• The Journal of Natural Sciences
• /
• v.12 no.1
• /
• pp.61-67
• /
• 2002

The results of laboratory experiments with microcosms containing Daphnia magna and Chlorella vulgaris demonstrated decrease of the structural exergy of artificial communities after the addition of model toxicants phenol and cobalt chloride. Structural exergy changes were more expressed than changes of components biomasses and total biomass of the community. It once more points to the possibility of the use structural exergy as ecosystem health reflecting parameter.

• The Korean Journal of Ecology
• /
• v.25 no.3 s.107
• /
• pp.139-144
• /
• 2002

Most of army depots contaminated with co-contaminants, 2,4,6-trinitrotoluene(TNT) and heavy metals. In phytoremediation for the TNT, heavy metals may inhibit mineralization, transformation and sequestration of TNT by the plant. We studied effect of cadmium on TNT degradation and transformation by Abutilion avicennae in hydroponic cultures. When cultured in 20 mgTNT/L and 1.3 mgCd/L, the plant displayed phytotoxicities; reduction of leaf fresh, leaf roil, chlorosis, leaf loss and fresh weight loss. Phytotoxicity was severer in the combined contaminants than in single contaminant. Because A. avicennae uptake just a little cadmium, 1.3 mgCd/L included in the TNT medium did not influece significantly TNT transformation, translocation and distribution by A. avicennae. Therefore, the soil solution containing cadmium would not affect TNT degradation by Abutilion avicennae in Army depots polluted with TNT.

• The Korean Journal of Ecology
• /
• v.25 no.2
• /
• pp.69-74
• /
• 2002

Most of army depots contaminated with co-contaminants. 2,4,6-trinitrotoluene(TNT) and heavy metais. In phytormediation for the TNT, heavy metals may inhibit mineralization, transformation and sequestration of TNT by the plant. W studied effect of cadmium on TNT degradation and transformation by Abutilion avicenneae in hydroponic cultures. When cultured in 20 ㎎TNT/L and 1.3 ㎎Cd/L. the plant displayed phytotoxicities; reduction of leaf fresh, leaf roll, chlorosis, leaf loss and fresh weight loss. Phytotoxicity was severer in the combined contaminnts than in single contaminant. Because A. avicennae uptake just a little cadmium, 1.3 ㎎Cd/L induded in the TNT medium did not influece significanfly TNT transformation, translocation and distrivution by A. Therefore, the soil solution containing cadmium would not affect TNT degradation by Abutilion avicennae in Amy depots polluted with TNT.

• Membrane Journal
• /
• v.24 no.3
• /
• pp.249-257
• /
• 2014

This experiment was carried out for a laboratory scale activated sludge bioreactor equipped with submerged flat sheet membrane using the synthetic wastewater. The membrane system for the activated sludge solution of MLSS 5,000 mg/L was operated with constant permeate flux by continuously permeating and periodically 10 minute-permeating/2 minute-resting modes, respectively. The transmembrane pressure was measured as the permeate flux increased from 10 to $25L/m^2{\cdot}hr$ under the constant air flowrate 0.25 L/min. Also, the complete blocking, standard blocking, intermediate blocking, incompressible cake and linear compressible cake fouling models were retrofitted for the experimental data in order to determine the state of the membrane fouling. Because the transmembrane pressure fluctuated as a pulse shape for every period of 10 minute-permeating/2-minute resting mode, the membrane fouling models were separately applied for the maximum and minimum connecting lines. The linear compressible cake fouling model for the activated sludge cakes was the best fitted with the experimental results from the above five models.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.3
• /
• pp.66-77
• /
• 2006

This review inquired the recently applied molecular biological and biochemical methods analyzing the microbial community structure of groundwater and, as a result, summarized the functional or taxonomic groups of active microorganisms with major contaminants in groundwater. The development of gene amplification through PCR has been possible to figure out microbial population and identification. Active microbial community structures have been analyzed using a variety of fingerprinting techniques such as DGGE, SSCP, RISA, and microarray and fatty acid analyses such as PLFA and FAME, and the activity of a specific strain has been examined using FISH. Also, this review included the dominant microflora in groundwater contaminated with fuel components such as n-alkanes, BTEX, MTBE, and ethanol and chlorinated compounds such as TCE, PCE, PCB, CE, carbon tetrachloride, and chlorobenzene.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.795-798
• /
• 2008

