaction, soil hardness, pore space, porosity, bulk density, and soil atmosphere were analyzed. Through these studies, following conclusions were made: 1. The soil hardness and pore space which can be used as indexes of soil compaction, were worse in the soil of Seooneung than in those of Changdeokgung and Dongguneury. These phenomena seem to be the result of increase in visitors in Seooneung and Dongguneung better and soil management in Changdeokgung and Dongguneung. When three different regions of forest area, prohibited area, and soil compaction area in Seooneung soil were compared, the degree of compaction in the forest area was less than compaction area, indicating the need for the employment of soil resting period in the compaction area. 2. The pH measurements of all four royal tombs soil were higher in top soil than sub soil. The higher soil pH values in Jongmyo and Seooneung seem to result from the application of soil conditioner. In the case of Seooneung, the values for soil pH and organic content were higher in the forest area than those in compaction area. It is thought that active soil management was employed in the forest area through application of organic matters and soil conditioners. 3. The heavy metal contents from soil of Changdeokgung and Jongmyo were higher than that from soil of Dongguneung. Since Changdeokgung and Jongmyo are located inside Seoul, it is thought that the high level of heavy metal concentrations in these royal tomb soil is the result of accumulation of pollutants from the city.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1225-1230
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• 2010

본 연구는 군부대 사격장의 중금속 오염토양에 대하여 생물학적 용출기술(BT)과 전기동력학적 기술(ET)의 통합공정의 적용성 평가 연구에 대한 것이다. 사격장 오염 토양의 경우 사격에 의해 탄두가 피탄지에 박히면서 오염토양 내에 잔존하여 탄두를 구성하는 주성분인 납과 구리 등에 의해 지속적인 오염원으로 작용하는 특징을 가진다. 따라서 사격장 토양오염정화를 위해서는 이 탄두를 물리적으로 선별하는 물리적 선별공정을 전처리공정으로 수행한 후 인공적으로 조성된 셀에 통합공정 적용성 평가를 위한 현장실증시험을 수행하였다. 생물학적 용출을 통해 토양내 잔류하는 중금속을 이온화시켜 이동성을 크게 한후 전기동력학적 기술을 통해 토양내에서 전해질로 이동시켜 최종적으로 전해질을 처리하는 시스템으로써 공정 모니터링결과 납과 구리 모두 주목할 만한 제거효율을 얻을수 있었다. 오염물질별 공정 적용성 평가결과 납의 경우 황산화박테리아에 의해 이온화가 되지만 황산화박테리아의 생장 부산물인 황산염이온(${SO_4}^{2-}$)과 반응하여 안정성이 큰 Anglesite($PbSO_4 $)를 형성하므로 전체적인 제거효율이 저하되는 것을 확인하였고 기타 미생물을 이용한 생물학적 용출기술 연구의 필요성을 확인하였다. 구리의 경우 황산염박테리아를 이용한 생물학적 용출공정 및 전기동력학적 처리공정의 통합공정을 통해 주목할 만한 제거효율을 얻을수 있었으며 통합공정의 효율성을 확인할 수 있었다. 본 연구를 통하여 미생물학적 용출기술과 전기동력학적 기술의 통합공정은 현장특이성(Site-specific) 확인후 적용가능성이 있음을 확인하였다.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.173-178
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• 1999

The extracellular cytosine deaminase (EC 3.5.4.1) from Chromobacterium violaceum YK 391 was purified 264.7-fold with an overall yield of 14.3%. The enzyme was for the first time homogeneous by the criteria of polyacrylamide gel electrophoresis performed in the absence and in the presence of sodium dodecyl sulfate. The molecular weight of the purified enzyme was estimated to be about 156 kDa. The enzyme consisted of two identical subunits of approximate molecular weight 78 kDa. The isoelectric point of the enzyme was pH 5.55. The enzyme had a pH optimum of 7.5 and a temperature optimum of around 40 to $45^{\circ}C$. Besides cytosine, the enzyme deaminated 5-fluorocytosine, cytidine, 5-methylcytosine, and 6-azacytosine, but not 5-azacytosine. The extracellular cytosine deaminase is believed to be unique because it was active not only on cytosine but also on cytidine. The apparent $K_m$ values for cytosine, 5-fluorocytosine, cytidine, and 5-methylcytosine were determined to be 1.55 mM, 5.52 mM, 10.4 mM, and 67.2 mM, respectively. The enzyme activity was strongly inhibited by heavy metal ions such as $Fe^{2+},Pb^{2+},Cd^{2+},Zn^{2+}, Hg^{2+}, and Cu^{2+}$ at 1 mM, and completely by $\alpha,\alpha$'-dipyridyl, and $\rho$-chloromercuribenzoate at 1 mM, and weakly inhibited by 1mM ο-phenanthroline. The enzyme activity was not affected by various nucleosides and nucleotides.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.356-361
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• 2013

