scholarly journals Mekanisme Fouling pada Membran Mikrofiltrasi Mode Aliran Searah dan Silang

2019 ◽  
Vol 13 (1) ◽  
pp. 6 ◽  
Author(s):  
Iqbal Shalahuddin ◽  
Yusuf Wibisono
Keyword(s):  
Membrane Filtration ◽  
Cross Flow ◽  
Flow Mode ◽  
Cake Filtration ◽  
Water And Wastewater Treatment ◽  
Critical Flux ◽  
Membrane Pores ◽  
Fouling Mechanism ◽  
Dead End ◽  
Microfiltration Membranes

A B S T R A C TMicrofiltration is a low pressure driven membrane process of about 1 bar trans-membrane pressure which is used frequently for separating dissolved particles within 0.1 to 10 μm size. Microfiltration membranes are utilized in water and wastewater treatment processes either during pretreatment, treatment, or post-treatment steps. Moreover in bioprocessing, microfiltration is used in upstream process for substrate sterilization or in downstream process for microbial suspension separation. Fouling is one major concern of membrane filtration processes, including microfiltration. In this article, the fouling mechanism on microfiltration membrane is explained based on the blocking model refer to cake filtration due to the complexity of fouling phenomena. Fouling mechanism on dead-end and cross-flow modes microfiltration are explained, and basically distinguished into four different mechanisms, i.e. complete blocking, standard blocking, intermediate blocking and cake filtration. The proposed models are based on constant pressure operation on the uniform membrane pores, both for dead-end and cross-flow modes. Cross-flow mode, however, is restricted on the beginning of filtration until critical flux condition is reached.Keywords: bioprocess; blocking model; cake filtration; fouling; microfiltration; wastewater A B S T R A KMembran mikrofiltrasi merupakan salah satu teknologi membran yang menggunakan tekanan rendah sekitar 1 bar sebagai gaya pendorong dan digunakan untuk proses pemisahan partikel terlarut yang berukuran antara 0,1 hingga 10 μm. Membran mikrofiltrasi banyak digunakan baik dalam proses pra-pengolahan, pengolahan, maupun pasca-pengolahan air dan air limbah. Pada bioproses, mikrofitrasi juga digunakan pada proses hulu untuk sterilisasi substrat atau pada proses hilir untuk pemisahan suspensi mikrob. Masalah yang paling utama dalam proses filtrasi membran adalah fouling. Dalam artikel ini, mekanisme terjadinya fouling pada membran mikrofiltrasi dijelaskan dengan menggunakan model pemblokiran yang mengacu pada filtrasi deposit partikel (cake) untuk menguraikan kerumitan fenomena fouling dalam mikrofiltrasi. Pada tulisan ini dijelaskan lebih rinci mengenai mekanisme fouling baik pada mikrofiltrasi searah (dead-end) maupun aliran silang (cross-flow). Mekanisme fouling pada proses mikrofiltrasi bisa dimodelkan dengan empat model yaitu pemblokiran pori, penyempitan pori, pemblokiran pori bersamaan dengan endapan permukaan dan formasi endapan permukaan. Mekanisme tersebut berlaku pada kondisi operasional bertekanan tetap dan ukuran pori yang seragam, baik pada aliran searah ataupun silang. Hanya saja, model mekanisme pada aliran silang hanya berlaku pada kondisi awal filtrasi hingga tercapai kondisi fluks kritis.Kata kunci: air limbah; bioproses; filtrasi cake; fouling; mikrofiltrasi; model pemblokiran

Mechanism of bacterial and viral transport through microfiltration membranes

1998 ◽  
Vol 38 (4-5) ◽  
pp. 489-496 ◽  
Author(s):  
Gemunu Herath ◽  
Kazuo Yamamoto ◽  
Taro Urase
Keyword(s):  
Pore Size ◽  
Membrane Filtration ◽  
Longitudinal Direction ◽  
E Coli ◽  
Membrane Pores ◽  
Dead End ◽  
Spherical Diameter ◽  
Microfiltration Membranes ◽  
Virus Size ◽  
Wide Size Distribution

Microorganisms such as Qβ, MS2, T4 virus and several bacteria strains in Pseudomonas, Alcaligenes and E-coli groups were filtered with different pore size nuclepore and anopore flat sheet membranes in dead end mode. The obtained rejection results were analyzed with existing pore models in which the rejection is related to the ratio of solute size to pore size. The existing pore models (transport equations) were adjusted to accommodate the microfiltration range particles. The adjusted pore models showed good agreement with the obtained experimental rejection results for virus while the bacteria rejection results showed a deviation. This deviation is partially explained with the wide size distribution of bacteria. The equivalent spherical diameter can be used to represent the virus size while the oval diameter of the cells may be the best possible dimension for bacteria size in membrane filtration. This determination showed the possibility of bacteria cells approaching the membrane pores in their longitudinal direction.

