• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.27-34
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• 2006

This study was conducted to evaluate the performance of a membrane bioreactor filled with high concentration of powdered activated carbon (HCPAC-MBR) to reduce DBPs at the drinking water treatment. The pilot system was installed after the rapid sand filtration process whose plant was the conventional treatment process. The removal efficiencies of DBPs were measured during pilot operation period of 2 years. HAA and THM removal rates could be maintained around 80~90% without any troubles and then tremendous reduction of HAA and THM reactivity were observed more than 52%. The average removal rate of HAA formation potential (FP) and THM formation potential (FP) were 70.5% and 67.6% respectively. It is clear that the PAC membrane bioreactor is highly applicable for advanced water treatment to control DBPs.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.365-369
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• 2004

Submerged membrane bio-reactor equipped with a hollow fiber microfiltration was applied to reuse weaving wastewater of water jet loom, where two parameters such as the concentration of MLSS and the flux were controlled. While the flux at the concentration of MLSS around 900mg/L was constantly kept over 0.4m/d and 0.8m/d in a short time, the stable flux at around 300mg/L of MLSS was shown at the 8 days later. Regardless of MLSS and flux, BOD, CODcr and Turbidity of the permeate were 1~2mg/L, 7~10mg/L and below 1 NTU, which were 85~90%, 87~90% and 98% of removal efficiency, respectively. The stable operation without fouling was achieved because the contents of ECP were smaller than those of common MBR processes and the composition(saccharide/protein) was kept constantly. In this study, 0.5~1.0m/d of flux and 400~900mg/L of MLSS were considered as the most recommendable operating condition for the reuse of weaving wastewater.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.945-949
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• 2006

For a membrane bio-reactor, it is possible to fillet and separate activated sludge and effluent by head loss of centimeters, if non-woven fabric material is used as titration media. However, if non-woven fabric material is used to thicken high-concentration sludge, excessive sludge attachment causes the rapid decrease of flux. Mesh with fore sizes of $100{\mu}m,\;150{\mu}m,\;and\;200{\mu}m$ allows for easy separation of attached sludge. This study examined the possibility of mesh as filtration media. Existing close-flow filtration process, which requires maintaining sludge movement, makes It difficult to obtain high thickening rate. With a view of complementing this weakness, this study has made an experimental examination on how high-concentration sludge (about 3,000mg/L to 10,000mg/L) will be filtered and thickened when mesh module is submersed in the bio-reactor. Effluent flowed from the bottom of the bio-reactor by head loss of 65cm. In case of pore size of $100{\mu}m$, SS showed high recovery of 80% to 96%; therefore, it has been decided that mesh can be used as filtration media. Filtration lasted for more than 9 hours, until sludge with 9,000mg/L in MLSS concentration was thickened 9 times as dense. In the range from 3,610mg/L to 9,060mg/L in MLSS concentration, it was possible to obtain effluent with less than 2mg/L in MLSS concentration within 10 minutes.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.724-729
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• 2013

Simultaneous nitrification and denitrification (SND) occurs concurrently in the same reactor under micro dissolved oxygen (DO) conditions. Anaerobic zone was applied for phosphorus release prior to an aerated membrane bio-reactor (MBR), and anoxic zone was installed by placing a baffle in the MBR for enhancing denitrification even in high DO concentration in the MBR. Phosphorus removal was tested by alum coagulation in the anaerobic reactor preceding to MBR. DO concentration were 2.0, 1.5, 1.0, 0.75 mg/L in the MBR at different operating stages for finding optimum DO concentration in MBR for nitrogen removal by SND. pH was maintained at 7.0~8.0 without addition of alkaline solution even with alum addition due to high alkalinity in the raw sewage. Both TCODcr and $NH_4^+$-N removal efficiency were over 90% at all DO concentration. TN removal efficiencies were 50, 51, 54, 66% at DO concentration of 2.0, 1.5, 1.0, 0.75 mg/L, respectively. At DO concentration of 0.75 mg/L with addition of alum, TN removal efficiency decreased to 54%. TP removal efficiency increased from 29% to 95% by adding alum to anaerobic reactor. The period of chemical backwashing of the membrane module increased from 15~20 days to 40~50 days after addition of alum.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.321-328
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• 2017

Recently EC-MBR (Elctrocoagulation - Membrane Bio Reactor) has been suggested as one of alternative processes to overcome membrane fouling problems. Most important operational parameters in the EC-MBR are known to current density and contact time. Their effect on membrane filtration performances has been reported well, however, quantitative interrelationship between both parameters not been investigated yet. The purpose of this study is to give a kinetic model suggesting the current density and the contact time required to reduce the membrane fouling. The 4 different set of current densities (2.5, 6, 12 and $24A/m^2$) and contact times (0, 2, 6 and 12 hr) were selected as operational parameters. After each electro-coagulation under the 16 different conditions, a series of membrane filtration was carried out. The membrane fouling decreased as the current density and contact time increased, Total fouling resistances under different conditions, $R_t(=R_c+R_f)$ were calculated and compared to those of the controls ($R_0$), which were calculated from the data of experiments without electro-coagulation. A kinetic approach for the fouling reduction rate ($R_t/R_0$) was carried out and the equation ${\rho}^{0.46}_it=7.0$ was obtained, which means that the product of current density and the contact time needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.269-276
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• 2012

