• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.69-71
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• 1994

섬유폐수는 합성유기물인 염료와 발호공정에서의 호제가 다량으로 함유되어 있어 기존의 생물학적 처리법에 의한 처리가 용이하지 않다. 게다가 섬유산업은 여타산업에 비해 다량의 물을 소비하는 산업이다. 그동안의 산업의 고도 발전에 따라 앞으로는 물부족현상이 심해질 전망이며, 환경보전 및 보호에 대한 의식이 고취됨에 따라 이러한 섬유폐수의 처리도 이제까지와는 다른 새로운 방법으로 그 효율을 극대화할 필요성을 느끼게 되었다. 이에 따라 본 연구에서는 막분리 공정으로서 한외여과, 역삼투 공정을 이용하여 염색$\cdot$제직폐수를 고도처리하여 재활용이 가능토록 하였으며, 이를 바탕으로 염색$\cdot$제직폐수의 고도처리를 통한 재활용 시스템을 설계하였다.

• KSBB Journal
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• v.11 no.3
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• pp.347-352
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• 1996

The enzyme deactivation in a membrane recycling system for the simultaneous saccharification and fermentation(SSF) was studied under various temperature and pressure. The optimum molecular weight cut off(MWCO) of the ultrafiltration membrane for recycling cellulase and ${\beta}$-glucosidase was 50,000. When the cellulase was recycled continuously through the membrane system, it was not deactivated. But the activity of ${\beta}$-glucosidase was decreased with an increase in operating temperature and transmembrane pressure. After 720 minutes at $42^{\circ}C$ and 24.8 psig , the activity of ${\beta}$-glucosidase was reduced by 35% of the initial activity. Such tendencies could be well explained by the results of highly induced shear at the fiber surface of membrane when temperature and transmembrane pressure became higher.

• KSBB Journal
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• v.5 no.4
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• pp.335-339
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• 1990

In order to develop economic processes for ethanol production from starch, a simultaneous saccharification and fermentation(SSF) process using Zymomonas mobilis and amyloglucosidase (AMG) was studied in semibatch modes using cell recycle. The cell recycle was carried out by adopting two different methods; microfiltration and settling. The cell recycle using microfiltration revealed higher productivity(5.4 g/l/h) than that using a settler(4.3 g/l/h). Taking the large-scale ethanol fermentation into account, the semibatch process using microfiltration system appeared most promising among others with respect to ethanol productivity, feasibility of scale-up and simplification of operation.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.17-24
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• 2005

This study was carried out to investigate the removal efficiency of an intermittently aerated nonwoven fabric filter bioreactor fed continuously with domestic sewage. The hydraulic retention time(HRT) of the reactor was reduced from 12 hrs to 10 hrs to 8 hrs during an experimental period of 17 months. In order to search an optimum aeration/nonaeration time ratio for the nitrogen removal at each HRT, the cycle times of 3, 2 and 1 hr were tested at the aeration/nonaeration time ratio of 1. Then, the aeration/nonaeration time ratio was changed from 50 min/70 min to 40 min/80 min to 30 min/90 min at the cycle time of 2 hr which showed the best nitrogen removal. During the experimental period, the effluent SS concentration was always below 1.2 mg/L with more than 95% of BOD removal efficiency. The highest nitrogen removal of 90.1% was observed at the aeration/nonaeration time ratio of 40 min/80 min at the HRT of 10 hr. Oxidation-reduction potential could represent the degree of the nitrification and denitrification reaction in the reactor.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.156-160
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• 1997

The combination of biological wastewater treatment process and membrane separation has many advantages such as better effluent quality and system stability over the conventional biological wastewater treatment process. In this study, direct membrane separation using nonwoven fabric was applied to biological wastewater treatment. A nonwoven fabric module was submerged in the aerated bioreactor. And accumulated biomass in the bioreactor was separated by suction. The system was operated with various condition to investigate pollutant removal efficiencies and flux. After formation of biomass layer on nonwoven fabric surface, a day, the stable effluent water quality was obtained. The flux decreased at a high suction pressure faster than a low pressure. The stable flux was obtained at the pressure of $21{\sim}25cmHg$. In spite of variation of hydraulic retention time, organic loading rate, the removal efficiencies of BOD, $COD_{Cr}$. $COD_{Mn}$ were very high as follows : $95.2%(0.14{\sim}0.97\;BODKg/m^3/day)$, $86.0%(0.17{\sim}1.39\;COD_{Cr}Kg/m^3/day)$, $90.0%(0.097{\sim}0.61\;COD_{Mn}Kg/m^3/day)$.

