• KSBB Journal
• /
• v.4 no.2
• /
• pp.177-184
• /
• 1989

In separating mycelia from antibiotic fermentation broths, high permeate flux was obtained by cross-flow filtration using modified regenerated cellulose membrane. The flux was increased most effectively by increasing the flow rate. There existed a critical mycelium density (about 20% PMV) at which the highest flux was observed. In a batchwise concentration of the fermentation broth, the system suffered from a severe fouling problem, which was relieved drastically by applying diafiltration technique, although it increased the permeate volume. A combined concentration/diafiltration process was ideal in keeping relatively high flux together with a high product recovery yield. The best result was obtained by starting diafiltration after concentrating the broth to 20% PMV. By doing so, a 98% product recovery yield was achieved in the shortest time while keeping the permeate volume at a minimum level.

• Environmental Engineering Research
• /
• v.9 no.5
• /
• pp.238-247
• /
• 2004

The objective of this study was to develop kinetic model for the MBR and investigate kinetic characteristics of the gravitational flow transverse direction MBR system. Kinetic model was derived by mass balance of substratc and biomass combined with empirical membranc filtration rerm for the MBR. To find kinctic values, permeale flux and COD removal were analyzed through the laboratory, MBR operation as different solids retention times. Permeate flux was ranged 2.5-5.0 LMH (L/m$^2$/hr) as sludge characteristics in each run. Although the soluble COD in the bioreactor was changed, the effluent COD was stable as average 99% removal rate during the experimental periods. Y$_g$ of this MBR system was higher than those of cross-flow MBR processes. The kinetics of this MBR showed that smaller k, larger b, and larger K$_s$ values than the conventional activated sludge process. These results indicated that substrate was used for cell maintenance rather than growth in this MBR system.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.332.2-333
• /
• 2002

Three alkaline proteases. designated JB-1. JB-2, and JB-3, are extracellular enzymes produced by Bacillus spp. JB411 which was isolated korean soil. They were separated by DEAE-sepharose CL-6B gel. and further purified using ammonium sulfate precipitation. ultra membrane filtration. and Ultrogel AcA gel filtration. The optimun pH values of proteases IB-1. JB-2. and JB-3. were shown to be 9.5. 9.5 and 7.5. respectively. All three proteases were stable in the pH range of 5-11. (omitted)

• Journal of environmental and Sanitary engineering
• /
• v.12 no.2
• /
• pp.65-74
• /
• 1997

The purpose of this study was to investigate the removal effect and variation of contaminated water by various water treatment processes using sediment filter, activated carbon, photocatalysis, reverse osmosis, ultra violet sterilizer and ultra filtration. The removal effect of chloride and trace metal was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon but high in impregnated activated carbon. The removal effect of TCE was low in sand and ultra filter system as compared with activated carbon. Ultra filtration process was effective for purify agricultural water without E.coli. Reverse osmosis was effective to remove heavy metal and activated carbon was effective to remove halogenated organic chemical compound. The flux and the removal effect of COD in spiral wound ultrafilter were higher than the hollow fiber ultrafilter.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.9
• /
• pp.542-547
• /
• 2017

This paper was to analyze the membrane characterization of hydrophilicity, surface morphology and membrane chemical anlysis of three commercial microfiltration/ultrafiltration membranes, and evaluate the filtration performance of a seawater to assess the availability for pretreatment of desalination process. From the results of contact angle, Mem-3, fabricated with polyacrylonitrile, was highly hydrophilic. It find out that Mem-3 has more anti-biofouling property. In Field emission scanning electron microscope (FESEM), Mem-1 (polyethylene) and Mem-2 (Polyvinylidenefluoride) showed the sponge-like shape and Mem-3 showed finger-like shape. Membrane chemical analysis by energy dispersive spectrometer (EDS) presented that Mem-2 was mostly fluoride and Mem-3 had s high ratio of N (32.47%) due to the nitrile group. The permeation flowrate per time on suction pressures using deionized water (D.I. water) tends that permeation rate of Mem-3 more increased when the pressure was increased compared to other membranes. From the results of turbidity and total suspended solids (TSS) removal, turbidity of permeate was 0.191 NTU to 0.406 NTU and TSS was 2.2 mg/L to 3.0 mg/L in all membranes, indicating that it was not suitable for the pretreatment of seawater desalination by short-term experiments.