An estuary is very important that the seawater and the freshwater meet and they formed wide foreshore and estuarine which is used as the habitat of various living thing and spawning bed of fish. Masan bay is typical closing bay in Korea. It is located 9 km from the open sea and most inside of Jinhae bay. The width of bay entrance is less than 1 km, where the flow velocity is very low. The large scale industrial complex of Masan bay is located in near Masan and Changwon city whose population is about 100 million. Because of low tidal velocity, the pollutants from the land are accumulated, which makes the water quality worse in Masan bay. The purpose of this study is to analyze the various hydraulic characteristics using RMA-2 model. The advection and diffusion of pollutant is also simulated using RMA-4 model according to the inflow of Changwon-stream and Nam-stream. The hydraulic simulations include the effect of tide which can be characterized by the tide data of Masan bay tide observatory.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.414-424
• /
• 2009

The research was to get a biological assessment on Bokha stream and Dal stream, using the physicochemical factors and the epilithic diatom from June, 2008 to March, 2009. As a result, Bokha stream showed high consistency of total phosphorus ($0.041{\sim}0.886\;mg{\cdot}L^{-1}$), and total nitrogen ($0.336{\sim}10.532\;mg{\cdot}L^{-1}$). Also, the concentration of BOD showed most of the sites polluted as $2{\sim}5\;mg\cdot}L^{-1}$ except for the upstream sites. However, excluding downstream sites and other few sites, Dal stream had very clean water quality having total phosphorus less than $0.06\;mg\cdot}L^{-1}$, and total nitrogen less than $2.0\;mg\cdot}L^{-1}$. Out of the 12 total sites, 98 taxa of epilithic diatoms appeared: 67 taxa from Bokha stream, and 78 taxa from Dal stream. The results of the water quality assessment showed that, Bokha stream, having TDI level over 80, was mostly $\alpha$-mesosaprobic, which indicates a severe pollution. On the other hand, Dal stream, having TDI level below 50, was examined to be xenosaprobic and $\alpha$-oligosaprobic, which indicates a clean water quality. The correlation between DAIpo and TDI measured to be high in correlation coefficent (0.83) from the result of correlation analysis. When the water quality is good, there is an inclination of getting high correlation between chemical and biological water quality assessment results. TDI, which uses numerous taxa of diatoms, showed more stability than DAIpo, which uses less amount of taxa of diatoms to get its result.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1996.10a
• /
• pp.60-61
• /
• 1996

염색폐수를 처리하기 위하여, 일반적으로 물리.화학적 공정과 호기성 생물학적 공정을 조합한 방법들을 사용하고 있다. 하지만 호기성 생물학적 공정은 난분해성 물질의 제거능력이 낮고, 염색폐수의 주된 오염원인 염료분자가 호기성 미생물에 대한 에너지원으로 적합하지 않아 분해되기 어려우며, 물리.화학적 공정을 이용한 처리방법으로도 높은 처리효율을 얻을 수가 없다. 이러한 문제점을 극복하기 위하여 염색폐수 처리에 혐기-호기공정을 이용하며, 혐기성 공정에서 생물학적으로 분해되기 어려운 고분자 물질들을 가수분해하여 생물학적으로 분해가능한 저분자물질로 전환시키고, 호기성 공정에서 저분자 물질을 효과적으로 처라할 수 있기때문에 기존의 염색폐수 처리공정에 비하여 훨씬 높은 처리효율을 얻을 수 있다. 특히, 혐기성 미생물은 호기성 미생물에 비하여 난분해성 물질에 대한 분해력이 높고, 생물독성 물질에 대한 내성이 강하기 때문에 수중생물에 유해한 염료를 함유한 염색폐수의 색도제거에 효과적인 것으로 기대된다. 또한, 막분리 공정은 유기물 및 미생물이 막표면에 축적, 증식함으로써 막세공에 막힘현상을 초래하여 역세척 등의 물리적인 방법이나 화학약품을 이용한 화학적 세척 방법으로도 투과플럭스의 회복이 불가능한 상태를 유발함으로 막의 수명을 단축시키는 원인이 된다. 따라서, 혐기-호기공정과 조합하면 색도성분 제거 및 막 오염의 원인이 되는 유기물 및 용존성 고형물을 제거하고, 막 오염의 억제를 통한 후 수염의 연장은 물론, 처리수의 수질향상에 활용될 수 있을 것으로 사료된다.1로 강구와 함께 공구강 vial에 장입 후, Spex mixer/mill을 이용하여 기계적 합금화 하였다. 기계적 합금화 공정으로 제조한 분말에 대한 X-선 회절분석과 시차 열분석으로 합금화 정도를 분석하였다. (Bi1-xSbx)2Te3 및 Bi2(Te1-ySey)3 합금분말을 10-5 torr의 진공중에서 300℃∼550℃의 온도로 30분간 가압소결하였다. 가압소결체의 파단면에서의 미세구조를 주사전자현미경으로 관찰하였으며, 상온에서 가압소결체의 열전특성을 측정하였다. (Bi1-xSbx)2Te3의 기계적 합금화에 요구되는 공정시간은 Sb2Te3 함량에 따라 증가하여 x=0.5 조성에서는 4 시간 45분, x=0.75 조성에서는 5 시간, x=1 조성에서는 6 시간 45분의 vibro 밀링이 요구되었다. n형 Bi2(Te1-ySey)3 합금분말의 제조에 요구되는 밀링시간 역시 Bi2Se3 함량 증가에 따라 증가하였으며 Bi2(Te0.95Se0.05)3 합금분말의 제조에는 2시간, Bi2(Te0.9Se0.1)3 및 Bi2(Te0.85Se0.15)3 합금분말의 형성에는 3시간의 bivro 밀링이 요구되었다. 기계적 합금화로 제조한 p형 (Bi0.2Sb0.8)2Te3 및 n형 Bi2(Te0.9Se0.1)3 가압 소결체는 각기 2.9x10-3/K 및 2.1x10-3/K 의 우수한 성능지수를 나타내었다.ering)가 필수적이다. 그러나 침전법에서 얻게 되는 분말은 매우 미세하여 colloid를 형성하게 되며, 이러한 colloid 상태의 미세한 침전입자가 filte