• Membrane Journal
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• v.34 no.1
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• pp.38-49
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• 2024

Wastewater treatment using membrane bioreactors has been extensively used to alleviate water shortage and pollution by improving the quality of the treated water discharged into the environment. However, membrane biofouling persistently holds back an MBR process by reducing the process efficiency. Herein, we synthesized carbon nanospheres (CNSs) with many hydrophilic oxygen groups and utilized them as an additive to prepare high-performance ultrafiltration (UF) membranes with hydrophilicity and porous pore structure. CNSs were found to form crescent-shaped pores on the membrane surface, increasing the mean surface pore size by about 40% without causing significant defects larger than bubble points, as the CNS content increased by 4.6 wt%. In addition, the porous pore structure of CNS composite membranes was also attributable to the CNS's isotropic morphologies and relatively low particle number density because the aforementioned properties contributed to preventing the polymer solution viscosity from soaring with the loading of CNS. However, too porous structure compromised the mechanical properties, such that CNS2.3 was the best from a comprehensive consideration including the pore structure and mechanical properties. As a result, CNS2.3 showed not only 2 times higher water permeability than CNS0 but also 5 times longer operation duration until membrane cleaning was required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3517-3522
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• 2011

Contamination of public bath water by waterborne pathogens can cause disease outbreaks and contribute to background rates of disease. The aim of this study is to determine the prevalence of waterborne pathogens in public baths. A total of 30 water samples were collected from 30 different public baths in seoul, Korea. Pathogens in water samples were concentrated by 0.45 ${\mu}m$ nitrocellulose membrane filter, analyzed by both cultivation and polymerase chain reaction-reverse blot hybridization (PCR-REBA) of partial 16S rRNA gene. Various microorganisms including Escherichia coli and Shigella spp. were identified by microbiological cultivation. E. coli, Shigella spp., Salmonella spp., Pseudomonas spp. and Mycobacterium spp. were identified by PCR-REBA. Our results suggest that appropriate hygiene practice and continuous monitoring is needed for reducing health risk associated with public bath houses.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.155-163
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• 2017

Membrane filtration has become more popular in drinking water treatment recently, since the filtration can control not only particulate matters but also pathogenic microorganisms such as giardia and cryptosporidium very effectively. Pilot-scale ($120m^3/d$ of treatment capacity) and test-bed ($25,000m^3/d$ of treatment capacity) microfiltration experiments were conducted to find optimum operating mode and the critical flux. Optimum operating mode of pilot-test was assessed as inflow 1.0 min, filtration 36.5 min, air backwash 0.9 min, backwash 1.0 min and outflow 1.0 min with 50 LMH ($L/min{\cdot}m3^$) of critical flux. Critical Flux was calculated to be $50L/m^2-h$ (within TMP 0.5 bar) based on the increase formula of the transmembrane pressure difference according to the change of time at Flux 20, 40, 56 and 62 LMH in pilot operation. Chemical cleaning was first acid washed twice, and alkali washing was performed secondarily, and a recovery rate of 95% was obtained in the test-bed plant. The results of operating under these appropriate conditions are as follows. Turbidity of treated water were 0.028, 0.024, 0.026 and 0.028 NTU in spring, summer, autumn and winter time, respectively. Microfiltration has superior treatment capability and performance characteristics in removing suspended solids and colloidal materials, which are the main cause of turbidity and important carrier of metal elements, and it has shown great potential in being an economically substitute to traditional processes (sand filtration).

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.230-236
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• 2016

Economic growth has increased the living standards around the world. Water pollution, in particular, is a public relations issue because it poses a direct threat to everyone's lives. As of recently, the production of taste and odor (T&O) compounds has been a common problem in the water industry. The adsorption process using granular activated carbon (GAC) has been the most widely used process. The objectives of this study were to evaluate the microorganisms before and after the backwashing of GAC and to identify the species of the microorganisms found. Five dominants microorganisms were confirmed after the microfiltration process from backwashing of GAC, and the dominant bacterial species were found to be ${\beta}$-proteobacterium species, Porphyrobacter donghaensis, Polaromonas rhizophaerae, Hydrogenophaga species, and Pseudonocardia species. However, when UV treatment after microfiltration was performed, Hydrogenophaga species and Psedonocardia species were eliminated. Herein, I conclude that the UV treatment post microfiltration process is more efficient than microfiltration process alone. The findings of this study may provide useful information regarding the management of microfiltration process.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.140-143
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• 2004

Membrane bioreactors (MBRs) used for water purification are based on the association of a bioreactor, within which a culture of microorganisms degrades the polluting compounds, and a membrane filtration separator. The use of a porous barrier usually ensures the disinfection of the effluent.(omitted)