• Membrane Journal
• /
• v.6 no.2
• /
• pp.101-108
• /
• 1996

The oxidation/degradation efficiency of formic acid through the photoelectrochemical reaction has been investigated as a basic research in order to develope the process for degrading toxic organic compounds dissolved in water. A $TiO_{2}$ photoelectro-membrane reactor for purification of water, in which filtration as well as photoelectrocatalytic oxidation of organic compounds could be carried out simultaneously, was developed. Porous $SnO_{2}$ tubes prepared by slip casting and commercial porous stainless steel tubes, being electrically conductive, were used as not only supports but also working electrodes. The UV light with the wavelength of 365 nm was applied as a light source for photocatalytic reactions. The photoelectrocatatytic composite membranes were prepared by coating the support surface with the $TiO_{2}$ sol of pH 1.45. The oxidation efficiency of formic acid increased with the reaction time and the applied voltage, but was almost independent of the solution flux. The results showed that more than 90% of formic acid could he dograded at 27V using the $TiO_{2}$/stainless steel composite membrane, while about 77% in case of the $TiO_{2}/SnO_{2}$ Composite membrane. It was also concluded that the oxidation efficiencies of formic acid could be significantly improved by about 6~7 times by the photoelectrochemical reaction in comparison with those by the photocatalytic reaction only.

• Membrane Journal
• /
• v.21 no.2
• /
• pp.163-170
• /
• 2011

Membrane fouling control in water treatment may be the main obstacle for wider implementation and lower cost. A novel fluorescent spectroscope sensor device for membrane fouling integrity monitoring has been developed and evaluated in this study. PSf membranes for water treatment has been fabricated with three types of organic fluorescent materials, OB, FP, KCB. The fluorescent signal from membrane surface was analyzed throughout the filtration process. It was found that the fluorescent signal due to the membrane fouling decreased and the developed device is reliable for membrane fouling monitoring.

• Membrane Journal
• /
• v.26 no.1
• /
• pp.55-61
• /
• 2016

Organic fouling observed in submerged membrane filtration as a pretreatment for seawater desalination increases energy consumption for membrane operation because of requiring frequent chemical cleaning and membrane replacement. In membrane pretreatment for seawater facing with algae blooms, membrane fouling was observed in submerged microfiltration using sodium alginate model compound which is one of the main components of extracellular polymeric substances. Without aeration, aglinate fouling increased with its concentration while aeration reduced the alginate fouling effectively regardless of its concentration tested. In the absence of aeration, alingate fouling tended to be decreased with increasing calcium concentration. However, this effectiveness was reduced by increasing sodium chloride concentration. At high concentration of sodium chloride and calcium similar to the seawater conditions, aeration reduced initial fouling. However, as time progressed, the effect of increased airflow rate on fouling reduction was not significant, implying that optimum airflow rate to control alginate fouling in submerged microfiltration can exist.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.5
• /
• pp.353-358
• /
• 2011

In this study, ammonia removal characteristics in membrane contactor system under various operating conditions were evaluated. The mass transfer coefficient was used to quantitatively compare the effect of various operation conditions on ammonia removal efficiency. Effective removal of ammonia was possible with the tubular PTFE membrane contactor system at all tested conditions. Among the various operation parameters, contact time and solution pH showed significant effect on ammonia removal mechanism. Overall ammonia removal rate was not significantly affected by influent suspended solution concentration unlike other pressure driven membrane filtration processes. Also the osmotic distillation phenomena which deteriorate the mass transfer efficiency can be minimized by preheating of strip solution. Membrane contactor system can be a possible alternative to treat high strength nitrogen wastewater by optimizing operation conditions such as stripping solution flow rate, influent wastewater temperature, and influent pH.

• Membrane Journal
• /
• v.20 no.4
• /
• pp.320-325
• /
• 2010

This paper was carried out to study the preparation condition and the permeation flux of reinforced poly(vinylidene fluoride) (PVDF) hollow fiber microfiltration (MF) membrane with the solvent, additive, second miscible polymer, and preparation condition used poly(vinylidene fluoride) (PVDF) such as a material with the excellent chemical stability and the milder preparation condition. The performance of the reinforced MF membrane prepared obtained the average $0.3{\mu}m$ pore size, $42kg_f/cm^2$ tensile strength, and the high water flux of 600 LMH. The change of membrane performance with various additives was considerably affected on the water flux and rejection. For hydrophilic modification of hydrophobic PVDF MF membrane, the MF membrane might be prepared with a prefer water flux and rejection by addition of hydrophilic poly(methyl methacrylate) (PMMA).