• Title/Summary/Keyword: Membrane fouling

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A Study on Membrane Fouling Contaminants and Control in Enhanced Sewage Treatment by Submerged Membrane Bioreactor (침지형 분리막을 이용한 오수고도처리 공정의 막오염 원인물질 및 제어에 관한 연구)

  • Park, Chul-Hwi;Yun, Jae-Gon
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.5
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    • pp.619-627
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    • 2004
  • Purposes of this study were to examine closely the extracellular polymeric substances (EPS) which was a membrane fouling contaminant, to control detected EPS by powdered activated carbon (PAC) dosage etc. and to evaluate the possibility of practical reuse facility. With high removal efficiency of general pollutants, when the PAC is added to MBR, improvement of removal efficiency of $COD_{cr}$, and color was expected and treated wastewater can be reused. It was judged that the correlation between EPS and membrane fouling was very high. Carbohydrate and DNA in the EPS were judged to be cause of membrane fouling. If EPS could be controled, not only membrane fouling would be decreased but also operation time would be extended. In experiment of powdered activated carbon (PAC), characteristics of the best PAC for membrane fouling control were the particle size of $7{\mu}m$, lodine Number of 1,050, surface area of peat of $1,150m^2/g$. In lab test, operation time of MBR by PAC dosage of 200mg/gVSS was longer than one of MBR by without PAC dosage. Because EPS, especially carbohydrate and DNA, was controled successfully by PAC, membrane fouling in MBR could be decreased.

Prediction of Membrane Fouling Index by Using Happel Cell Model (Happel Cell 모델을 이용한 막오염 지수 예측)

  • Park, Chanhyuk;Kim, Hana;Hong, Seungkwan
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.5
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    • pp.632-638
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    • 2005
  • Membrane fouling index such as Silt Density Index (SDI) and Modified Fouling Index (MFI) is an important parameter in design of the integrated RO/NF membrane processes for drinking water treatment. In this study, the effect of particle, membrane and feed water characteristics on membrane fouling index were investigated systematically. Higher fouling index values were observed when filtering suspensions with smaller particle size and higher feed particle concentration. Larger membrane resistance due to smaller pore size resulted in an increased membrane fouling index. The variations of feed water hardness and TDS concentrations did not show any impact on fouling index, suggesting that there were no significant colloidal interactions among particles and thus the porosity of particle cake layer accumulated on the membrane surface could be assumed to be 0.36 according to random packing density. Based on the experimental observations, fundamental membrane fouling index model was developed using Happel Cell. The effect of primary model parameters including particle size ($a_p$), particle concentration ($C_o$), membrane resistance ($R_m$), were accurately assessed without any fitting parameters, and the prediction of membrane fouling index such as MFI exhibited very good agreement with the experimental results.

Utilization of aerobic granulation to mitigate membrane fouling in MBRs

  • Iorhemen, Oliver T.;Hamza, Rania A.;Tay, Joo Hwa
    • Membrane and Water Treatment
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    • v.8 no.5
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    • pp.395-409
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    • 2017
  • Membrane bioreactor (MBR) is a compact and efficient wastewater treatment and reclamation technology; but, it is limited by membrane fouling. The control of membrane fouling significantly increases operational and maintenance costs. Bacteria and their byproducts - extracellular polymeric substances (EPS) - are major contributors to membrane fouling in MBRs. A recent attempt at fouling mitigation is the development of aerobic granular sludge membrane bioreactor (AGMBR) through the integration of a novel biotechnology - aerobic granulation - and MBR. This paper provides an overview on the development of AGMBR to mitigate membrane fouling caused by bacteria and EPS. In AGMBR, EPS are used up in granule formation; and, the rigid structure of granules provides a surface for bacteria to attach to rather than the membrane surface. Preliminary research on AGMBR using synthetic wastewater show remarkable membrane fouling reduction compared to conventional MBR, thus improved membrane filtration. Enhanced performance in AGMBR using actual municipal wastewater at pilot-scale has also been reported. Therefore, further research is needed to determine AGMBR optimal operational conditions to enhance granule stability in long-term operations and in full-scale applications.

