Macroscopic approach to develop fouling model under GAC fluidization in anaerobic fluidized bed membrane bioreactor

Charfi, A.,Aslam, M.,Lesage, G.,Heran, M.,Kim, J. Korean Society of Industrial and Engineering Chemi 2017 Journal of industrial and engineering chemistry Vol.49 No.-

<P>A mathematical model was presented to understand membrane fouling in anaerobic fluidized bed membrane bioreactor (AFMBR). Assuming three fouling mechanisms, the cake formation, progressive porosity reduction and the pore blocking, the model describes the effect of granular activated carbon (GAC) on fouling resistance and mechanisms. The model shows satisfactory description of transmembrane pressure with R-2 approximate to 99%. Using GAC particles (2-3 mm) allows a better fouling mitigation by removing cake deposit while long term fouling is due to pore blocking. The fluidized small GAC particles (0.18-0.5 mm) foster the cake formation by their deposit on membrane surface. 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>

ON RELATIVE ESSENTIAL SPECTRA OF BLOCK OPERATOR MATRICES AND APPLICATION

Charfi, Salma,Walha, Ines Korean Mathematical Society 2016 대한수학회보 Vol.53 No.3

In this paper, we investigate relative essential spectra of $2{\times}2$ block operator matrix using the Fredholm perturbation theory. Furthermore, an example for two-group transport equations is presented to illustrate the validity of the main results.

A modelling approach to study the fouling of an anaerobic membrane bioreactor for industrial wastewater treatment

Charfi, Amine,Thongmak, Narumol,Benyahia, Boumediene,Aslam, Muhammad,Harmand, Jé,rô,me,Amar, Nihel Ben,Lesage, Geoffroy,Sridang, Porntip,Kim, Jeonghwan,Heran, Marc Elsevier 2017 Bioresource technology Vol.245 No.1

<P><B>Abstract</B></P> <P>An Anaerobic Membrane BioReactors (AnMBR) model is presented in this paper based on the combination of a simple fouling model and the Anaerobic Model 2b (AM2b) to describe biological and membrane dynamic responses in an AnMBR. In order to enhance the model calibration and validation, Trans-Membrane Pressure (TMP), Total Suspended Solid (TSS), COD, Volatile Fatty Acid (VFA) and methane production were measured. The model shows a satisfactory description of the experimental data with R<SUP>2</SUP> ≈0.9 for TMP data and R<SUP>2</SUP> ≈0.99 for biological parameters. This new model is also proposed as a numerical tool to predict the deposit mass composition of suspended solid and Soluble Microbial Products (SMP) on the membrane surface. The effect of SMP deposit on the TMP jump phenomenon is highlighted. This new approach offers interesting perspectives for fouling prediction and the on-line control of an AnMBR process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A model has been proposed to simulate fouling in an anaerobic membrane bioreactor. </LI> <LI> The proposed model is able to simulate the major foulants concentrations in the AnMBR. </LI> <LI> A numerical tool has been developed to determine the deposit cake composition. </LI> <LI> The Transmembrane pressure jump is due to a decrease in cake porosity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Particle-sparged anaerobic membrane bioreactor with fluidized polyethylene terephthalate beads for domestic wastewater treatment: Modelling approach and fouling control

Charfi, Amine,Park, Eunyoung,Aslam, Muhammad,Kim, Jeonghwan Elsevier 2018 Bioresource technology Vol.258 No.-

