• 대한의용생체공학회:의공학회지
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• 제14권3호
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• pp.227-234
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• 1993

Hemofilter was optimally designed and manufactured using polysulfone hollow fiber mem- brane with surface area of 0.6mE Molecular weight cut-off of the hemofilter was measured with polyethylene glycol and dextran aqueous solutions of various molecular weights and it was ranged from 9,500 to 38,900. Ultrafiltration rates were measured with pure water in a static system and flowing system. The clearance of urea, creatinlne, and vitamine BIB were measured using aqueous solutions.

• 상하수도학회지
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• 제23권4호
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• pp.459-469
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• 2009

It is well known that coagulation pretreatment can reduce foulants prior to membrane filtration. The purpose of this research was to investigate the effects of coagulation on fouling of ceramic microfiltration membrane($0.1 {\mu}m$) using pilot plant of $150m^3/day/train$ capacity. Train A membrane system has pretreatment process of ozonation and coagulation while train B has only coagulation. Two types of coagulation operation were investigated: back mixer(rapid mixing with or without slow mixing) which is a conventional mechanically stirred mixer and an inline static mixer. Ozone dose rate for train A was 1 mg/L and ozone contact time was 12 min. The coagulation dose(PACl 10% as $Al_2O_3$) rate was changed 20~40 mg/L according to experimental schedule. In this experimental conditions, the coagulation of back mixer type with rapid mixing(GT=72,000) and slow mixing(GT=45,000) was the best effective in reduction of ceramic membrane fouling regardless preozonation. Especially, the effect of inline static mixer was sensitive to change in water quality. Ozonation mainly affected irreversible fouling rather than reversible fouling in accordance with less adsorption of NOM on the membrane surface. Thus, the increase rate of the nomalized TMP(trans membrane pressure) at $25^{\circ}C$ for train A was relatively lower than that of train B under same coagulation process with same coagulant dosage. The best performance of ceramic membrane appeared in case of combined process with ozonation, therefore this integrated process is able to archive less coagulant dosing and secure a stability of ceramic membrane system.

• 상하수도학회지
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• 제12권1호
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• pp.102-107
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• 1998

This study was conducted to investigate how the pore sizes of MF and UF membranes affected the removal efficiencies. The experimental results were compared with those obtained from the existing sand filter to select the optimum membrane. Turbidity of the raw water was adjusted to 10, 30, 50, 100, and 200NTU. The removal efficiencies of the turbidity and SS were nearly 100% for all membranes applied. Not membrane differences in the removal efficiencies of dissolved organics were also found. Thus, MF membrane with pore size $0.1{\mu}m$ was selected to obtain satisfactory removal efficiencies of turbidity and bacteria. Permeable flux was also considered. The $0.1{\mu}m$ MF membrane system was operated in the treatment plant to compare the results with those obtained from the existing sand filter. Turbidity, SS, $KMnO_4$ consumption, and number of coliform were chosen to be compared. Because there were not much differencies in the quality of the treated water, the existing coagulation-sedimentation-filtration process might be replaced and upgraded by simpler membrane process.

• 환경위생공학
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• 제15권3호
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• pp.31-36
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• 2000

Conventional membrane systems was difficults to treatment for the swine waste water. Technological advances in membrane filtration systems have created opportunity for the swine wastewater to treat effluent streams in order to meet stricter environmental constraints. "Vibratory Shear Enhanced Processing(VSEP)" developed by new logic international makes it possible to filter effluent streams without the fouling problem exhibited by conventional membrane systems. Various kinds of waste water occurred to and swine wastewater experiment with "VSEP" set up conventional reverse osmosis membrane (ACM-4, ESPA, BW-30). The results were as followes : Treatment efficiency for the input COD(From $332mg/{\ell}$ to $4,968mg/{\ell}$) was 98%. Treatment efficiency for the input SS(From $140mg/{\ell}$ to $4,040mg/{\ell}$) was 100%(All together). Treatment efficiency for the input T-N(From $155mg/{\ell}$ to $934mg/{\ell}$) was 97%~99.8%. Treatment efficiency for the input T-P(From $28.6mg/{\ell}$ to $132mg/{\ell}$) was 99.7% and up. ESPA membrane excels three types of reverse osmosis membranes applied VSEP in removal efficiency.

• 상하수도학회지
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• 제26권1호
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• pp.21-27
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• 2012

This study evaluated the performance of a thermophilic two-phase anaerobic digestion (TTPAD) coupled with membrane process treating garbage leachate. The pilot-scale treatment system is consisted of thermophilic acidogenic reactor (TAR) and thermophilic methanogenic reactor (TMR) coupled with an ultrafiltration (UF) membrane unit. The hydraulic retention time of TAR and TMR were 4 and 20 days, respectively. Effluent TCOD and SCOD of the TTPAD were $25\;{\pm}\;6\;and\;12\;{\pm}\;3$ g/L, respectively, and the corresponding TCOD and SCOD removal efficiencies were 77% and 81%, respectively. Propionate was major acids as 75% in the effluent. Scum formation was not observed in TTPAD, which might be resulted from complete lipid degradation. However, TTPAD was appeared to be sensitive to free ammonia toxicity. The UF membrane was operated with constant pressure filtration at average TMP 1.3 atm. Permeate flux had a range of 15-30 $L/m^2/hr$. With UF membrane, TCOD removal increased from 77% to 93%, and this SS free effluent would be beneficial to subsequent processes such as ammonia stripping.

