• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.44-53
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• 2011

Membrane bio-reactor (MBR) has several advantages over the conventional activated sludge process, including a high biomass, low sludge production, and better permeate quality. Therefore, the MBR have gained popularity for municipal and industrial wastewater treatment. However the MBR usually were used for sewage and low streng th wastewater treatment because of membrane fouling problem and limitation of oxygen transfer into biomass. In this study, the hybrid process combining MBR and pure oxygen was tested for high strength organic wastewater treatment in the COD loading range from 2 to $10kgCOD/m^3{\cdot}day$. The hybrid process, membrane coupled pure oxygen high compact reactor (MPHCR), had been operated for one year and operation parameters, the effect of COD loading, MLSS concentration and the location of membrane module were studied for membrane fouling characteristic. Also membrane resistance test and the component of foulant was analyzed to investigate what is specific foulant in the MBR.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.183-190
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• 2020

Although membrane bio-reactor (MBR) has been widely applied for wastewater treatment plants, the membrane fouling problems are still considered as an obstacle to overcome. Thus, many studies and commercial developments on mitigating membrane fouling in MBR have been carried out. Recently, high voltage impulse (HVI) has gained attention for a possible alternative technique for desalting, non-thermal sterilization, bromate-free disinfection and mitigation of membrane fouling. In this study, it was verified if the HVI could be used for mitigation of membrane fouling, particularly the internal pore fouling in MBR. The HVI was applied to the fouled membrane under different conditions of electric fields (E) and contact time (t) of HVI in order to investigate how much of internal pore fouling was reduced. The internal pore fouling resistance (R_f) after HVI induction was reduced as both E and t increased. For example, R_f decreased by 19% when the applied E was 5 kV/cm and t was 80 min. However, the R_f decreased by 71% as the E increased to 15 kV/cm under the same contact time. The correlation between E and t that needed for 20% of R_f reduction was modeled based on kinetics. The model equation, E^1.54t = 1.2 × 10³ was obtained by the membrane filtration data that were obtained with and without HVI induction. The equation states the products of En and t is always constant, which means that the required contact time can be reduced in accordance with the increase of E.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.151-154
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• 2002

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2314-2320
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• 2015

MBR (Membrane Bio-Reactor) process is known to consume enormous energy to control membrane fouling. To solve this problem, electro-coagulation technique has been applied to MBR. A series of electro-coagulation was applied to activated sludge suspension under different current density condition. After the electro-coagulations, membrane filtration of the activated sludge suspensions was conducted to investigate the effect of electro-coagulation on the fouling. As current density increased 10 to 40A/m2, the total fouling resistance (Rc+Rf) decreased from 18 to 79%, showing that the electro-coagulation improved the membrane filtration efficiency. Both the organic concentration in bulk and the particles size distribution were not nearly changed before and after the electro-coagulation. The enhanced filtration efficiency might be due to the aluminum hydroxide generated from chemical precipitation, which can be acted as a dynamic membrane preventing a deposition of foulants on membrane surfaces.

• 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.

• Korean Membrane Journal
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• v.3 no.1
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• pp.1-8
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• 2001

A lab-scale submerged membrane bio-reactor (MBR) with intermittent aeration was carried out for investigating the behavior of soluble microbial products (SMP). The SMP concentration of mixed liquor at Run 1 accumulated immediately at the end of running and biodegradable SMP converted into non-biodegradable SMP, but it did not occurred at the Run 2 and 3. The SMP formation coefficient (k) at the anoxic phase was a little higher than oxic phase, and the lowest k was investigated at Run 3. The combination of biological denitrification with the MBR Process was advantageous in the prevention of membrane bio-fouling.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.141-148
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• 2008

This study was conducted to evaluate the effect of PAC(Powder Activated Carbon) retention time on stable operation of high concentration powered activated carbon(HCPAC-MBR) in the treatment of secondary domestic wastewater. The pilot scale HCPAC-MBR system was operated at two different SRTs, 25 days and 100 days. The main drawback of HCPAC-MBR system was the rapid increase of trans-membrane pressure. The increase rate of trans-membrane pressure was proportional to SRT value at constant flux. This result seemed to be caused by reduced amount of EPS adsorbed on the PAC in the reactor by decreasing the SRT of the PAC. The particle size of the PAC was also influenced by SRT. The PAC size was decreased as SRT was increased. The change of particle size could be one reason for the change of trans-membrane pressure. The pore volume in the cake-layer formed on the membrane surface became to be increased by reducing SRT, because the cake-layer was highly composed of the PAC. Therefore, increased pore volume might play a role to reduce the trans-membrane pressure. The removal rate of E260 and TOC was also inversely proportional to SRT value.

• 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 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.

• 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.