Lead (II) ion selective poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore as a sulfur containing sensing material is successfully developed. The electrode exhibits good linear response of 25.6 mV / decade (at $20{\pm}0.2^{\circ}C$, r2=0.995) within the concentration range of $1.0{\times}10^{-1}{\sim}4.0{\times}10^{-7}$ M Pb (II). The composition of this electrode was Ionophore : PVC : dioctylphthalate : potassiumtetrakis(4-chlorophenyl)borate : Oleic acid = 5.0 : 20.0 : 25.0 : 4.0 : 5.0. When we consider the results of using different composition electrodes based on only one potassiumtetrakis(4-chlorophenyl)borate or Oleic acid liphophlic additive, poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore with potassiumtetrakis(4-chlorophenyl)borate and Oleic acid liphophlic additive had the best result in response characteristics. The electrode shows good selectivity for lead (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.0 ~ 7.0 and their standard deviation in the measured emf differences was ${\pm}2.94$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-2}$ M and ${\pm}2.82$ mV at Tris buffered lead sample solution of $1.0{\times}10^{-3}$ M. Their stabilization time was less than 710 s. and response time was less than 16 s.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.1-8
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• 2005

Fractional compositions and leaching potentials of Cd, Cu and Zn were investigated in the soils which had been disposed with the metal processing wastes, tungsten mine tailings and low quality coal mine area. Total concentrations of metals in these soils were higher than in non-polluted paddy and upland soils. Fractions of Cd, Cu and Zn were mostly reducible, organic and residual forms, but varied with origins of wastes. Residual fraction was a predominant form in the nonpolluted soils. Leaching potentials of metals were higher in polluted soils than in non-polluted soils. Metals leached were higher at pH 4.0 than 7.0 and increased with the duration time. After 25 to 35 hrs, metals released from soils reached a pseudoequilibrium. Leaching potential of metals in non-polluted soils was low due to high percentage of residual fractions.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.690-698
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• 2012

Cr-B2, a Gram-negative hexavalent chromium [Cr(VI)] reducing bacteria, was isolated from the aerator water of an activated sludge process in the wastewater treatment facility of a dye and pigment based chemical industry. Cr-B2 exhibited a resistance for 1,100 mg/l Cr(VI) and, similarly, resistance against other heavy metal ions such as $Ni^{2+}$ (800 mg/l), $Cu^{2+}$ (600 mg/l), $Pb^{2+}$ (1,100 mg/l), $Cd^{2+}$ (350 mg/l), $ZN^{2+}$ (700 mg/l), and $Fe^{3+}$ (1,000 mg/l), and against selected antibiotics. Cr-B2 was observed to efficiently reduce 200 mg/l Cr(VI) completely in both nutrient and LB media, and could convert Cr(VI) to Cr(III) aerobically. Cr(VI) reduction kinetics followed allosteric enzyme kinetics. The $K_m$ values were found to be 43.11 mg/l for nutrient media and 38.05 mg/l for LB media. $V_{max}$ values of 13.17 mg/l/h and 12.53 mg/l/h were obtained for nutrient media and LB media, respectively, and the cooperativity coefficients (n) were found to be 8.47 and 3.49, respectively, indicating positive cooperativity in both cases. SEM analysis showed the formation of wrinkles and depressions in the cells when exposed to 800 mg/l Cr(VI) concentration. The organism was seen to exhibit pleomorphic behavior. Cr-B2 was identified on the basis of morphological, biochemical, and partial 16S rRNA gene sequencing chracterizations and found to be Acinetobacter sp.

• Resources Recycling
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• v.9 no.6
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• pp.45-52
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• 2000

Generally, the residues of EAF's dusts treated by reduction process at high temperature are disposed. If the residues can be recycled as iron sources of EAF by upgrading their iron contents, it can be expected to reduce the amounts of disposed wastes and the environmental impacts. Reduction of EAF's dusts mixed with millscale was carried out in rotary hearth furnace to upgrade iron contents of reduction residues. Dusts should be reduced rapidly to protect from reoxidation of reduced iron residue which can be reoxidized at high temperature. In our experimental conditions, optimum reduction time was about 40min. and iron contents of the residues were increased with increasing mixing ratio of millscale and upgrade to 85% at 50%wt mixing ratio. Zinc and lead contents in residues were about 3% and 0.5% respectively. The residues reduced rapidly must be recycled in EAF because heavy metal elements in the residues can be extracted easily and contaminate air and water.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.623-633
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• 2017

Food waste has been recognized as a organic sources for composting and many research was conducted to efficiently utilize or treat. This study was to evaluate a feasibility for producing food waste compost under co-composting with mixture of food and animal waste. The mixing ratio of food and animal waste was 35% as main material, which additionally mixed 30% of sawdust for co-composting. Total days of composting experiment were 84 days and each sub samples were collected at every 7 days from starting of composting. Results showed that inner temperature in composting was rapidly increased to $70{\pm}4^{\circ}C$ within 3~5 days depending on mixing animal waste of cattle, pig, and chicken base compared to sole food waste base. Expecially, the CN ratio in the mixture of food and pig water was the highest (16.2) among compost. After finishing composting experiment, maturity was evaluated with solvita and germination test. Maturity index (MI) of the mixture of food and animal waste was ranged between 6~7, but was 3 in sole food waste. Calculated germination index (GI) was at the range of about 100 irrespectively of mixing of food and animal waste. However, NaCl content and heavy metal as Cr, Cu, Ni, Pb, and Zn contents was increased in the mixture of food and animal waste. which was the highest in compost mixed the food and pig waste. Both MI and GI showed that manufactured fertilizer was suitable for fertilizer criteria while sole food waste was not adequate for composting due to composting periods. Overall, mixing the food and animal waste can be utilized for improving compost maturity, but more research should be conducted to make high quality of food waste compost with animal waste in agricultural fields.