<P><B>Abstract</B></P> <P>The study presents a mathematical model developed to better understand and control membrane fouling in a single-staged, anaerobic fluidized bed membrane bioreactor (AFMBR) using polyethylene terephthalate (PET) beads as scouring media. The model was based on combining the anaerobic biological model AM2b and a fouling model applied in membrane filtration. The presented model was validated using experimental data obtained by a laboratory scaled AFMBR reactor run during 250 d under various operational conditions. The combined AM2b and fouling model was able to simulate volatile suspended solids, soluble COD concentration, soluble microbial products concentrations and the methane production rate at steady-state condition with R<SUP>2</SUP> of 95% as well as the trans-membrane pressure with R<SUP>2</SUP> of 99%. The model was able to predict dominant fouling mechanism by assessing fouling resistances caused by cake formation and pore blocking separately.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Model was developed to understanding fouling in anaerobic fluidized membrane bioreactor. </LI> <LI> Polyethylene terephthalate beads were applied as fluidized media to control fouling. </LI> <LI> Model was able to simulate well fouling rate, VSS, SCOD and methane production rate. </LI> <LI> Dominant fouling mechanism was assessed by cake formation and pore blockage separately. </LI> </UL> </P>

Membrane fouling by sodium alginate in high salinity conditions to simulate biofouling during seawater desalination

Charfi, Amine,Jang, Hoseok,Kim, Jeonghwan Elsevier 2017 Bioresource technology Vol.240 No.-

<P><B>Abstract</B></P> <P>This study aims to better understand biofouling by algal organic matters (AOM) during seawater pretreatment by microfiltration (MF). To simulate AOM biofouling, sodium alginate (SA) solutions with three different concentrations (2, 20 and 50ppm) were filtered in dead-end mode with MF membrane. A modelling approach with blocking laws was used to identify the fouling mechanisms behind flux decline with time. The effect of SA concentration and cations such as Na<SUP>+</SUP> (0.6M) and Ca<SUP>2+</SUP> (0.015M) addition to SA solution on fouling mechanisms was studied. While for low SA concentration (2ppm), fouling occurs within two phases: a pore constriction phase followed by cake formation phase, for high SA concentration (50ppm), fouling occurs within only one phase controlled by cake formation. The addition of Na<SUP>+</SUP> (0.6M) or Ca<SUP>2+</SUP> (0.015M) to SA solution mitigates membrane fouling, however, the addition of both cations enhances fouling by formation of dense cake layer on membrane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> During sodium alginate microfiltration, fouling mechanisms depend on SA concentration. </LI> <LI> Na<SUP>+</SUP> (0.6M) reduces membrane fouling during SA microfiltration. </LI> <LI> Ca<SUP>2+</SUP> and Na<SUP>+</SUP> together leads to quick deposit formation regardless of SA concentration. </LI> <LI> In low ionic strength conditions (0.03M) binding of SA by Ca<SUP>2+</SUP> decreases. </LI> <LI> In high ionic strength conditions (0.6M), SA is highly rejected by MF membrane. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Modelling approach to better control biofouling in fluidized bed membrane bioreactor for wastewater treatment

Charfi, Amine,Aslam, Muhammad,Kim, Jeonghwan Elsevier 2018 CHEMOSPHERE - Vol.191 No.-

<P><B>Abstract</B></P> <P>A mathematical model has been developed to better understand fouling mitigation mechanisms in particle-sparged membrane bioreactor. The model developed herein assumes two fouling mechanisms, (i) the pore blocking leading to the decrease in membrane surface porosity and (ii) the progressive development of compressible cake layer on the membrane surface. The model has been validated by comparison with <I>trans</I>-membrane pressure data registered from the bioreactor filtering a synthetic solution consisting of bentonite, sodium alginate and bovin serum albumine (BSA). Two nonporous media have been tested, Polyethylene terephthalate (PET) beads and silica particles with different dosage (0, 10, 30, 50 and 70% (v/v)). Compared to the experimental data, the model shows satisfactory fitting with R<SUP>2</SUP> ≥ 93%. For both media tested, an optimal dosage to minimize fouling rate was observed at 50% (v/v). Even if both fouling mechanisms have been mitigated by adding fluidized media, pore blocking was more pronounced than cake formation. Moreover, better pore blocking mitigation was observed with PET media (50% (v/v)) having bigger size and lower density than silica particles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Model was developed to better understand fouling in fluidized membrane bioreactor. </LI> <LI> Pore blockage models agreed well with results with different media dosage. </LI> <LI> Optimal dosage of non-adsorbing media (50% (v/v)) to minimize fouling was observed. </LI> <LI> PET media with bigger size and lower density allowed better pore blocking mitigation. </LI> </UL> </P>

