• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1434-1443
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• 2019

Although chemical oxygen demand (COD) is an important issue for wastewater treatment, COD reduction with microalgae has been less studied compared to nitrogen or phosphorus removal. COD removal is not efficient in conventional wastewater treatment using microalgae, because the algae release organic compounds, thereby finally increasing the COD level. This study focused on enhancing COD removal and meeting the effluent standard for discharge by optimizing sludge inoculation timing, which was an important factor in forming a desirable algae/bacteria consortium for more efficient COD removal and higher biomass productivity. Activated sludge has been added to reduce COD in many studies, but its inoculation was done at the start of cultivation. However, when the sludge was added after 3 days of cultivation, at which point the COD concentration started to increase again, the algal growth and biomass productivity were higher than those of the initial sludge inoculation and control (without sludge). Algal and bacterial cell numbers measured by qPCR were also higher with sludge inoculation at 3 days later. In a semi-continuous cultivation system, a hydraulic retention time of 5 days with sludge inoculation resulted in the highest biomass productivity and N/P removal. This study achieved a further improved COD removal than the conventional microalgal wastewater treatment, by introducing bacteria in activated sludge at optimized timing.

• Environmental Engineering Research
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• 제19권3호
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• pp.283-287
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• 2014

Cultivation of microalgae using wastewater exhibits several advantages such as nutrient removal and the production of high valuable products such as lipid and pigments. With this study, two types of wastewater from instant noodle factory; mixed liquor suspended solids (MLSS) and effluents after sedimentation tank were investigated for green microalga Scenedesmus sp. cultivation under laboratory condition. Optimal wastewater dilution percentage was evaluated in 24 wells microplate. MLSS and effluent without dilution showed the highest specific growth rate (${\mu}$) of $1.63{\pm}0.11day^{-1}$ and $1.57{\pm}0.16day^{-1}$, respectively, in which they were significantly (p < 0.05) higher than Scenedesmus sp. grown in BG11 medium ($1.08{\pm}0.14day^{-1}$). Ten days experiment was also conducted using 2000 ml Duran bottle as culture vessel under continuous light at approximately 5000 lux intensity and continuous aeration. It was found that maximum biomass density of microalgae cultivated in MLSS and effluent were $344.16{\pm}105.60mg/L$ and $512.89{\pm}86.93mg/L$ respectively and there was no significant (p < 0.05) difference on growth to control (BG11 medium). Moreover, cultivation microalgae in wastewater could reduce COD in wastewater by 39.89%-73.37%. Therefore, cultivation of Scenedesmus sp. in wastewater from instant noodle factory can yield microalgae biomass production and wastewater reclamation using photobioreactor simultaneously.

• 환경위생공학
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• 제11권2호
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• pp.53-58
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• 1996

This study was performed to measure and evaluate the characteristics of removal efficiency and kinetics in the electrolytic decolorizing process of dye wastewater containing acid dye Red 114 by using Fe anode. The synthetic wastewater samples of 500, 1000, $2000mg/{\ell}$ concentration were tested and as an attempt to assess the feasibility of the present system for the industrial application, a sample of wastewater collected by J textile factory in Eujungbu city was also treated. It was found that the optimum conditions were pH 7, 8Volt and removal efficiency in synthetic wastewater containing $2000mg/{\ell}$ of dye and 0.2% of electrolyte (NaCl) was 99.68% after 20minutes of reaction time. In this condition, overall rate constant was $4.77{\times}10^{-5}mmol/cm^{3}hr$. The Decolorizing efficiency and COD removal efficiency of J textile factory wastewater were 99% and 86% respectively at pH 7, 8Volt for 40minutes of reaction time.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.342-343
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• 2009

Paper factories use a large amount of water and same amount of wastewater is generated. It is important to purity and recycle the wastewater because of water shortages and water pollution. The existing water treatment facilities like precipitation process need large-scale equipment and wide space to purity the wastewater of paper factory. High gradient magnetic separation (HGMS) system has the merits to purity rapidly because of large voids at filter and to occupy small space. In this paper, two types of superconducting magnets were used for HGMS systems. Cryo-cooled Bi-2223 superconducting magnet system with 70 mm room temperature bore and 200 mm of height was prepared. Cryo-cooled Nb-Ti superconducting magnet with 100 mm room temperature bore and 600 mm of height was used for magnetic separator. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. The effects of magnetic separation of wastewater were investigated as variation of magnetic field strength and flow rate of wastewater.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.4-4
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• 2009

Paper factories use a large amount of water and same amount of wastewater is generated. It is important to recycle the wastewater because of water shortages and water pollution. The existing water treatment facilities like precipitation process need large-scale equipment and wide space to purify the wastewater of paper factory. High gradient magnetic separation (HGMS) system has the merits to purify rapidly because of large voids at filter and to occupy small space. In this paper, two types of superconducting magnets were used for HGMS systems. Cryo-cooled Bi-2223 superconducting magnet system with 70 mm room temperature bore and 200 mm of height was prepared. Cryo-cooled Nb-Ti superconducting magnet with 100 mm room temperature bore and 600 mm of height was used for magnetic separator. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. The effects of magnetic separation of wastewater were investigated as variation of magnetic field strength and flow rate of wastewater.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2009년도 Korea Superconductivity Society Meeting 2009
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• pp.122-122
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• 2009