Effect of Membrane Fouling due to Micro-organism Growth on the Membrane Surface (막면 세균 증식에 의한 막오염에 관한 연구)

  • Kim, Hyung Soo
    • Journal of Korean Society of Water and Wastewater
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    • v.13 no.3
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    • pp.36-41
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    • 1999
  • High quality drinking water can be produced by membrane separation process. A major problem in the current system is a membrane fouling control. In order to investigate membrane fouling due to E.coll removal, lab scale experiment using MF and UF and semi pilot plant experiment using UV radiation or not was performed. AS a result, the possibility of membrane fouling control by repressing of micro-organism on the membrane surface was clearly verified. But it was not clearly verified in this experiment the combined effect with other factors such as Turbidity, organic and inorganic matters.

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Membrane fouling in thermophilic membrane bioreactor with different sludge retention times

  • Ince, Elif;Ince, Mahir;Topaloglu, Alikemal
    • Membrane and Water Treatment
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    • v.9 no.5
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    • pp.343-351
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    • 2018
  • As membrane fouling is based on various factors, it is a complex phenomenon that is hard to estimate. This study investigated membrane fouling in a thermophilic jet loop membrane bioreactor (JLMBR). With this purpose, four different empirical membrane fouling models with different sludge retention times were applied on the flow data obtained in the system. As a result of the model implementation, it was found for all sludge retention times that, standard blocking is effective in the first 1.5 hours of filtration, while cake filtration was dominant in the remaining duration. Additionally, it was observed that as the sludge retention time increases, membrane fouling rate decreases.

Effect of Ozonation in Microfiltration Membrane for Wastewater Reuse (정밀여과법 하수재이용 공정에서 오존의 전처리 효과에 관한 연구)

  • Moon, Seong-Yong;Ahn, Se-Hyuk;Lee, Sang-Hyup;Park, Jong-Hoon;Hong, Suk-Won;Choi, Yong-Su
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.535-543
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    • 2006
  • The Ozone oxidation process was applied to increase the efficiency of reuse process when treating the secondary effluent by the membrane system. This paper focus on decreasing efficiency of membrane fouling, because of membrane fouling reduction by ozone and evaluation of application of the ozone oxidation. The feed water was secondary effluent from BNR process. The result shows that the ozone pretreatment can reduce membrane fouling effectively. Also, the improvement of treated water quality was obvious. The reduction of the membrane fouling led decrease of following pollutant and increase of lnner adsorptive ability of hydrophilic organic matter and decrease of molecular weight. MF membrane process alone can meet the domestic reuse water standards. And ozone pretreatment process also can increase the removal rates of turbidity, COD, nitrogen, and color.

A Study on Membrane Fouling by Flux and Linear Velocity in Coagulation/Ultrafiltration Membrane System (응집·한외여과 조합공정에서 플럭스와 선속도가 막오염에 미치는 영향에 관한 연구)

  • Moon, Seong-Yong;Lee, Sang-Hyup;Kim, Seung-Hyun;Yoon, Cho-Hee
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.4
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    • pp.429-436
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    • 2005
  • A coagulation/ultrafiltration membrane hybrid system was operated to treat river water with capacity of $0.06m^3/d$. The impact on membrane fouling by flux and linear velocity was investigated. It is known that pressure increase is proportional to flux increase. However, pressure increase was much faster than theoretical value in the pilot plant test. So it was suggested that flux was on important factor in ultrafiltration of continuous operation. Membrane fouling was decreased when linear velocity was increased. This phenomenon was found more obviously without coagulation. With the combination of coagulation and sedimentation, membrane fouling was not reduced conspicuously. Big particles formed during coagulation and sedimentation were destroyed by feed and circulation pumping, which resulted in little effect on membrane fouling reduction. The degree of destruction was similar at various linear velocities. In this study, the hollow fiber membrane was used and the system was operated in pressure type module. In case of the system used in this study, membrane fouling has been affected lightly by linear velocity variation when coagulation pretreatment was applied.

