• Title/Summary/Keyword: 저농도 유기물

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Mechanism of Oxygen-Deficient Water Formation in Jindong Bay (진동만의 빈산소수괴 형성기구)

  • 김동선;김상우
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.8 no.2
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    • pp.177-186
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    • 2003
  • The influences of horizontal and vertical flow components including the stratification of water column and the wind field on the formation of oxygen-deficient water in summer in Jindong Bay, northern part of Chinhae Bay, were examined. Temperature, salinity and dissolved oxygen in seawater, and direction and velocity of wind were observed in Jindong Bay from March 1998 to February 1999. Low concentration of 5 mg/L in dissolved oxygen (DO) appeared at the bottom layer from May to September. Extremely low DO concentration less than 3 mg/L was investigated in summer (July to August) when stratification was strongest due to abrupt vertical gradients of temperature and salinity in water column. Bottom waters with the extremely low DO concentration were observed even in spring (May to June) at the inner part of the bay. In summer (August to September), the bottom waters with the low DO concentration (less than 5 mg/L) existed at the water depth from 4 to 6 m, being moved upward to the surface layer compared to other seasons. Vertical components of residual flow, calculated by the direction and velocity of wind, in Jindong Bay in summer showed that locally prevailed northerly and westerly wind resulted in downwelling flow at the outer part of the bay and conversely, upwelling at the inner part of the bay. In addition, bottom current at the outer part corresponding to the downwelling area directed to the inner part, probably resulting in a transport of the particulate organic matter settled at the bottom waters to the inner part of the bay. The oxygen-deficient watermass, which was formed at the bottom layer of the inner part, was likely to transported to the surface layer by the upwelling flow.

Characteristics of Stabilization of Excavated Solid Wastes by Aerobic and Anaerobic Landfilling (호기 및 혐기매립에 의한 굴착폐기물의 안정화 특성 연구)

  • Park, Jin-Kyu;Oh, Dong Ik;Lee, Nam-Hoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.12 no.3
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    • pp.76-85
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    • 2004
  • Anaerobic decomposition of municipal solid waste (MSW) had potential adverse impacts such as the production of methane and long-term post closure on human health and the environment. It was demonstrated that aerobic degradation of MSW resulted in the reduction of a methane yield and the enhancement of stabilization of MSW. Excavated solid wastes were both aerobically and anaerobically treated in order to evaluate the effects of air injection on the stabilization of landfill site. The municipal solid waste (MSW) samples were excavated from a 10-year old landfill (operation period: 1991. 11~1994. 11), Jeonju, Korea. Excavated municipal solid wastes are primarily composed of soils and vinyl/plastics. For the two aerobic simulated lysimeters, the levels of $O_2$ ranged 1.6~23.1% and the levels of $CO_2$ ranged 1.5~15.1%, which confirmed the aerobic decomposition. Aeration did prevent methane formation. For the anaerobic simulated lysimeter, the $CO_2$ rose as $O_2$ was consumed and low levels of CH4 were produced. The pH levels ranged from 7.7 to 8.9 for anaerobic lysimeter and from 7.3 to 8.5 for aerobic lysimeters. As expected, aerobic treatment proved to enhance the removal of biodegradable materials in the excavated solid wastes when monitoring the concentration of BOD, COD, $NH_4-N$, and $NO_3-N$ in the leachate.

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Comparative Study on the Inactivation of Oxyfluorfen Mixture with Paraquat or Glyphosate in Soil (Oxyfluorfen을 주재로 한 Paraquat 및 Glyphosate 혼합모형(混合模型) 제초제(除草劑)의 토양중(土壤中) 불활성화(不活性化)에 관한 연구(硏究))

  • Guh, J.O.;Cho, Y.W.
    • Korean Journal of Weed Science
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    • v.6 no.1
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    • pp.76-84
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    • 1986
  • All combinations of oxyfluorfen in 5 dosages and glyphosate in 4 dosages were used to assess the onto-drifting pattern of herbicide inactivation in three different type, such as check soil ($O^-M^-$), organic soil ($O^+M^-$), and micro-organism soil ($O^+M^+$). The plant used for bioassay was rape-hybrid. From the results, it was recognized that the herbicide inactivation is strongly achieved in order of $O^+M^+$ > $O^+M^-$ > $O^-M^-$ soil. Also, the inactivation of oxyfluorfen in soil tended to depend rather on soil microorganisms than organic matter, and to be promoted earlier by paraquat mixture than by that of glyphosate. Average 50 and 95% inactivated time (in days) of herbicides were getting shorten in order of $O^+M^+$, $O^+M^-$, $O^-M^-$, rather prolonged in mixture than in oxyfluorfen single treatment, and rather prolonged in high dose than in low dose, respectively.