• 한국균학회지
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• 제21권2호
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• pp.127-132
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• 1993

269 yeast strains were isolated from water samples collected from different sites in Minia governorate. These included 126 strains from fresh water, 108 strains from sewage and 35 strains from wastewater from sugar-cane factory. On the basis of 23 different physiological and morphological merkmals, the isolated strains were assigned to 16 species belonging to 11 genera. Total yeast cell counts as well as spectra of yeast species were highly variable in tested water. Total yeast cell counts ranged between $3.0{\times}10^3/l\;and\;1.8{\times}10^6/l$ for fresh water, $3.0{\times}10^4/l\;and\;3.0{\times}10^7/l$ for sewage and $1.5{\times}10^6/l\;and\;2.6{\times}10^7/l$ for wastewater from sugarcane factory. Debaryomyces hansenii, Rhodotorula mucilaginosa and Torulaspora delbrueckii were the dominant species in fresh water, whereas Debaryomyces hansenii, Thrichosporon beigelii, Rhodoforula mucilaginosa and Kluyveromyces marxianus were the dominant species in sewage and Saccharomyces cerevisiae, Kluyveromyces marxianus and Trichosporon beigelii were the dominant species in wastewater from sugar-cane factory. Yeast human pathogens, Trichosporon beigelii, Rhodotorula mucilaginosa and Candida albicans were encountered in water samples indicating that water in El-Minia governorate is also polluted by some pathogenic yeasts.

• 한국융합학회논문지
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• 제11권10호
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• pp.213-217
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• 2020

천연 광물질, 식물질, 정수장 슬러지를 이용하여 친환경적인 수수질정화제와 이를 활용하는 오폐수복합처리시스템을 개발하였다. 오폐수복합처리시스템은 오염수 유입, 수질정화제 투입, 가압부상장치 가동, 슬러지 부상, 슬러지 수거 및 처리수 배출의 과정을 거친다. 이 장치를 축분 탈리액, 육계 세척수, 공장 폐수, 하수종말처리장 및 연못의 녹조제거에 적용하여 우수한 제거율을 얻었다. 유기성 폐기물 정화에 천연 수질정화제를 활용한 예는 조사되지 못했다.

• 한국물환경학회지
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• 제22권5호
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• pp.913-918
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• 2006

Both raw wastewater and effluent from a rubber products manufacturing factory were found to be toxic to Daphnia magna though the effluent satisfied current water quality standards. Thus, in order to reduce toxicity, advanced oxidation processes (AOPs) such as gamma-ray (${\gamma}-ray$) treatment and ozonation ($O_3$) were applied. A combined ${\gamma}-rays/O_3$ treatment at 20 kGy after coagulation significantly reduced toxicity of raw wastewater, changing 48-h toxic unit (TU) value from 201.21 to 23.92. However, toxicity of treated water was higher than that of effluent (TU = 12.15). This shows limitation of gamma-ray treatment to remove toxicity of raw wastewater. In case of effluent, the combined ${\gamma}-rays/O_3$ treatment at 20 kGy efficiently decomposed toxic compounds down to non toxic level. This work strongly supports the necessity of toxicity reduction evaluation as well as toxicity-based effluent management.

• 한국지반공학회논문집
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• 제24권4호
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• pp.5-13
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• 2008

연약한 실트지반(ML)과 생활오폐수와 공장폐유로 오염된 실트지반($ML_p$)에 실내모형실험을 실시하여 오염물질의 증가에 따른 지지력값의 변화 등에 대한 실제의 적용성을 기존의 연구결과와 비교 분석하였다. 생활오폐수와 공장폐유로 오염된 실트지반은 오염물질 함량이 점차 증대할수록 오염물질의 영향으로 연약한 실트지반 보다 지반의 소성화가 촉진되어 지반의 강도특성은 감소하는 것으로 나타났다. 연약한 실트지반의 한계하중 값 $q_{cr}=4.14c_u$, 극한지지력 값 $q_{ult}=9.53c_u$로 산정되었으며, 생활오폐수와 공장폐유로 오염된 실트지반의 한계하중 값 qcr=1.78cu, 극한지지력 값 $q_{ult}=4.39c_u$로 산정되었다. 생활오폐수와 공장폐유로 오염된 실트지반의 한계하중과 극한지지력 값이 연약한 실트지반의 한계하중과 극한지지력 보다 다소 작게 나타났다. 이는 오염물질의 증가로 인하여 전단저항이 저하되므로써 다소 작은 값을 나타낸 것으로 사료된다.