• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.322-328
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• 2011

This study was performed to investigate the characteristics of nutrient removal of municipal wastewater in the membrane bioreactor system with the different types of membrane. Membrane bioreactor consists of three reactors such as two intermittent anaerobic and the submerged membrane aerobic reactor with flat sheet and hollow fiber membrane, respectively. The removal efficiencies of $COD_{cr}$, BOD, SS, TN and TP on the flat sheet membrane bioreactor were 94.3%, 99.0%, 99.9%, 70.3% and 63.1%, respectively. In addition, The removal efficiencies of $COD_{cr}$, BOD, SS, TN and TP on the hollow fiber membrane bioreactor were 94.0%, 99.3%, 99.9%, 69.9% and 66.9%, respectively. The estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the flat sheet membrane bioreactor were $0.33kgVSS/kgBOD{\cdot}d$, $0.043mgNO_3-N/mgVSS{\cdot}d$, $0.031mgNH_4-N/mgVSS{\cdot}d$, and 0.144 kgP/d, respectively. In addition, the estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the hollow fiber membrane bioreactor were $0.30kgVSS/kgBOD{\cdot}d$, $0.067mgNO_3-N/mgVSS{\cdot}d$, $0.028mgNH_4-N/mgVSS{\cdot}d$, and 0.121 kgP/d, respectively. There was little difference between the flat sheet and hollow fiber on the nutrient removal efficiencies except SNR and SDNR. These differences between them were caused by the air demand to prevent the membrane fouling. The flux and oxygen demand for air scouring were $19.0L/m^2/hr$ and $2.28m^3/min$ for the flat sheet membrane, and $20.7L/m^2/hr$ and $1.77m^3/min$ for the hollow fiber membrane on an average.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.325-334
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• 2023

Membrane bioreactor (MBR) provides the benefits on high effluent quality and construction cost without the secondary clarification. Despite of these advantages, fouling, which clogs the pore in membrane modules, affects the membrane life span and effluent quality. Studies on the laboratory scale MBR were focused on the control of particulate fouling, organic fouling and inorganic fouling. However, less studies were focused on the control of biofouling and microbial aspect of membrane. In the full scale operation, most MBR produces high effluent quality to meet the national permit of discharge regulation. In this study, the performance and microbial community analysis were investigated in two MBRs. As the results, the performance of organic removal, nitrogen removal, and phosphorus removal was similar both MBRs. Microbial community analysis, however, showed that Azonexus sp. and Propionivibrio sp. contributed to indirect fouling to cause the chemical cleaning in the DX MBR.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.141-144
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• 2003

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.289-294
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• 2002

Cellulose production by Acetobacter pasteurianus was investigated in static culture using four bioreactors with silicone rubber membrane submerged in the medium. The shape of the membrane was flat sheet, flat sack, tube and cylindrical balloon. Production rate of cellulose as well as its yield on consumed glucose by the bacteria grown on the flat type membranes was approximately ten-fold greater than those on the non-flat ones in spite of the same membrane thickness. The membrane reactor using flat sacks of silicone rubber membrane as support of bacterial pellicle can supply greater ratio of surface to volume than a conventional liquid surface culture and is promising for industrial production of bacterial cellulose in large scale.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.2
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• pp.195-201
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• 2007

A submerged flat-sheet membrane separation system integrated with PAC (powdered activated carbon) was used in this research in order to investigate the effects of PAC on the efficiencies of operation and treatment and to evaluate the performance of the system. The experiments were carried out under operating conditions of a filtration rate of 0.38 m/d, water temperature of $20-28^{\circ}C$, and PAC dose of 0 g/L (Run-A) and 20 g/L (Run-B). The influent concentrations of TOC (total organic carbon), $NH_4{^+}-N$ (ammonia nitrogen) and $UV_{254}$ (UV absorbance at 254 nm) were 2.48 mg/L, 1.4 mg/L and 2.53 1/m, respectively. TOC removal of 43.2 and 73.6%, ammonia nitrogen removal of 4.9 and 15.9%, and $UV_{254}$ removal of 20.6 and 31.6% were obtained for Run-A and Run-B, respectively. During an experimental period of 33 days, no change was found in TMP (Run-B), but the TMP in Run-A increased by 5 kPa after 29 days. This research showed that the filtrate quality and the performance efficiency were enhanced when PAC was introduced into the filtration system.

