• Journal of Environmental Health Sciences
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• v.21 no.2
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• pp.20-26
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• 1995

The objective of this study is to estimate the effect of the bed expansion and the characteristics of attached biomass in the start-up in the anaerobic fluidized bed reactor(AFBR). The fluidized bed reactor was operated with bacteria supported on the bed of granular activated carbon(GAC). The reactor was operated at 35$\circ$C, 5 kg $COD/m^3\cdot day$ at bed expansion varying from 0 to 100% with soluble glucose wastewater(5,000 mg/l). When the effluent reached a steady state at 100% of bed expansion, maximum COD removal efficiency of 87.3% and 0.031 $m^3CH_4/kg COD_{removed}$ were obtained. At higher bed expansion, COD removal efficiency, methane production rate and biogas production rate increased. Especially, at 50% of bed expansion, the efficiency of the treatment increasedg rapidly in the AFBR. The biomass colonized in the pits and crevices of the GAC particle and no complete biofilm was established in the bioreactor during the experiment.

• Journal of Environmental Science International
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• v.7 no.4
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• pp.481-486
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• 1998

This paper discussed about the effect of Zoogloea ramigera on the initial microorganism attachment and the biofilm growth. The additions of 5, 10 and 15%(w/w) of Zoogoea ramigera were facilitated for the initial attachment on the surface of the acryl disk. At biofilm growth, the more Zoogoea ramikera added to the activated sludge, the more biofilm dry weight was obtained. In order to get the stable blofllm and to mlnlmlze the start-up periods, Initial biofilm formation using activated sludge with floe forming microorganisms like Zoogloea ramigera was recommended rather than that without floe forming microorganisms.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.133-134
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• 1997

1. 서론 : 제지산업은 용수 다소비용 산업으로, 생산하는 제품 톤당 약 40톤으로 폐수가 배출되고 있으며 공정내로 재활용하는 폐수량을 고려한다면 그 사용량은 더욱 클 것이다. 이와 같은 다량의 용수 사용으로 인하여 제지 공장의 폐수를 제조공정에서 재활용하는 방법이나 배출량을 감소시키는 방안들이 법률적이나 경제적인 측면에서 연구되고 있는 실정이다. 본 연구에서는 기존의 응집, 침전공정을 대신하고 여재를 이용힌 물리적 여과와 활성높은 미생물이 여재 표면에 부착되어 수중 유기물질을 생물학적으로 분해 제거하는 이중의 효과를 거둘 수 있는 호기성 생물막 공정을 도입하고 그 처리수의 유기물 및 용존 무기물을 Membrane 공정으로 제거함으로써 제지공업폐수를 재활용하여 용수기준까지 처리하 System의 개발을 그 목적으로 하였다.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.3
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• pp.19-25
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• 1994

In this research, characteristics of nitrification and denitrification using the microorganism attached on sponge and plates were examined. The denitrification and nitrification performance were investigated under the anaerobic and aerobic condition for about 2 months. Because the basins of denitrification and nitrification were connected in series, wastewater was flowed from denitrification basin to nitrification one. The 90% of influent flowrate was returned from nitrification basin to denitrification one. Most of organic material was removed in nitrification basin, wherease the only exact amount of organics required in denitrification process was removed in denitrification one. This experiment resulted in that heterotrophic bacteria existing in aerobic basin governed the removal efficiency of organic compounds. In case the influent BOD concentration into nitrification basin was 80mg/l, it did not affect to accumulation of nitrifying bacteria, the balance of heterotrophic bacteria was proved to be an important factor in nitrification/denitrification method such as anaerobic and aerobic cycling type.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.104-109
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• 1998

The objective of this study was to examine the effect of polymer coating on the initial microorganism attachment and the biofilm growth. Such as nonion(polyacrylamine), anion(CMC-Na) and cation polymer coagulant(chitosan and PEI) were used for coating material of the support carrier(acryl plate). When polymer coagulant was coated with 5, 10, 20, 35, 50, 100 and 200 mg/l on the surface of acryl plate, initial microorganism attachment increased and optimum concentration for the attachment was 35 mg/l. Biofilm growth experiments were conducted with the substrate loading of 12.7gSCOD/$m^2\cdot$ day using RBC. The polymer coagulants such as CMC-Na, polyacrylamide, PEI and chitosan coating on the acryl plate facilitated the biofilm growth of microorganisms. Until the biofilm dry weight grows up to 0. 0038g/cm$^2$, biofilm growth on the plate coated with cation polymer like chitosan was better than that on the coated plate of nonion(polyacrylamine), anion(CMC-Na) polymer coagulant.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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• pp.245-246
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• 2005

Acinetobacter sp.가 외부환경보다 많이 발견되었다는 것으로 보아 이 균이 섬유류 유물의 훼손에 영향을 많이 미칠 것으로 보인다 Co교nebacterium sp., Bacillus sp.등은 외부환경이나 전시실 등에서 전혀 발견되지 않았으나 유물보관함에서 발견되었다. 때문에 이 세균들은 외부환경으로부터 유입된 균이 아니라고 추정되며, 이 균들이 섬유류 유물에 어떠한 영향을 미치는지 연구해 볼 필요성이 있다. 섬유의 부착세균으로는 공중 부유에서 대다수로 검출되었던 Acinetobacter spp., Pseudomonas spp., Neisseria spp.,등으로 공기를 통해 섬유류 유물이 오염된다는 것을 확인할 수 있었다.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.138-144
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• 2011

