Comparative experimental study on fouling mechanisms in nano-porous membrane: cheese whey ultrafiltration as a case study

2016 ◽  
Vol 74 (12) ◽  
pp. 2737-2750 ◽  
Author(s):  
Mohammad Torkamanzadeh ◽  
Mohsen Jahanshahi ◽  
Majid Peyravi ◽  
Ali Shokuhi Rad
Keyword(s):  
Membrane Fouling ◽  
Porous Membrane ◽  
Quantitative Prediction ◽  
Layer Formation ◽  
Cake Filtration ◽  
Operational Conditions ◽  
Cake Layer ◽  
Classical Models ◽  
Pore Blockage ◽  
Relative Errors

Determination of fouling mechanisms and accurate quantitative prediction of nano-porous membrane behavior are of great interest in membrane processes. This work has focused on a comprehensive comparison of two classical and new fouling models. Different operational conditions were tested to analyze the level of agreement of these models with experimental observation. Whey solutions of 8, 0.8 and 0.5 g/L were ultrafiltered in transmembrane pressures (TMPs) of 300 and 500 KPa through a synthesized polyethersulfone/copolymer blend membrane. Fouling mechanisms and the effect of different combinations of TMPs and protein concentrations were determined and analyzed by fitting the experimental data to different models. Based on the results obtained from classical models, it was found that the predictions of the cake layer formation model were quite acceptable, followed by the intermediate blocking model. The new combined pore blockage-cake filtration model, however, was found to be very successful in predicting the flux decline over time for every operational condition tested, with all relative errors of prediction less than 5%. The latter also showed a good performance in the transition from the pore blockage mechanism to cake layer formation.

Exerting ultrasound to control the membrane fouling in filtration of anaerobic activated sludge—mechanism and membrane damage

2008 ◽  
Vol 57 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Xianghua Wen ◽  
Pengzhe Sui ◽  
Xia Huang
Keyword(s):  
Activated Sludge ◽  
Hydroxyl Radicals ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Chemical Interaction ◽  
Membrane Surface ◽  
Membrane Damage ◽  
Operational Conditions ◽  
Fouling Control ◽  
Cake Layer

In this study, ultrasound was applied to control membrane fouling development online in an anaerobic membrane bioreactor (AMBR). Experimental results showed that membrane fouling could be controlled effectively by ultrasound although membrane damage may occur under some operational conditions. Based upon the observation on the damaged membrane surface via SEM, two mechanisms causing membrane damage by exerting ultrasound are inferred as micro particle collide on the membrane surface and chemical interaction between membrane materials and hydroxyl radicals produced by acoustic cavitations. Not only membrane damage but also membrane fouling control and membrane fouling cleaning were resulted from these mechanisms. Properly selecting ultrasonic intensity and working time, and keeping a certain thickness of cake layer on membrane surface could be effective ways to protect membrane against damage.

A network-based approach to interpreting pore blockage and cake filtration during membrane fouling

2017 ◽  
Vol 528 ◽  
pp. 112-125 ◽  
Author(s):  
Qi Han ◽  
Weiyi Li ◽  
Thien An Trinh ◽  
Xin Liu ◽  
Jia Wei Chew
Keyword(s):  
Membrane Fouling ◽  
Cake Filtration ◽  
Pore Blockage

Integrating activated sludge floc size information in MBR fouling modeling

2015 ◽  
Vol 71 (7) ◽  
pp. 1073-1080 ◽  
Author(s):  
T. A. Cao ◽  
G. Van De Staey ◽  
I. Y. Smets
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Three Dimensional ◽  
Strong Impact ◽  
Layer Formation ◽  
Floc Size ◽  
Pore Blocking ◽  
Three Dimensional Modeling ◽  
Cake Layer ◽  
Floc Size Distributions

Although studied extensively, modeling fouling phenomena in membrane bioreactors (MBRs) remains challenging. It has been well established that cake layer formation and pore blocking have a strong impact on the filtration performance but how to capture that in comprehensive models is not fully defined yet. Since it has been shown that bioflocculation characteristics of activated sludge have a clear link with (the extent of) membrane fouling, this study integrates activated sludge floc size (i.e., particle size distribution) information in the model for pore blocking and cake layer formation with a focus on constant flux operated MBRs. Based on these floc size distributions, a three-dimensional modeling and visualization of the cake layer is envisaged which can then provide the required input information (e.g., the porosity of the cake layer) for the fouling model. The model is calibrated and validated on the basis of experimental data from Hwang et al. (2012) in ‘Membrane bioreactor: TMP rise and characterization of biocake structure using CLSM-image analysis’ (see J. Membr. Sci. 419–420, 33–41).

scholarly journals Investigation of membrane fouling mechanism of intracellular organic matter during ultrafiltration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weiwei Huang ◽  
Yuanhong Zhu ◽  
Bingzhi Dong ◽  
Weiwei Lv ◽  
Quan Yuan ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chlorella Vulgaris ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Layer Formation ◽  
Fouling Control ◽  
Fouling Mechanism ◽  
Cake Layer ◽  
Severe Degree ◽  
Filtration Flux

