• Membrane and Water Treatment
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• v.5 no.2
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• pp.73-86
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• 2014

Membrane fouling is a major challenge limiting the use of membrane applications. In this study high induced shear rates were utilized at the membrane surface in order to reduce the organic and inorganic scaling by using the torsional vibration of flat sheet membranes. The performances of a vibratory shear-enhanced processing (VSEP) system for the ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membrane filtration of industrial dairy wastewater were investigated. The vibration and non-vibration methods were compared with the same membrane and operational parameters during the purification of real dairy industrial process wastewater. In the initial experiments, short-term tests were carried out in which the effects of vibration amplitude, recirculation flow rate and transmembrane pressure were measured and compared. The permeate flux, turbidity, conductivity and chemical oxygen demand (COD) reduction of dairy wastewater were investigated by using UF, NF and RO membranes with vibration and non-vibration methods. In the subsequent experiments, concentration tests were also carried out. Finally, scanning electron microscopy (SEM) revealed that the vibration method gave a better performance, which can be attributed to the higher membrane shear rate, which reduces the concentration of solids at the membrane, and the transmission.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.4
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• pp.445-448
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• 2008

The application of the membrane filtration process has been increased for the drinking water treatment system because of excellent quality of treated water compared with the sand filtration process. The selection of suitable pre-treatment processes and optimum flux according to the characteristics of raw water are important factors for the design of membrane processes. In this study, the most efficient pre-treatment processes for drinking water was selected by investigating the effects of pre-treatment processes on the operational stability of the membrane filtration process. Both lab-scale and pilot-scale experiments were conducted. In the lab-scale test, the effect of pre-treatment processes on the stability of the membrane filtration process was investigated indirectly by comparing the performance of membrane flux for raw water, pre-treated water, and membrane permeated water. In the pilot-scale test, the usefulness of prefiltration processes was assessed by comparing the performance of single membrane process and hybrid coagulation-membrane process. The results indicated that the coagulation process contributed to the stabilization of trans-membrane pressure (TMP) by removing contaminants on membranes, though the pre-filtration process had little effect on the TMP.

• Membrane and Water Treatment
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• v.6 no.1
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• pp.15-26
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• 2015

The compact structure and high-quality effluent of membrane bioreactors make them well-suited for decentralized greywater reclamation. However, the occurrence of membrane fouling continues to limit their effectiveness. To address this concern, a unique membrane module configuration was developed for use in a decentralized greywater treatment system. The module featured local aeration directly below a series of inclined membrane bundles, giving the overall module a twisted appearance compared to a module with vertically orientated fibres. The intent of this design was to increase the frequency and intensity of collisions between rising air bubbles and the membrane surface. Material related to the construction of custom-fit modules is rarely communicated. Therefore, detailed design and assembly procedures were provided in this paper. The twisted module was compared to two commercially available modules with diverse specifications in order to assess the relative performance and marketability of the twisted module with respect to existing products. Contaminant removal efficiencies were determined in terms of biochemical oxygen demand, chemical oxygen demand, ammonia, total nitrogen, total phosphorus, and turbidity for each module. Membrane fouling was monitored in terms of permeate flux, transmembrane pressure, and membrane resistance. Following 168 h of operation, the twisted module configuration demonstrated competitive performance, indicating good potential for further development and commercialization.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.397-409
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• 2014

Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.

• Korean Membrane Journal
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• v.9 no.1
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• pp.12-17
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• 2007

We performed periodic water-back-flushing using permeate water to minimize membrane fouling to enhance permeate flux in tubular ceramic microfiltration system for water treatment of high turbid source. The filtration time (FT) = 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume $(V_T)\;=\;6.805L$. Also in the result of BT effect at fixed FT = 10 min and BT (back-flushing time) = 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_o$, and we could obtain the highest $V_T\;=\;6.660\;L$. Consequently, FT = 2 min and BT = 6 sec could be the optimal condition in water treatment of high turbid source above 10 NTU. However, FT = 10 min and BT = 20 sec was superior to reduce operating costs because of lower back-flushing frequency. Then the average quality of water treated by our tubular ceramic MF system was turbidity of 0.07 NTU, $COD_{Mn}$ of 1.86 mg/L and $NH_3-N$ of 0.007 mg/L.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.370-373
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• 2000