The surface characteristics and performance of PTFE (polytetrafluoroethylene) hollow fiber membranes have been systematically investigated at lab- and pilot-scale to assess their application to membrane-bioreactor, particularly for integrating wastewater reclamation and rainwater harvesting. The PTFE membrane expressed some surface features, such as hydrophobicity, which might enhance membrane fouling. However, lab-scale performance and cleaning experiments under various conditions demonstrated that the PTFE membrane could produce the desirable water flux with good cleaning efficiency, implying easy operation and maintenance due to superior chemical resistance of PTFE membranes. Most of effluent water qualities were met with Korean standard for discharge and reuse, except color. Color level was further reduced by blending with rainwater at 75:25 ratio. Based on the lab-scale experimental results, the pilot plant was designed and operated. Pilot operation clearly showed sTable performance with satisfactory water quality, suggesting that PTFE membrane could be applied for decentralized MBR integrated with rainwater use.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.3
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• pp.5-16
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• 2021

In this study, the applicability of the MBR(Membrane Bio Reactor) process of oxygen dissolve was evaluated through comparison and evaluation of the efficiency of oxygen dissolve device and conventional aeration device in the explosive tank within the MBR process. The organic matter and ammonia oxidation by oxygen dissolve device were evaluated, and the efficiency of persaturation was evaluated by applying real waste water (anaerobic digester effluent treatement from food waste). SCOD and ammonia removal rates for oxygen dissolve device and conventional aeration device methods were similar. However, it was determined that the excess sludge treatment cost could be reduced as the yield of microorganisms by oxygen dissolve device is about 0.03 g MLSS-produced/g SCOD-removed lower than that of microorganisms by conventional aeration device. The removal rates of high concentrations of organic matter (4,000 mg/L) and ammonia (1,400 mg/L) in anaerobic digester effluent treatment from food waste were compared to the conventional aeration device and the oxygen dissolve device organic matter removal rate was approximately 13% higher than that of the conventional aeration device. In addition, for MLSS, the conventional aeration device was 0.3 times higher than for oxygen dissolve device. This is believed to be due to the high progress of sludge autooxidation because the dissolved oxygen is sufficiently maintained and supplied in the explosive tank for oxygen dissolve device. Therefore, it was determined that the use of oxygen dissolve device will be more economical than conventional aeration device as a way to treat wastewater containing high concentrations of organic matter.

• Environmental Engineering Research
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• v.11 no.2
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• pp.91-98
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• 2006

There is a possibility of the production of the air bubbles in membrane pores due to the reduction in pressure during membrane filtration. The effect of fine air bubbles from dissolved gases on microfiltration was investigated in the submerged membrane bio-reactor (SMBR). The $R_{air}$ (air bubble resistance) was defined as the filtration resistance due to the air bubbles formed from the gasification of dissolved gases. From the results of filtration tests using pure water with changes in the dissolved oxygen concentration, the air bubbles from dissolved gases were confirmed to act as a foulant and; thus, increase the filtration resistance. The standard pore blocking and cake filtration models, SPBM and CFM, respectively, were applied to investigate the mechanism of air bubble fouling on a hollow fiber membrane. However, the application of the SPBM and CFM were limited in explaining the mechanism due to the properties of air bubble. With a simple comparison of the different filtration resistances, the $R_{air}$ portion was below 1% of the total filtration resistance during sludge filtration. Therefore, the air bubbles from dissolved gases would only be a minor foulant in the SMBR. However, under the conditions of a high gasification rate from dissolved gases, the effect of air bubble fouling should be considered in microfiltration.

• Environmental Engineering Research
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• v.12 no.4
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• pp.157-175
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• 2007

The membrane biofilm reactor (MBfR) creates a natural partnership of a membrane and biofilm, because a gas-transfer membrane delivers a gaseous substrate to the biofilm that grows on the membrane's outer wall. $O_2$-based MBfRs (called membrane aerated biofilm reactors, or MABRs) have existed for much longer than $H_2$-based MBfRs, but the $O_2$-based MBfR is a versatile platform for reducing oxidized contaminants in many water-treatment settings: drinking water, ground water, wastewater, and agricultural drainage. Extensive bench-scale experimentation has proven that the $H_2$-based MBfR can reduce many oxidized contaminant to harmless or easily removed forms: e.g., ${NO_3}^-$ to $N_2$, ${ClO_4}^-$ to $H_2O$ and $Cl^-$, ${SeO_4}^{2-}$ to $Se^0$, and trichloroethene (TCE) to ethene and $Cl^-$. The MBfR has been tested at the pilot scale for ${NO_3}^-$ and ${ClO_4}^-$ and is now entering field-testing for many of the oxidized contaminants alone or in mixtures. For the MBfR to attain its full promise, several issues must be addressed by bench and field research: understanding interactions with mixtures of oxidized contaminants, treating waters with a high TDS concentration, developing modules that can be used in situ to augment pre-denitrification of wastewater, and keeping the capital costs low.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.42-49
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• 2017

The application of electro-coagulation has been attempted to control the membrane fouling problem in a MBR (Membrane Bio-Reactor). This study examined the effects of the operating parameters (current density and contact time) of the electro-coagulation process on the change in the characteristics of activated sludge. The current density changed from 2.5 to 12, $24A/m^2$, and the contact time was varied from 0 to 2 and 6 hr, respectively. At a current density of $24A/m^2$ and 6 hr of operation, the MLSS changed from 6,800 to 7,000 mg/L (3% increase), but the MLVSS did not increase significantly. After 6 hr of operation, the soluble COD decreased from 71 to 37 mg/L under the $24A/m^2$ condition, from 113 to 67 mg/L under the $12A/m^2$ condition, and from 84 to 80 mg/L under the $2.5A/m^2$ condition. On the other hand, soluble-TN and -TP concentration showed slight changes. The soluble-EPS and Bound-EPS concentration decreased slightly with increasing current density. The membrane filtration performance of activated sludge before and after electro-coagulation was compared. The filtration resistances after electro-coagulation decreased from 6 to 61 %, particularly as the current density and contact time were increased. This indicates that electro-coagulation can be used to control membrane fouling in the MBR process.