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>

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.

Vapour permeation of VOC emitted from petroleum activities: Application for low concentrations

G. Rebollar-Perez,N. Lesage,P. Moulin,E. Carretier 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

This study deals with the application of vapour permeation on the abatement of air polluted with VOC,from low to medium concentrations. Toluene, butadiene and propylene were chosen as model compounds. On a first part of the study, the permeation of single VOC, binary and ternary VOC/air mixtures was performed at different flow rates and VOC concentrations. The permeate flux, permeance,enrichment factor, separation efficiency and the recovery were determined. The experimental results were compared to those obtained with a mathematical model, allowing the calculation of the membrane area required to eliminate 95% of the feed VOC content.

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.

A review on anaerobic membrane bioreactors (AnMBRs) focused on modelling and control aspects

Robles, Á,ngel,Ruano, Maria Victoria,Charfi, Amine,Lesage, Geoffroy,Heran, Marc,Harmand, Jé,rô,me,Seco, Aurora,Steyer, Jean-Philippe,Batstone, Damien J.,Kim, Jeonghwan,Ferrer, Jos&eac Elsevier 2018 Bioresource technology Vol.270 No.-

<P><B>Abstract</B></P> <P>The use of anaerobic membrane bioreactor technology (AnMBR) is rapidly expanding. However, depending on the application, AnMBR design and operation is not fully mature, and needs further research to optimize process efficiency and enhance applicability. This paper reviews state-of-the-art of AnMBR focusing on modelling and control aspects. Quantitative environmental and economic evaluation has demonstrated substantial advantages in application of AnMBR to domestic wastewater treatment, but detailed modelling is less mature. While anaerobic process modelling is generally mature, more work is needed on integrated models which include coupling between membrane performance (including fouling) and the biological process. This should include microbial factors, which are important to generation of specific foulants such as soluble and particulate inert organics. Mature and well-established control tools, including better feedback control strategies are also required for both the process, and for fouling control.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AnMBR needs further research to optimize process efficiency. </LI> <LI> Modelling can provide insight into the factors playing a key role in AnMBR. </LI> <LI> Process models still face a long path to adaptation in practice. </LI> <LI> Better understanding of fouling mechanisms in AnMBRs is required. </LI> <LI> Control strategies can be further optimized from mechanistic knowledge of fouling. </LI> </UL> </P>

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>

Mixing and matching TREK/TRAAK subunits generate heterodimeric K_2P channels with unique properties

Blin, Sandy,Ben Soussia, Ismail,Kim, Eun-Jin,Brau, Fré,dé,é,ric,Kang, Dawon,Lesage, Florian,Bichet, Delphine National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.15

<P>The tandem of pore domain in a weak inwardly rectifying K+ channel (Twik)-related acid-arachidonic activated K+ channel (TRAAK) and Twik-related K+ channels (TREK) 1 and TREK2 are active as homodimers gated by stretch, fatty acids, pH, and G protein-coupled receptors. These two-pore domain potassium (K-2P) channels are broadly expressed in the nervous system where they control excitability. TREK/TRAAK KO mice display altered phenotypes related to nociception, neuroprotection afforded by polyunsaturated fatty acids, learning and memory, mood control, and sensitivity to general anesthetics. These channels have emerged as promising targets for the development of new classes of anesthetics, analgesics, antidepressants, neuroprotective agents, and drugs against addiction. Here, we show that the TREK1, TREK2, and TRAAK subunits assemble and form active heterodimeric channels with electrophysiological, regulatory, and pharmacological properties different from those of homodimeric channels. Heteromerization occurs between all TREK variants produced by alternative splicing and alternative translation initiation. These results unveil a previously unexpected diversity of K-2P channels that will be challenging to analyze in vivo, but which opens new perspectives for the development of clinically relevant drugs.</P>

Frequency and risk factors of severe postoperative bleeding after proctological surgery: a retrospective case-control study

Taieb Sarah,Atienza Patrick,Zeitoun Jean-David,Taouk Milad,Bourguignon Josée,Thomas Christian,Rabahi Nabila,Dahlouk Saliha,Lesage Anne-Carole,Lobo David,Etienney Isabelle 대한대장항문학회 2022 Annals of Coloproctolgy Vol.38 No.5

Purpose: The aim of this study was to assess frequency and risk factors of severe bleeding after proctological surgery requiring hemostatic surgery observed after publication of the French guidelines for anticoagulant and platelet-inhibitor treatment. Methods: All patients who underwent proctological surgery between January 2012 and March 2017 in a referral center were included. Delay, severity of bleeding, and need for blood transfusion were recorded. Patients with severe postoperative bleeding were matched to controls at a 2:1 ratio adjusted on the operator, and the type of surgery. Results: Among the 8,890 operated patients, 65 (0.7%) needed a postoperative hemostatic procedure in an operating room. The risk of a hemostatic surgery was significantly increased after hemorrhoidal surgery compared with other procedures (1.9% vs. 0.5%, P<10–4) and was most frequent after Milligan-Morgan hemorrhoidectomy (2.5%). Mean bleeding time was 6.2 days and no bleeding occurred after day 15. Blood transfusion rate was 0.1%. Treatment with anticoagulants and platelet inhibitors were managed according to recommendations and did not increase the severity of bleeding. The risk of severe bleeding was significantly lower in active smokers vs. non-smokers in univariate (16.9% vs. 36.2%, P=0.007) and multivariate (odds ratio, 0.31; 95% confidence interval, 0.14–0.65) analysis whereas sex, age, and body mass were not significantly associated with bleeding. Conclusion: Severe postoperative bleeding occurs in 0.7% of patients, but varies with type of procedure and is not affected by anticoagulant or antiplatelet treatment. These treatments given in accordance with the new guidelines do not increase the severity of postoperative bleeding.

Antagonistic Effect of a Cytoplasmic Domain on the Basal Activity of Polymodal Potassium Channels

Soussia, Ismail Ben,Choveau, Frank S.,Blin, Sandy,Kim, Eun-Jin,Feliciangeli, Sylvain,Chatelain, Franck C.,Kang, Dawon,Bichet, Delphine,Lesage, Florian Frontiers Media S.A. 2018 Frontiers in molecular neuroscience Vol.11 No.-

<P>TREK/TRAAK channels are polymodal K<SUP>+</SUP> channels that convert very diverse stimuli, including bioactive lipids, mechanical stretch and temperature, into electrical signals. The nature of the structural changes that regulate their activity remains an open question. Here, we show that a cytoplasmic domain (the proximal C-ter domain, pCt) exerts antagonistic effects in TREK1 and TRAAK. In basal conditions, pCt favors activity in TREK1 whereas it impairs TRAAK activity. Using the conformation-dependent binding of fluoxetine, we show that TREK1 and TRAAK conformations at rest are different, and under the influence of pCt. Finally, we show that depleting PIP<SUB>2</SUB> in live cells has a more pronounced inhibitory effect on TREK1 than on TRAAK. This differential regulation of TREK1 and TRAAK is related to a previously unrecognized PIP<SUB>2</SUB>-binding site (R329, R330, and R331) present within TREK1 pCt, but not in TRAAK pCt. Collectively, these new data point out pCt as a major regulatory domain of these channels and suggest that the binding of PIP<SUB>2</SUB> to the pCt of TREK1 results in the stabilization of the conductive conformation in basal conditions.</P>