• 멤브레인
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• 제22권5호
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• pp.352-358
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• 2012

본 연구는 pressure retarded osmosis (PRO) 분리막의 구조적 특성이 미치는 영향에 대하여 수행되었다. 이를 위해, 유사 분자구조를 가지며 자유부피는 차이가 나는 BPS-XX, BisA-XX가 선택되었다. BPS-XX와 BisA-XX는 축중합 반응을 통해 합성되었으며, 또한 더 세분화된 결과를 위해서 20~60 mol.%로 술폰화되었다. 자유부피의 변화에 따른 분리막의 특성을 입증하기 위해서 몇 가지 특성평가가 진행되었다. 연구 결과에서 동일 분자구조에서 자유부피가 증가하면 막의 투과도가 증가하였고, 선택도는 감소하였다. 본 연구의 투과도-선택도 결과에서, 분자의 기본 구조와 자유부피 조절에 따라서, 고 투과도와 선택도를 가진 막을 제조 가능함을 알 수 있었다.

• 멤브레인
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• 제32권1호
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• pp.50-56
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• 2022

본 연구에서는 유기용매용 나노여과막 (Organic Solvent Nanofiltration, OSN)의 유기용매 투과 및 분리성능을 분석하였다. 비극성용매에 적합한 Puramem (PM) 시리즈 분리막의 소재를 분석한 후 다양한 유기용매 분위기에서의 투과성능을 데드엔드셀로 측정하였다. PM 시리즈 분리막은 극성용매 대비 비극성용매에서 더 높은 투과도를 보였으며, 용질의 종류 및 분자량에 따라 매우 독특한 배제성능을 보이는 것을 확인하였다. 이는 기존 수처리에 적용되는 Solution-diffusion 투과모델이 OSN 투과모델에는 적합하지 않다는 것을 알 수 있으며, solvent-solute-membrane 간의 상관관계를 더 정확하게 반영할 수 있는 새로운 인자가 필요하다는 결론을 낼 수 있다.

• 한국식품영양과학회지
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• 제20권2호
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• pp.187-196
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• 1991

Aging is the progressive accumulation of changes with time associated with responsible for the ever-increasing susceptibility to disease and death which accompanies advancing age. Lipid peroxides easily produced in the membrane system by the chain reaction of free radicals which occurred from various environmental factors. The amount of lipid peroxides produced in biological system increased with aging process, and lipid peroxidation damages involved in aging process and pathological disorders. Although lipid peroxides have such deleterious effects on the organisms, there are numerous substances and mechanisms which prevent the reaction of peroxide formation and protect the subject from its toxicity. This review provides an overview of how does lipid peroxidation of unsaturated lipids take place by free radical, and what is the intervention of lipid peroxides in pathogenesis of some human diseases, and also how does food restriction influences the aging process and various pathological disorders. The major focus of this paper is to review the evidence indicating that food restriction retards the aging process, and possible mechanisms of its actions. Therefore, it discussed the effects of age and food restriction on life-span, membrane yield, lipid peroxidation, fatty acid composition and peroxidizability, cholesterol and triglyceride levels, prostaglasndin and thromboxane synthesis, which may be concerned with blood flow, membrane fluidity, homeostasis and glomerular filtration rate in living body.

• 한국물환경학회지
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• 제33권4호
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• pp.403-408
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• 2017

In these days, wastewater reclamation and seawater desalination play essential role in addressing the challenge of worldwide water scarcity. Particularly, reverse osmosis (RO) for seawater desalination process is commonly used due to less energy consumption than conventional thermodynamic systems. However, membrane fouling and electrical energy consumption during operation of RO system for seawater desalination haver continued to be a obstruction to its application. In this study, therefore, wastewater secondary effluent is used for osmotic dilution of seawater. Firstly, fouling behaviour of RO by simulating wastewater effluent in osmotic dilution process was measured and we calculated energy consumption of overall desalination process by theoretical equations and commercial program. Our results reveal that RO membrane fouling can be efficiently controlled by pre-treatment systems such as nano filtration (NF) or forward osmosis (FO) process. Especially FO system for osmotic dilution process is a non-pressurized membrane system and, therefore, the operating energy consumption of overall desalination system was the lowest. Moreover, fouling layer on FO membrane is comparatively weak and reversible enough to be disrupted by physical cleaning. Thus, RO system with low salinity feed water through FO process is possible as a less energy consuming desalination system with efficient membrane fouling control.

• Membrane and Water Treatment
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• 제8권5호
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• pp.499-515
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• 2017

The purpose of this study was to investigate membrane fouling caused by microalgal cells in submerged membrane systems consisting of polymeric and ceramic microfiltration membranes. In this study, one polymeric (flat-sheet, pore size: $0.2{\mu}m$) and two ceramic (flat-sheet, pore size: $0.2{\mu}m$ and cylindrical, pore size: $1{\mu}m$) membranes were used. Physical cleaning was performed with water and air to determine the potential for reversible and irreversible membrane fouling. The study results showed that substantial irreversible membrane fouling (after four filtration cycles, irreversible fouling degree 27% (cleaning with water) and 38% (cleaning with air)) occurs in the polymeric membrane. In cleaning studies performed using water and air on ceramic membranes, it was observed that compressed air was more effective (recovery rate: 87-91%) for membrane cleaning. The harvesting performance of the membranes was examined through critical flux experiments. The critical flux values for polymeric membrane with a pore size of $0.20{\mu}m$ and ceramic membranes with a pore size of $0.20{\mu}m$ and $1{\mu}m$ were ${\leq}95L/m^2hour$, ${\leq}70L/m^2hour$ and ${\leq}55L/m^2hour$, respectively. It was determined that critical flux varies depending on the membrane material and the pore size. To obtain more information on membrane fouling caused by microalgal cells, the characterization of the fouled polymeric membrane was performed. This study concluded that ceramic membranes with a pore size of $0.2-1{\mu}m$ in the submerged membrane system could be efficiently used for microalgae harvesting by cleaning the membrane with compressed air at regular intervals.