A study on the treatment of water discharge from the water treatment plant using end-free submerged membrane - Causes and solution of membrane fouling - (자유 말단형 침지식 분리막을 이용한 정수장 배출수 처리 연구 - 막오염 발생 원인과 해결 방안 -)

  • Kim, Jun-Hyun;Jang, Jung-Woo;Kim, Jin-Ho;Park, Kwang-Duck
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.2
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    • pp.93-104
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    • 2020
  • As water resources are limited and legal regulations are strengthened, there is a growing need to reuse residuals in WTP(Water Treatment Plant). In this study, membrane filtration system was constructed and its operation method was studied for water quality stabilization and reuse of WTP residuals. The operation parameters were stable for 1 year and 6 months. Membrane fouling was identified as particulate pollution (activated carbon) and inorganic pollution (manganese). The membrane system was operated steadily with raw water of high concentration SS(Suspended solid) containing activated carbon because membrane fouling was reduced by the effect of End-Free type. In the case of inorganic contamination, dissolved manganese eluted by chemicals and acted as a membrane fouling source, and the operating conditions for minimizing membrane fouling. were confirmed by newly developing application methods and types of cleaning chemicals. Based on the results, design parameters for reducing manganese membrane fouling were derived.

Prevention of membrane fouling by roughing filter for the stand-alone MD process (해수담수화 막 증류 공정에서 유입수 전처리 적용에 따른 막 오염 평가)

  • Yun, Taekgeun;Jeong, Seongpil;Kim, Hyewon;Hong, Seungkwan;Lee, Seockheon
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.4
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    • pp.301-307
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    • 2018
  • Membrane distillation (MD) is a thermally driven desalination process with a hydrophobic membrane. MD process has been known to have a lower fouling potential compared to other pressure-based membrane desalination process (NF, RO). However, membrane fouling also occurs in MD process. In this study, the membrane fouling was observed in MD process according to the pre-treatment processes. The filtration and precipitation processes were applied as the pre-treatment to prevent the membrane fouling. The pore sizes of roughing filters were 0.4, 5, 10, 30, and $60{\mu}m$. The concentration of the coagulant was 1.2 mg/L as $FeCl_3$. The membrane fouling on MD membrane was successfully removed with both pre-treatment processes.

Effect of solids retention time on membrane fouling in membrane bioreactors at a constant mixed liquor suspended solids concentration

  • Hao, L.;Liss, S.N.;Liao, B.Q.
    • Membrane and Water Treatment
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    • v.8 no.4
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    • pp.337-353
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    • 2017
  • Membrane fouling at different solids retention times (SRT) (7, 12 and 20 days) was studied under well-controlled conditions in a laboratory-scale aerobic submerged membrane bioreactor under constant biomass concentration using a synthetic high strength wastewater. An increase in SRT was found to improve membrane performance and this correlated to changes in the total production of bound extracellular polymeric substances (EPS), and the composition and properties of bound EPS using X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectroscopy (FTIR) and floc sizes. A larger amount of total bound EPS was found at the lowest SRT (7 days) tested but the ratio of proteins (PN) to carbohydrates (CH) in bound EPS increased with an increase in SRT. Similarly, the quantity of soluble microbial products (SMP) decreased with an increase in SRT and the SMP PN/CH ratio increased with an increase in SRT. SMP concentrations positively correlated to the percentage of membrane pore blocking resistance. The quantity of total bound EPS and total SMP positively corresponded to the membrane fouling rate, while the PN/CH ratio in the bound EPS and SMP negatively correlated to the membrane fouling rate. The results show that both the quantity and composition of bound EPS and SMP and floc sizes are important in controlling membrane fouling.