• Membrane and Water Treatment
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• v.12 no.2
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• pp.59-64
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• 2021

The rejection of sodium chloride (NaCl) and calcium chloride (CaCl2) single salt solutions were carried out for commercial nanofiltration NFDK membrane. Results showed that the NFDK membrane had a negative surface charge and had a higher observed rejection of 93.65% for calcium (Ca2+) ion and 78.27% for sodium (Na+) ions. Prediction of rejection for aqueous solutions of both salts was made using Donnan Steric Pore Model based on Extended Nernst-Planck Equation in addition to concentration polarization film theory. A MATLAB program was developed to execute the model calculations. Absolute Average Relative Error (% AARE) was found below 5% for real rejection of the NFDK membrane. This research could be used successfully to assess the membrane characterization parameter using a proposed procedure which can reduce the number of experiments.

• Membrane Journal
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• v.15 no.3
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• pp.241-246
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• 2005

This study is investigated for the applications of MBR SYSTEM using $ENVIS^{(R)}$ which is a submerged flat membrane for treatment of sewage and wast water. The experiment was practiced on the scene of labor that are sewage facilities of factories $(10\;m^3/day)$ and wast water treatment plant $(30\;m^3/day)$ using equipments made by Pure-Envitech Co., LTD. SS, BOD and COD for the result of removal efficiency at the sewage facilities of factories were $99.7\%,\;97.6\%$, and $96.8\%$, rspectively. SS, BOD and COD for the result of removal efficiency at the waste water treatment plant were $99.6\%,\;95.6\%,\;and\;80.3\%$, respectively.

• Membrane Journal
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• v.22 no.2
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• pp.128-134
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• 2012

In this study, hydroxy polyimide (HPI) was prepared for non-porous membrane by solvent evaporation method. As the result of gas permeance properties measurement, $CO_2$ permeability was 85 Barrer and the $CO_2/N_2$ selectivity was 23 at $30^{\circ}C$. Flat sheet membrane and hollow fiber membrane were prepared by using ternary system of polymer, solvent and non-solvent additive. Morphologies and gas permeance properties were measured by FE-SEM and bubble flow meter. Each $CO_2$ permeability of 18.28 GPU, 70 GPU and $CO_2/N_2$ selectivity of 6.72, 8.63 at $30^{\circ}C$ in the flat sheet membrane and hollow fiber membrane. Hollow fiber membrane has gas permeance property better than flat sheet membrane.

• Membrane Journal
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• v.22 no.4
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• pp.258-264
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• 2012

In this study, to research effect of coagulation bath and composition of dope solution, polysulfone flat sheet membrane was fabricated by phase inversion method. PEG and PVP were used as additive. Concentration of polymer and additive, composition of coagulation bath was controlled to prepare flat sheet membrane. And then the morphology and water flux of prepared membrane were measured by FE-SEM and water flux testing apparatus. The highest value of water flux was measured at the membrane prepared under a 15 wt% PSF, 25 wt% PEG conditions, and water as coagulation bath. The pure water flux of the membrane composed of PSf/PEG was drastically decreased with increasing amount of DMAc. We confirmed that change of amount in additive and composition in coagulation bath influence the morphology and water flux performance of the membrane.

• Membrane Journal
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• v.34 no.1
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• pp.79-86
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• 2024

The flat sheet membrane, one of the representative forms of polymeric membranes, is widely used from material research in laboratories to commercial membrane production due to its ease of fabrication. Porous polymeric flat sheet membranes used in microfiltration and ultrafiltration are mainly fabricated through phase separation processes, utilizing non-solvent-induced and vapor-induced phase separation methods. However, due to the nature of phase separation processes, variations between samples can easily occur depending on the surrounding environment and the experimenter, making it difficult to ensure reproducibility. Therefore, for scaling up and ensuring reproducibility of developed membrane fabrication technologies, there is a need for a controlled environment continuous large-area production device, such as a roll-to-roll manufacturing system. This research compared the changes in membrane characteristics due to differences in manufacturing environments when scaling up laboratory-scale fabrication technologies to roll-to-roll processes using knife and slot die coaters. By optimizing the continuous manufacturing process factors, uniformity of the membrane was ensured during large-area production.