• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.135-141
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• 1989

Blast furnace slag presents coarse surface for microbes to grow on and high calcium and magnesium contents to neutralize acid to be produced during anaerobic digestion. Also, slag contains aluminum and iron oxides which would promote biological flocculation, and minerals which would stimulate microbial growth. Acid wastes like dairy waste, carbohydrate waste, sanitary landfill leachate and molases wastes were applied without neutralization to laboratory reactors to examine the applicability of blast furnace slag as media. The study results indicated slag media was effective to neutralize pH and maintain microbial population in the system. Particularly, COD removal efficiency was greater than those from plastic media operations treating dairy waste at higher loading rates.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.125-139
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• 2016

Biofilms are considered a complexly structured community of microorganisms derived from their attached growth to abiotic and biotic surfaces. In human life, they mediate serious infections and cause many problems in civil and industrial facilities. While it is of huge interest for scientists to understand biofilms, it has been very hard to directly analyze the various biofilms in nature. A variety of biofilm models have been suggested for laboratory-scale biofilm formation and many methods based on these models are widely used for the biofilm researches. These biofilm models mimic characteristics of environmental biofilms with different advantages and disadvantages. In this review, we will introduce these currently used biofilm model systems and explain their relative merits.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.953-956
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• 2010

본 연구에서는 건축자재로 널리 사용되는 PVC바닥상재 표면에 내오염성과 항균성을 증가시키기 위한 광경화형 코팅액 개발에 관한 것이다. PVC 바닥상재용으로 사용되는 우레탄-아크릴 수지에 수용성 대전방지제와 항균제를 배합하여 오염 및 정전기로부터 보호하고 미생물에 의한 전염성질환을 예방할 수 있는 광경화형 내오염/항균 코팅액에 관한 실험을 수행하였다. 연구결과, 수지에 수용성대전방지제 15%와 항균제 1%를 혼합하여 제조한 코팅액을 Bar-coater No.12로 코팅한 표면이 전기저항($10^9\Omega/cm^2$), 내오염도(매직 Test, 먼지부착 Test) 및 부착력(100%) 양호, 항균성(99.99%)로 가장 좋은 물성을 보였다.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1013-1023
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• 2003

This study was performed to improve water quality of stream by applying hydraulic structures (weir and river bed material) made of porous concrete. The physical and chemical characteristics of porous concrete were measured to estimate application possibility of it in hydraulic structures and it was considered as a proper material for the hydraulic structures. In the results of comparison for the component of matters attached on the hydraulic structures made of porous and ordinary concrete, DW (dry weight) amount attached on porous concrete was 1.6 times higher than that on ordinary concrete under the condition of the same flow rate but influence by flow rate (difference of 10 times) was not shown. Therefore, we could understand that the material of media was more important in DW amount than flow rate. The rate of AFDM (ash free dry mass) to DW also was more at porous concrete than at ordinary concrete. Especially, the high rates of nitrogen and phosphorous in matters attached on porous concrete verify that they were removed by assimilation, adsorption and metabolism of periphyton. The removal percentage of SS, BOD, COD, T-N and T-P by hydraulic structures applying porous concrete compared with ordinary concrete was increased by 34.6%, 36.9%, 33.9%, 18.3% and 21.6%, respectively. Therefore, applying porous concrete to hydraulic structure is expected to contribute to improvement of stream water quality.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1284-1289
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• 2007

The Biological Activated Carbon (BAC) process in the water treatments represents a kind of biofiltration process which capabilities of bacteria to remove organic matters are maximized. It enables to eliminate organic matters and effectively reduce microbial regrowth potentials. As attached bacteria employ natural organic matter as a substrate, they are significantly dependent on indigenous microorganisms. In this study, characteristics of bacterial community by culturable and unculturable Methods have been conducted in a pilot plant using SAC in water treatment process at the downstream of the Nakdong River. Based on the results, HPC and bacterial- production for coal-based activated carbon material were $1.20{\sim}56.2{\times}l0^7$ cfu/g and $1.2{\sim}3.7\;mgC/m^{3}h$, respectively, in the SAC process. The highest level of attached bacteria biomass and organic carbon removal efficiency was found in the coal-based activated carbon. The genera Pseudomonas, Flavobacterium, Alcaligenes, Acilzetobacter, and Spingomonas were identified for each activated carbon material. Pseudomonas vesicularis was the dominant species in the coconut- and coal-based materials, where as Pseudomonas cepacia was the dominant species in the wood-based material. The Scanning Electron Microscope (SEM) observation of the activated carbon surface also found the widespread distribution of rod form and coccus. The community of attached bacteria was investigated by performing Fluorescent in situ hybridization (FISH) analysis. a group was dominant in coal, wood and coccunt-based materials, ${\alpha},\;{\beta}\;and\;{\gamma}$ group ranged from 27.0 ${\sim}$ 43.0%, 7.1 ${\sim}$ 22.0%, 11.3 ${\sim}$ 28.6%, respectively. These results suggest that a group bacterial community appears to be regulated removal efficiency of organic material in water treatment process.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.509-517
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• 2013

The purpose of this study is to assess the applicability of device-type stream coagulation process which combines physiochemical, biological processing for efficient improvement of water quality in small, middle-sized urban streams. The stream purification facility of this study is compose of pressure flotation type Micro Bubble Process(MBP) to remove TSS and TP and conduit line type Attached Microbial Pipe System(AMPS) to remove BOD. Test conditions of each device were set by floating stay time and change of ultra fine bubble injection amount of MBP, and change of AMPS stay time. Also, removal efficiency of pollution sources of each process were assess by change of season. As result of continuous operation of each process, MBP showed a maximum of TSS 83.69%, TP 95.15% process efficiency and AMPS showed a maximum of 52.95% TBOD5 removal efficiency. Also as result of circular operation of each process, MBP showed a maximum of TSS 69.75%, TP 70.17% process efficiency and AMPS showed a maximum of 68.58% TBOD5 removal efficiency. Therefore, it is considered that this stream coagulation process is effective in improving the water quality of streams in urban areas.