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Degradation of Microcystin-LR, Taste and Odor, and Natural Organic Matter by UV-LED Based Advanced Oxidation Processes in Synthetic and Natural Water Source (UV-LED기반 고도산화공정을 이용한 수중 마이크로시스틴-LR, 이취미 물질, 자연유기물 분해)

  • Yang, Boram;Park, Jeong-Ann;Nam, Hye-Lim;Jung, Sung-Mok;Choi, Jae-Woo;Park, Hee-Deung;Lee, Sang-Hyup
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.5
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    • pp.246-254
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    • 2017
  • Microcystin-LR (MC-LR) is one of most abundant microcystins, and is derived from blue-green algae bloom. Advanced oxidation processes (AOPs) are effective process when high concentrations of MC-LR are released into a drinking water treatment system from surface water. In particular, UV-based AOPs such as UV, $UV/H_2O_2$, $UV/O_3$ and $UV/TiO_2$ have been studied for the removal of MC-LR. In this study, UV-LED was applied for the degradation of MC-LR because UV lamps have demonstrated some weaknesses, such as frequent replacements; that generate mercury waste and high heat loss. Degradation efficiencies of the MC-LR (initial conc. = $100{\mu}g/L$) were 30% and 95.9% using LED-L (280 nm, $0.024mW/cm^2$) and LED-H (280 nm, $2.18mW/cm^2$), respectively. Aromatic compounds of natural organic matter changed to aliphatic compounds under the LED-H irradiation by LC-OCD analysis. For application to raw water, the Nak-dong River was sampled during summer when blue-green algae were heavy bloom in 2016. The concentration of extracellular and total MC-LR, geosmin and 2-MIB slightly decreased by increasing the LED-L irradiation; however, the removal of MC-LR by UV-LED (${\lambda}=280nm$) was insufficient. Thus, advanced UV-LED technology or the addition of oxidants with UV-LED is required to obtain better degradation efficiency of MC-LR.

A Study on Quantitation of Polychlorinated Biphenyls (PCBs) in Sediments (저니토중 Polychlorinated Biphenyls(PCBs) 정량에 관한 연구)

  • Shin, Ho-Sang;Oh-Shin, Yunsuk
    • Analytical Science and Technology
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    • v.12 no.2
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    • pp.151-158
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    • 1999
  • This study was conducted to measure the residual PCBs in sediments of 4 great rivers in Korea by gas chromatography-mass spectrometry. From the results, PCBs were positively detected in all samples. The residue levels of total PCBs in sediments in near of SS and OS were $290.87{\mu}g/kg$ and $221.11{\mu}g/kg$, respectively. The PCBs contamination may be in association with total organic compound (TOC) in sediments. Congener 66, 74, 90, 101, 105, 110, 118, 138, 149, 153, 180, 187 as IUPAC No were predominant species found in sediments and the polyCBs detected most aboundantly in sediments were tetraCBs and pentaCBs. From the study, it appears that the PCBs contamination in sediments of 4 great rivers is not serious and the analysis from enough many sites is needed for the next survey.

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A Study on Chemical Speciations and Leaching Potential of Heavy Metals in Polluted Wastes Soils

  • Kim Hee-Joung;Yang Jae-E;Park Byung-Kil;Kong Sung-Ho;Lee Jai-Young;Jun Sang-Ho
    • 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.