Computational Fluid Dynamics (CFD) Simulation of Cross-flow Mode Operation of Membrane for Downstream Processing

2019 ◽  
Vol 13 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Anirban Banik ◽  
Tarun Kanti Bandyopadhyay ◽  
Sushant Kumar Biswal
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Filtration ◽  
Cfd Simulation ◽  
Cross Flow ◽  
Flow Mode ◽  
Computational Fluid Dynamics Cfd ◽  
The Cross ◽  
Fluent 6.3

Background: Membrane filtration process produced good quality of permeate flux due to which it is used in different industries like dairy, pharmaceutical, sugar, starch and sweetener industry, bioseparation, purification of biomedical materials, and downstream polishing etc. The cross-flow mode of operation has also been used to improve the quality of the Rubber Industrial effluent of Tripura, India. </P><P> Method: The Computational Fluid Dynamics (CFD) simulation of the cross-flow membrane is done by using ANSYS Fluent 6.3. The meshing of the geometry of the membrane is done by Gambit 2.4.6 and a grid size of 100674, the number of faces is 151651 and number of nodes being 50978 has been selected for the simulation purpose from the grid independence test. We have revised and included all patents in the manuscripts related to the membrane filtration unit. </P><P> Results: Single phase Pressure-Velocity coupled Simple Algorithm and laminar model is used for the simulation of the developed model and Fluent 6.3 used for the prediction of pressure, pressure drop, flow phenomena, wall shear stress and shear strain rate inside the module is studied for cross flow membrane. </P><P> Conclusion: From the study, it has been found that CFD simulated results hold good agreement with the experimental values.

Ultrathin Membrane Fouling Mechanism Transitions in Dead-End Filtration of Protein

2016 ◽  
Author(s):  
Karl J. P. Smith ◽  
Joshua Winans ◽  
James McGrath
Keyword(s):  
Silicon Nitride ◽  
Membrane Fouling ◽  
Cake Filtration ◽  
Nanoporous Silicon ◽  
Fouling Mechanism ◽  
Dead End ◽  
Great Utility ◽  
Key Aspects ◽  
Ultrathin Membranes ◽  
Over Time

Ultrathin membranes will likely see great utility in future membrane-based separations, but key aspects of the performance of these membranes, especially when they are used to filter protein, remain poorly understood. In this work we perform protein filtrations using new nanoporous silicon nitride (NPN) membranes. Several concentrations of protein are filtered using dead end filtration in a benchtop centrifuge, and we track fouling based on the amount of filtrate passed over time. A modification of the classic fouling model that includes the effects of using a centrifuge and allow for the visualization of a transition between pore constriction and cake filtration demonstrate that for a range of protein concentrations, cake filtration supersedes pore constriction after ∼30 seconds at 690 g.

scholarly journals Effect of Gas Sparging on Fouling and Fouling Mechanism During Microfiltration of Pineapple Juice and Coconut Water

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
A. Laorko ◽  
W. Youravong ◽  
S. Tongchitpakdee
Keyword(s):  
Hollow Fiber Membrane ◽  
Gas Injection ◽  
Cross Flow ◽  
Coconut Water ◽  
Transmembrane Pressure ◽  
Cake Filtration ◽  
Pineapple Juice ◽  
Fouling Mechanism ◽  
Gas Sparging ◽  
Cross Flow Velocity

Flux reduction due to fouling is the major problem during microfiltration. This study aimed to investigate the role of gas sparging, an effective technique for flux enhancement, on fouling and fouling mechanism during microfiltration pineapple juice and coconut water. A hollow fiber membrane was used and the experiments were performed at cross flow velocity (CFV) of 1.5 m/s, transmembrane pressure (TMP) of 0.7 bar for pineapple juice and CFV of 1.6 m/s, TMP of 0.6 bar for coconut water, as varying gas injection factors (e). It was found that the fouling mechanism during microfiltration of pineapple juice and coconut water began with complete blocking, followed by an intermediate blocking and finally cake filtration. The use of gas sparging did not affect the sequence of fouling mechanism but affected both intensity duration of these fouling mechanisms. The duration of complete blocking stage was about 5-6 min at the beginning of the microfiltration for both feed. The initial points of defined cake filtration stages reduced from 1.3 to 0.9 h for pineapple juice and 1.0 to 0.67 h for coconut water when the e was varied from 0 to 0.35. Regarding fouling resistance analysis, increase in gas injection factor could significantly reduce the reversible fouling, external irreversible fouling but internal irreversible fouling.