In this work, an extractive membrane bioreactor containing coulture broth of Burkholderia cepacia G4 PR1 constitutively expressing the TCE-degrading enzyme, tolune-ortho-monooxygenase(TOM), was used for the degradation of TCE. The membrane bioreactor operates by seperating the TCE-containing waste gas from the aerated biomedium, by which the air-stripping of TCE without degradation was overcome that could occur in conventional aerobic biological treatments of TCE-contaminated waste gases. This was achieved by a silicone rubber membrane which was coiled around a perspex draft tube. TCE from the gas phase diffuses across the silicone rubber membrane into microbial culture broth that was continuously fed from a separate aerobic CSTR. Therefore, TCE degradation occured without the TCE being directly exposed to the aerating gas stream. Of the TCE supplied to the membrane bioreactor, 72.6% was biodegraded during the operation of this system. To construct a mathematical model for this system, parameters describing microbial growth kinetics on TCE were determined using a CSTR bioreactor. Else parameters used for numerical simulation were determined from either indepedent experiments or values reported in the literature. The model was compared with the experimental data, and there was a good agreement between the predicted and the measured TCE concentrations in the system. To achieve a higher treatment efficiency, various operating conditions were simulated as well.

• KSBB Journal
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• v.11 no.2
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• pp.140-150
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• 1996

To develop a home-version assay system for plasma lipoprotein cholesterol, variables that can control the assay performance were optimized. The system was constructcd by using two major components: nitrocellulose membrane strip with immobilized enzymes (cholesterol esterase, cholesterol oxidase, and horseradish peroxidase); and sample carrier solution containing non-ionic detergent (Triton X-100) and chromogen (3,3'-diaminobenzidine). Once a sample combined with the carrier was absorbed from the bottom of the strip, cholesterol was delivered by capillary action to the immobilized enzymes and a sequential reactions took place. In the final reaction, the chromogen was oxidized and then generated a color as signal that was proportional to the concentration of cholesterol. The signal intensity was enhanced by optimizing conditions for the immobilization of enzymes and the chemical composition of carriel. Under these conditions, a dose-response curve was obtained and revealed a high sensitivity enough to measure the cholesterol in blood.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.12-27
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• 2004

Pretreatment process consisted of submerged hollow-fiber microfiltration(HMF) membrane and spiral-wound nanofiltration(SNF) membrane has been developed by NETEC, KHNP for the purpose of improving the impurities of liquid radioactive waste before entering Selective Ion Exchange System(SIES). The lab-scale combined system was installed at Kori NPP #2 nuclear power plant and demonstration tests using actual liquid radioactive waste were carried out to verify the performance of the combined system. The submerged HMF membrane was adopted for removal of suspended solid in liquid radioactive waste and the SNF membrane was used for removal of particulate radioisotope such as, Ag-l10m and oily waste because ion exchange resin can not remove particulate radioisotopes. The liquid waste in Waste Holdup Tank (WHT) was processed with HMF and SNF membrane, and SIES. The initial SS concentration and total activity of actual waste were 38,000ppb and $1.534{\times}10_{-3}{\mu}Ci/cc$, respectively. The SS concentration and total activity of permeate were 30ppb and lower than LLD(Lower Limit of Detection), respectively.

• Journal of Ship and Ocean Technology
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• v.12 no.1
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• pp.35-44
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• 2008

As arctic energy resource is attracting public attention, arctic shipping market will also be growing in large as expected to increase in LNG trade from Arctic area to the western countries by shipping. During the voyages through such routes, collision with icebergs may be possible. In the present report, ice collision analyses are carried out from a practical point of view to verify the safety of hull structural strength of LNG carriers equipped with GTT $MKIII^{TM}$ membrane type cargo containment system. From the results of collision analyses and the operation-friendly design concept of no-repairing of cargo containment system, a safe operating envelope against ice collision is proposed for LNG carriers of membrane type cargo containment system. Based on the currently proposed safety criteria, it is concluded that LNG carriers with membrane tank type can operate safely with regard to the integrity of CCS in regions where collision between LNG carrier and iceberg is expected.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.234-237
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• 2008