A optimization study on the preparation and coating conditions on honeycomb type of Pd/TiO2 catalysts to secure hydrogen utilization process safety (수소 활용공정 안전성 확보를 위한 Pd/TiO2 수소 상온산화 촉매의 제조 및 허니컴 구조의 코팅 조건 최적화 연구)

  • Jang, Young hee;Lee, Sang Moon;Kim, Sung Su
    • Journal of the Korea Organic Resources Recycling Association
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    • v.29 no.4
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    • pp.47-54
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    • 2021
  • In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO2 catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H2-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

Histopathological changes in fish gills by potassium permanganate and influence of water quality (과망간산칼리에 의한 어류 아가미의 병리조직학적 변화와 수질에 따른 영향)

  • Shin, Mee-Young;Choi, Dong-Lim;Chung, Joon-Ki;Chun, Seh-Kyu
    • Journal of fish pathology
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    • v.6 no.1
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    • pp.21-55
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    • 1993
  • Histopathological changes in gills by potassium permanganate were investigated in four fish species. flounder(Pararychthys olivaceus) and rockfish(Sebastes schlegeli) in marine fish, and carp(Cyprinus carpio) and eel(Anguilla japonica) in freshwater fish. Marine fishies were more sensitive to $KMnO_4$ than freshwater fishies and have shown histological changes even in low concentration of 1ppm. Eels were less affected than carp in high concentration of $KMnO_4$. Especially in eels, hyperplasia and hypertropy of mucus cells were observed. Compared to in underground water. the effect of KMnO₄ were reduced very much in pond water. That this differences were due to the concentration of organic substances were certained by experiment with various feed concentrations. The potency of $KMnO_4$ were influenced by dissolved oxygen.

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The Removal and Adsorption Characteristics of 2-MIB & Geosmin using PAC (PAC를 이용한 2-MIB와 Geosmin의 흡착특성과 제거에 관한 연구)

  • Jun, Dae-Young;Lee, Hyeon-Ju;Hong, Seongho;Yoon, Jeyong
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.11
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    • pp.2097-2104
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    • 2000
  • Naturally occurring taste and odor problems include those produced by microorganism. notably algae and bacteria. The major compounds causing taste and odor are MIB and Geosmin which can cause earthy-musty at very low concentration 9ng/L and 4ng/L, respectively. Especially, the problem is very serious from summer to fall in source and finished water. It is well known that using PAC is one of the best technology to control these compounds in drinking water treatment. In this study, optimum dosage and dosing time of PAC were observed with the adsorption isotherm experiments in single and binary compounds. Also, the effect of natural organic matter(NOM) was investigated by using a natural water with JSW. The adsorption capacity of Geosmin was higher than MIB in both with NOM and without NOM. The adsorption capacity of Geosmin and MIB was 4 times lower with NOM than that of without NOM. which was caused by competition adsorption. When the initial concentration of Geosmin and MIB were 100ng/L in JSW, at least 4 hours of reaction time was needed to achieve 99% removal with 20mg/L of the PAC.

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Analysis of Bacterial Community Structure Using FISH in the Juam Reservoir (FISH법으로 분석한 주암호의 세균군집구조)

  • Park, Ji-Eun;Yeo, Sang-Min;Lee, Young-Ok
    • Korean Journal of Ecology and Environment
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    • v.39 no.2 s.116
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    • pp.219-225
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    • 2006
  • Bacterial community structure in the Juam Reservoir was analysed using fluorescent in situ hybridization (FISH) technique from April 2005 to January 2006. Total bacterial numbers varied in the range of 1.58 ${\sim}\;2.73{\times}\;10^6\;cells\;mL^{-1}$ proportional to the concentration of chi-a and had the minimal value in January. The ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria and Cytophaga-Flavobacterium (CF) group to total bacteria ranged from 45.1% to 77.5%, and the ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclasses to total bacteria in June and September with the concentration of chi-a measured were lower than those ratios in April and January. It suggests that enriched growth of Microcystis aeruginosa may inhibit the metabolic activlty of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria. However, the ratio of CF group bacteria represented no large change depending on algal bloom. In terms of nitrifying bacteria, the numbers of ammonia-oxidizing bacteria ranged from 9.9 ${\times}\;10^4\;to\;25.5\;{\times}10^4\;cells\;mL^{-1}$ with sharp fluctuation whereas those of nitrite-oxidizing bacteria varied in 8.7${\sim}9.8{\times}10^4\;cells\;mL^{-1}$ without noticeable change except the maximal value of $20.3{\times}10^4\;cells\;mL^{-1}$ in January maybe due to the high DO.