Experimental assessment of the efficacy of microfiltration and ultrafiltration for Cryptosporidium removal

1998 ◽  
Vol 38 (12) ◽  
pp. 103-107 ◽  
Author(s):  
T. Hirata ◽  
A. Hashimoto
Keyword(s):  
Cryptosporidium Oocyst ◽  
Cross Flow ◽  
Drinking Water Treatment ◽  
Flow Mode ◽  
Additional Experiment ◽  
Experimental Assessment ◽  
Dead End ◽  
Single Process ◽  
Scale Experiment ◽  
Annual Risk

In order to evaluate the efficacy of microfiltration and ultrafiltration for Cryptosporidium oocyst removal, a bench-scale experiment was carried out using two 0.2m2 molecules, MF (nominal pore size 0.25μm) and UF (nominal cut-off MW 13,000 daltons) in cross-flow mode at an oocyst level of 106/L. Both of the membranes eliminated the oocysts from the influents with removal efficiency estimated to be &gt;7 log10. As for the MF, an additional experiment was conducted at a much higher oocyst level up to 108 oocysts/L in both cross-flow and dead-end modes and which achieved &gt;7 log10 removal, although some oocysts appeared in the filtrate in both modes. Based on these results, microfiltration and ultrafiltration are conclusively considered to be excellent processes for drinking water treatment as a single process that produces safe (an annual risk 10−4) water from highly polluted source waters.

Introducing a slow cross-flow at the capillary outlet in comparison to conventional dead-end mode—a trajectory analysis of the effects

2008 ◽  
Vol 8 (4) ◽  
pp. 389-399
Author(s):  
A. Lerch
Keyword(s):  
Flow Field ◽  
Trajectory Analysis ◽  
Cross Flow ◽  
Flow Mode ◽  
Membrane Area ◽  
Operation Conditions ◽  
Cross Flow Filtration ◽  
Cross Section Area ◽  
Dead End ◽  
Flow Filtration

A model has been developed, based on the finite element method (FEM) of computational fluid dynamics (CFD), for the description of the complete flow field and concentration distribution inside a membrane capillary, driven in inside-out and dead-end or ‘slow’ cross-flow mode, sometimes referred to as ‘bleed flow’. Particle or floc transport and deposition have been described by trajectory analysis, i.e. superimposing the calculation of forces and torques acting on the particles or flocs, based on the previously modelled fluid flow field. The model is used to give an overview of deposition behaviour and fouling layer formation of particles and flocs of a certain size in dead-end and cross-flow filtration. Example results are shown for different sized flocs. It is shown that the choice of dead-end or cross-flow operation is more significant if small floc aggregates have to be filtered by the membrane. Small flocs will be deposited more or less homogeneously along the membrane wall after some significant distance to the capillary inlet, leaving the first part of the membrane area unused for deposition. A ‘slow’ cross-flow could be used to transport small flocs out of the capillary which entered the capillary cross section area in the neighbourhood of the axis. The faster the chosen cross-flow velocity, the larger the area. Larger flocs will be ‘accumulated’ in one resulting equilibrium trajectory and are transported to the rear end of the capillary, independent of their starting radial position at the inlet and operation conditions. It was calculated, that larger flocs will not be significantly transported out of the capillary lumen by introducing ‘slow’ cross-flow velocities at the capillaries outlet only.

scholarly journals Effects of Filtration Mode on the Performance of Gravity-Driven Membrane (GDM) Filtration: Cross-Flow Filtration and Dead-End Filtration

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 190
Author(s):  
Qian Wang ◽  
Xiaobin Tang ◽  
Heng Liang ◽  
Wenjun Cheng ◽  
Guibai Li ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Cross Flow ◽  
Drinking Water Treatment ◽  
Flow Mode ◽  
Cross Flow Filtration ◽  
Dead End ◽  
Gravity Driven ◽  
Flux Level ◽  
Flow Filtration

Gravity-driven membrane (GDM) filtration technology has been extensively in the employed drinking water treatment, however, the effect filtration mode (i.e., dead-end mode vs. cross-flow mode) on its long-term performance has not been systematically investigated. In this study, pilot-scale GDM systems were operated using two submerged filtration mode (SGDM) and cross-flow mode (CGDM) at the gravity-driven pressures 120 mbar and 200 mbar, respectively. The results showed that flux stabilization was observed both in the SGDM and CGDM during long-term filtration, and importantly the stabilized flux level of CGDM was elevated by 3.5–67.5%, which indicated that the filtration mode would not influence the occurrence of flux stability, but significantly improve the stable flux level. Interestingly, the stable flux level was not significantly improved with the increase of driven pressure, and the optimized driven pressure was 120 mbar. In addition, the GDM process conferred effective removals of turbidity, UV254, CODMn, and DOC, with average removals of 99%, 43%, 41%, and 20%, respectively. With the assistance of cross flow to avert the overaccumulation of contaminants on the membrane surface, CGDM process exhibited even higher removal efficiency than SGDM process. Furthermore, it can be found that the CGDM system can effectively remove the fluorescent protein-like substances, and the intensities of tryptophans substance and soluble microbial products were reduced by 64.61% and 55.08%, respectively, higher than that of the SGDM. Therefore, it can be determined that the filtration mode played an important role in the flux stabilization of GDM system during long-term filtration, and the cross-flow filtration mode can simultaneously improve the stabilized flux level and removal performance.

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