• Korean Journal of Environmental Biology
• /
• v.25 no.3
• /
• pp.191-196
• /
• 2007

Indoor air differs from outdoor atmosphere since it contains chemical and physical contaminants from building materials. This study deals with the biological effects of volatile organic compounds (VOCs) released from synthetic fiber carpet materials. One group of Tradescantia inflorescence was exposed to VOCs from the carpet sample in the environmental test chamber, while the other inflorescence group was exposed to a TO-14 standard gas mixture (1 ppm) for comparison. After the exposure, VOCs from the carpet were analysed by the desorber/GC/MS method, and micronuclei in the pollen mother cells of Tradescantia were scored under a microscope $({\times}400)$ to evaluate the genotocixicity induced by the exposure to VOCs. The chemical analysis confirmed that a total of 12 VOCs were released from the carpet materials, among which stylene $(71.9{\mu}g\;m^{-3})$ and toluene $(49.6{\mu}g\;m^{-3})$ were in the highest concentration. Twenty four hours of exposure to VOCs from the carpet in the environmental test chamber resulted in a micronucleus frequency as high as $7.73{\pm}0.75MCN$ per 100 tetrads, which was similar to that induced after exposure to the TO-14 standard gas mixture (1 ppm) for 4 hours. Meanwhile, two hours of exposure to the standard gas mixture did not cause a significant increase in the genotoxicity compared to the spontaneous micronucleus frequency. This result indicates that exposure for a long time to the air contaminated with VOCs from the carpet materials causes a genotoxic effect. The biological-chemical combination analyses in the study proved to be an effective tool for monitoring the indoor air contaminants.

• Economic and Environmental Geology
• /
• v.42 no.5
• /
• pp.427-434
• /
• 2009

Indigenous bacterium which shows a tolerance to high metal toxicity was isolated from soil concomitantly contaminated with oil and heavy metals. The characteristics of the bacterium for Pb and Cd biosorption was investigated under the various experimental conditions such as bacterial growth phase, the initial metal concentration, the input biomass amount, temperature and pH. The Langmuir adsorption isotherm modeling was described to know the capacity and intensity of biosorption. The low initial concentration of heavy metals and high biomass has a maximum heavy metal removal efficiency, but biosorption capacity of Pb and Cd has different values. Biosorption efficiency was highest in the end of the microbial growth stage and under pH 5~9 condition, but was less affected by temperature variation of 25~$35^{\circ}C$. The maximum biosorption capacity for Pb and Cd was 62.11 and 192.31 mg/g, respectively and each $R^2$ was calculated as 0.71 and 0.98 by applying Langmuir isothermal adsorption equation. Biosorption for Cd was considered as monomolecular adsorption to single layer on the surface of cells, whereas biosorption for Pb was considered as accumulation process into the cell by the microbial metabolism and precipitation reaction with anion of bacteria.