• Research in Plant Disease
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• v.24 no.1
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• pp.33-40
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• 2018

This study was conducted to evaluate the antifungal activity of 19 agro-materials that have been registered for organic cultivation in Korea, after inoculation of pear leaves with Venturia nashicola and Gymnosporangium asiaticum. In V. nashicola, most of the nine agro- materials containing sulfur and copper completely inhibited spore germination, and some of the spores that germinated did not form appressoria. However, in only lime sulfur, Neobordeaux (cupric sulfate), and Wheengaris (sulfur)showed antifungal activity against G. asiaticum. Among the agro-materials containing plant extracts, Wheengarujaba (wood vinegar+spirits+rhubarb) inhibited conidial germination in V. nashicola and G. asiaticum by 100% and 71.6%, respectively. Among the agro-materials containing antifungal microorganisms, Cheongotan (Streptomyces griseus) reduced spore germination rate of V. nashicola to 88.8%; moreover, formation of appressoria or intracellular accumulation was not observed. Application of Topsid (Paenibacillus polymyxa) reduced spore germination rates in V. nashicola and G. asiaticum to 71.0% and 90.6%, respectively, and the formation of appressoria was not observed. Studying the antifungal activity of agro-materials because of cumulative applications under the field conditions is necessary, owing to their contact fungicidal effect and the induced-resistance by microbial metabolites and natural compounds.

• Journal of Life Science
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• v.32 no.2
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• pp.142-147
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• 2022

Oxysterols are known to be involved in the physiopathology of atherosclerosis. Since 7-ketocholesterol (7-KC) is found in large amounts in oxysterols and in atherosclerotic plaque, the study on how 7-KC may affect monocyte differentiation induced by phorbol myristate acetate (PMA) in the monocytic cell line, THP-1, is essential. 7-KC induced a dose-dependent reduction in cell proliferation without inducing cytotoxicity, and the substantial staining of Nile red demonstrates the increased absorption of intracellular lipids. Although 7-KC itself did not increase cell adhesion, it markedly decreased the adhesion of cells treated with PMA. Furthermore, by observing the effect of 7-KC on phagocytosis using fluorescent-labeled latex beads, 7-KC's ability to abolish phagocytosis in PMA-stimulated macrophages was illustrated. The effect of 7-KC on the expression of selected protein markers on the process of differentiation induced by PMA in THP-1 cells was also examined. 7-KC inhibited expression of ICAM-1, CD11a, SR-A1, and SR-B2 (CD36) in PMA-stimulated THP-1 cells. Conversely, 7-KC drastically increased the expression of SR-D1 (CD68)in PMA-stimulated THP-1 cells. In conclusion, these results suggest that 7-KC modulates monocyte differentiation and activation via the intracellular accumulation of lipid droplets.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.206-214
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• 2005

This study was initiated to evaluate efficiencies of suspenced-growth processes(CAS; Conventional Activated Sludge, MLE; Modified Ludzack-Ettinger) and hybrid process(Modified-Dephanox) on removal of organic matter(C), nitrogen(N) and phosphorus(P) in municipal wastewater. M-Dephanox process was designed to improve the performance of Dephanox process on denitrification efficiency. As the results, removal efficiencies of total chemical oxygen demand(TCOD), total nitrogen(T-N) and total phosphorus(T-P) in M-Dephanox process, which is hybrid process, were 12,3, 18.6 and 28.2% higher than those in MLE, which is suspended-growth process. The better removal efficiencies of TCOD, T-N and T-P in M-Dephanox than those in MLE result that M-Dephanox is not only hybrid or multi-sludge process but also process using biosorption mechanism which is possible to use organics in denitrification, effectively. Ammonia removal efficiency in nitrification reactor of M-Dephanox was 96.7% at short hydraulic retention time(HRT) of 2 hr which was 3 hr more short HRT than that(HRT 5 hr) reported in other related papers. This indicates that M-Dephanox process can reduce HRT of whole process.

• Korean Journal of Microbiology
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• v.15 no.2
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• pp.77-84
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• 1977

The yeast population on 14 species of seaweeds and in water estimated by cultural mothods over a 5-month period in south-west in Korea, Nine species of yeasts, comprising unidentified one, and one of yeast-like fungi were identified. Fifty phycase were attributed to the difference of cultural method between the present work and earlier repoeters and, to some exent, the higher number of Rhodotorula glutinis which had a prior adaptation to the release of inhibitory polyphenolic materials. Although, to what extent, all division of algae showed a similar variation in yeast population, correlated with month, the rapid decrease of yeast population in August seems to be the cause of exposure of heat irradiation in this month. The cultural estimate of per se fltration without double filter and one of unidentified species are discussed.