Macroscopic approach to develop fouling model under GAC fluidization in anaerobic fluidized bed membrane bioreactor

Amine Charfi,Muhammad Aslam,Geoffroy Lesage,Marc Heran,김정환 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-

A mathematical model was presented to understand membrane fouling in anaerobicfluidized bedmembrane bioreactor (AFMBR). Assuming three fouling mechanisms, the cake formation, progressiveporosity reduction and the pore blocking, the model describes the effect of granular activated carbon(GAC) on fouling resistance and mechanisms. The model shows satisfactory description of transmem-brane pressure with R299%. Using GAC particles (2–3 mm) allows a better fouling mitigation byremoving cake deposit while long term fouling is due to pore blocking. Thefluidized small GAC particles(0.18–0.5 mm) foster the cake formation by their deposit on membrane surface.

막증발 공정 모델링과 유기오염물질에 의한 막오염 효과 분석

( Amine Charfi ),( Fida Tibi ),김정환 ( Jeonghwan Kim ),조진우 ( Jin-woo Cho ) 한국폐기물자원순환학회(구 한국폐기물학회) 2021 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2021 No.-

Nowadays the membrane distillation (MD) technology for wastewater treatment has been regarded with growing interest. The MD is able to separate non-volatile contaminants to obtain highly purified water. Operated at low pressure, the MD system showed less fouling risk than pressure-driven separation technologies. Nevertheless, the fouling phenomenon is still an issue which hinders the MD performance by decreasing its productivity as well as its separation effectiveness. This study aims at better understanding the organic fouling mechanisms and their effect on permeate flux decline in a direct contact membrane distillation treating synthetic wastewater. A mathematical model was developed to simulate the permeate flux variation with time. The model simulates the deposit mass of the cake layer as the difference between the matter dragged by convective forces to the membrane surface and the mass detached by the turbulence effect. The permeate flux is expressed by a resistance in series model as the ratio of the vapor pressure difference and the sum of the initial membrane resistance and the cake layer resistance. The cake layer resistance is proportional to the deposit mass and the specific cake resistance expressed by kozeny-Carman relation as proportional to the cake porosity. The model was validated using experimental flux data obtained using a synthetic solutions of sodium alginate and bovine serum albumin to simulate polysaccharides and proteins, respectively, considered as the main organic foulants, at different temperatures and pHs. The model showed a satisfactory fitting result with a coefficient of determination R2 ≥ 90%.

On relative essential spectra of block operator matrices and application

Salma Charfi,Ines Walha 대한수학회 2016 대한수학회보 Vol.53 No.3

In this paper, we investigaterelative essential spectra of $2\times2$ block operator matrix using the Fredholm perturbation theory. Furthermore, an example for two-group transport equations is presented to illustrate the validity of the main results.

Membrane bioreactors for wastewater treatment: A review of mechanical cleaning by scouring agents to control membrane fouling

Aslam, M.,Charfi, A.,Lesage, G.,Heran, M.,Kim, J. Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.307 No.-

Membrane bioreactor (MBR) is a reliable and promising technology for wastewater treatment and reclamation applications. In spite of more than a decade of significant advances in developing fouling mitigation methods, different physical and cleaning protocols are still necessary to be developed to limit the membrane fouling. The use of scouring agents in MBR applications has been paid attention as a new approach as an energy-efficient way to control membrane fouling. Recently, mechanical cleaning by scouring agents is becoming an intense research area considering high efficiency of fouling reduction while requiring low energy consumption. In this review, fundamental and comprehensive assessments of the mechanical cleaning concepts and their applications with porous and nonporous scouring agents for MBR system are critically reviewed. The existing challenges and future research prospects on the mechanical cleaning technology associated with scouring agents for the MBR applications are also discussed.