Purpose: The purpose of this study was to evaluate the cleansing effect of recently developed alkaline ionized water, e-WASH, on microorganisms of the denture surface. Materials and methods: Removable partial and complete dentures were randomly assigned to the experimental group of 41 dentures, and the control group of 26. The denture was immersed in the e-WASH solution (experimental group), or tap water (control group) for 5 minutes. The plaque was collected from the denture surface before and after immersion, and smeared on the slide glass. Amount and motility of microorganisms were compared according to the morphology and strain of microorganisms, using the phase contrast microscope. Statistical analysis was accomplished with paired t-test and independent t-test at 95% confidence level (P<.05). Results: 1. The amount of cocci, bacilli, filamentous, spiral/comma, and the motility of bacilli, filamentous, and spiral/comma were decreased after denture cleansing with the alkaline ionized water, e-WASH (P<.05). But in the control group, only the amount of cocci showed a significant difference (P<.05), but no difference from the others. There were no differences in other analysis. 2. In the experimental group, the amount of cocci, bacilli, filamentous, spiral/comma, and the motility of bacilli, filamentous, and spiral/comma were smaller and more inactive compared to the control group (P<.05). Conclusion: These results indicated that the alkaline ionized water, e-WASH could effectively reduce the amount and motility of the experimented microorganisms on the denture surface, and that e-WASH could be recommended as an effective denture cleanser.

• Analytical Science and Technology
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• v.21 no.4
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• pp.338-343
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• 2008

Extraction of DNA from skeletal material is of great importance in the identification of human remains, but is particularly difficult because the high amount of microbial DNA was often co-extracted with human bone DNA. We found that a phenol/chloroform extraction, followed by ultrafiltration, and cleanup by via the $QIAquick^{(R)}$ PCR purification kit yields higher amounts of human genomic DNA compared with extraction by the column affinity $method^{(R)}$ alone. Ultrafiltration extraction of human DNA from ten exhumed bone samples yielded $0.041-1.120ng/{\mu}L$ DNA (mean = $0.498ng/{\mu}L$ DNA), and purification using the column affinity resulted in $0.016-0.064ng/{\mu}L$ DNA (mean = $0.034ng/{\mu}L$ DNA). Although the STR genotyping by the column affinity method was partially successful, all DNA samples by the ultrafiltration method produced full profiles from the multiplex PCR. The efficiency of STR genotyping was in accordance with the amounts of the human DNA extracted.

• Journal of Soil and Groundwater Environment
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• v.14 no.3
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• pp.40-46
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• 2009

The applicability of a well-type autotrophic sulfur-oxidizing reactive barrier (L $\times$ W $\times$ D = $3m\;{\times}\;4\;m\;{\times}\;2\;m$) as a long-term treatment option for nitrate removal in groundwater was evaluated. Pilot-scale (L $\times$ W $\times$ D = $8m\;{\times}\;4\;m\;{\times}\;2\;m$) flow-tank experiments were conducted to examine remedial efficacy of the well-type reactive barrier. A total of 80 kg sulfur granules as an electron donor and Thiobacillus denitrificans as an active bacterial species were prepared. Thiobacillus denitrificans was successfully colonized on the surface of the sulfur granules and the microflora transformed nitrate with removal efficiency of ~12% (0.07 mM) for 11 days, ~24% (1.3 mM) for 18 days, ~45% (2.4 mM) for 32 days, and ~52% (2.8 mM) for 60 days. Sulfur granules attached to Thiobacillus denitrificans were used to construct the well-type reactive barrier comprising three discrete barriers installed at 1-m interval downstream. Average initial nitrate concentrations were 181 mg/L for the first 28 days and 281 mg/L for the next 14 days. For the 181 mg/L (2.9 mM) plume, nitrate concentrations decreased by ~2% (0.06 mM), ~9% (0.27 mM), and ~15% (0.44 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. For the 281 mg/L (4.5 mM) plume, nitrate concentrations decreased by ~1% (0.02 mM), ~6% (0.27 mM), and ~8% (0.37 mM) after $1^{st}$, $2^{nd}$, and $3^{rd}$ barriers, respectively. Nitrate plume was flowed through the flow-tank for 49 days by supplying $1.24\;m^3/d$ of nitrate solution. During nitrate treatment, flow velocity (0.44 m/d), pH (6.7 to 8.3), and DO (0.9~2.8 mg/L) showed little variations. Incomplete destruction of nitrate plume was attributed to the lack of retention time, rarely transverse dispersion, and inhibiting the activity of denitrification enzymes caused by relatively high DO concentrations. For field applications, it should be considered increments of retention time, modification of well placements, and intrinsic DO concentration.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.108-113
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• 2014

Pseudomonas aeruginosa and Vibrio vulnificus are Gram-negative human pathogens, which exert their virulence through quorum sensing (QS) regulation. The infection of these pathogens have been known to be mediated by biofilm formation in many cases and this study carried out the time-course analysis of biofilm formation depending on the QS regulation in P. aeruginosa and V. vulnificus. In P. aeruginosa, our results demonstrated that QS-deficient mutant better attached to surface at initial stage of biofilm formation, but poorly proceeded to the maturation of the biofilm structure, while wild type less attached at initial stage but developed highly structured biofilm at late stage. Because of this, the quantitative comparison of biofilm formation between wild type and the QS mutant showed the reversion; the QS mutant formed more biofilm until 10 h after inoculation than wild type, but wild type formed much more biofilm after 10 h than QS mutant. V. vulnificus has been reported to form more biofilm with the mutation on QS system. When we performed the same time-course analysis of the V. vulnificus biofilm formation, the reversion was not detected even with prolonged culture for 108 h and the QS mutant always forms more biofilm than wild type. These results indicate that the QS regulation negatively affects the attachment at early stage but positively facilitates the biofilm maturation at late stage in P. aeruginosa, while the QS regulation has a negative effect on the biofilm formation throughout the biofilm development in V. vulnificus. Based on our results, we suggest that the developmental stage of biofilm and bacterial species should be considered when the QS system is targeted for biofilm control.