AbstractThis study investigated the ultrafiltration (UF) membrane fouling mechanism of intracellular organic matter (IOM) from Chlorella vulgaris (CV) and Microcystis aeruginosa (MA). Both CV- and MA-IOM caused severe membrane fouling during UF; however, there were significant differences in the membrane fouling by these two materials. Neutral hydrophilic (N-HPI) compounds were the organics that caused the most severe membrane fouling during CV-IOM filtration, whereas the MA-IOM membrane fouling was induced by mainly hydrophobic (HPO) organics. From an analysis based on Derjaguin–Landau–Verwey–Overbeek theory, it was found that the interaction energy between the membrane and foulants in the later stage of filtration was the major factor determining the efficiency of filtration for both CV-IOM and MA-IOM. The TPI organics in CV-IOM fouled the membrane to a more severe degree during the initial filtration flux; however, when the membrane surface was covered with CV-IOM foulants, the N-HPI fraction of CV-IOM caused the most severe membrane fouling because its attractive energy with the membrane was the highest. For MA-IOM, regardless of the initial filtration flux or the late stage of filtration, the HPO organics fouled the membrane to the greatest extent. An analysis of modified filtration models revealed that cake layer formation played a more important role than other fouling mechanisms during the filtration of CV-IOM and MA-IOM. This study provides a significant understanding of the membrane fouling mechanism of IOM and is beneficial for developing some strategies for membrane fouling control when treating MA and CV algae-laden waters.

Comparison of the Filterability of Mineral, Organic and Mixed Suspensions Application to Water Clarification

2012 ◽  
Author(s):  
P. Choksuchart Sridang ◽  
M. Heran ◽  
A. Grasmick
Keyword(s):  
Activated Carbon ◽  
Hydraulic Resistance ◽  
Membrane Fouling ◽  
Ferric Hydroxide ◽  
Membrane System ◽  
Porous Membrane ◽  
Resistance Coefficient ◽  
Permeability Evolution ◽  
Cake Filtration ◽  
Mineral Suspensions

Filtration operations were conducted on porous membrane to evaluate the specific contribution of the main fractions encountered in raw water (solids in suspension, soluble, or colloidal compounds) on the system permeability evolution during industrial operations. Experiments were conducted in a frontal filtration mode with single or mixed synthetic suspensions (clay, ferric hydroxide, activated carbon, latex, and humic acids). Results showed a wild specific resistance coefficient (α.W) difference between mineral and organic suspensions. The α.W coefficient increased with suspended solids concentrations. On the other hand, no actual differences were observed between the tested mineral suspensions, which also presented no actual differences in particle size distribution. In the same condition, latex suspensions composed by smaller elements induced higher hydraulic resistance, comparatively to mineral suspension, the resistance coefficient values were ten to one hundred times greater than the mineral suspensions. Nevertheless, a latex suspensions conditioning with FeCl3 allowed a notably reducing of the resistance coefficient. Moreover, experiments on humic acid suspension pointed out the membrane fouling during filtration, which could disappear in the presence of activated carbon in the suspension. Since similar results were obtained in an immersed membrane system, it can be considered that this methodology can be developed to characterise the filterability of natural suspensions, and optimise the suspension conditioning. Key words: Water clarification, cake filtration, porous membrane, hydraulic resistance, synthetic suspensions

Influence of water compositions on fouling of plane organic membrane in frontal filtration: application to water and wastewater clarification

2010 ◽  
Vol 61 (9) ◽  
pp. 2283-2291
Author(s):  
P. Sridang ◽  
P. Wanichapichart ◽  
A. Grasmick
Keyword(s):  
Hydraulic Resistance ◽  
Membrane Fouling ◽  
Film Formation ◽  
Applied Pressure ◽  
Porous Membrane ◽  
Resistance Coefficient ◽  
Treated Wastewater ◽  
Feed Water ◽  
Cake Filtration ◽  
Inorganic Matter

The aim of this study was to evaluate and quantify the filterability of suspended/soluble organic and suspended inorganic matter in a condition without and with chemical conditioning on membrane fouling using cake filtration model. The experiments were conducted with different feed water concentrations under a given TMP (0.2 to 0.5 bar). The fouling potential was examined and described in terms of resistance coefficient (α·W) and specific resistance (α). The results showed an increase of α·W and α within the concentration of wastewater samples tested. The soluble fractions in wastewater induced fouling and its mechanism was due both to the interaction of soluble organic components and also some of the particular colloids in MLSS, causing irreversible fouling, followed by thin film formation on membrane surfaces with low porosity, dense structure and also internal fouling. This phenomenon promoted the values of α·W and α from final treated wastewater 5–20 times higher than in bentonite suspension and on reservoir surface water. Higher pressure than 0.2 bar induced greater hydraulic resistance values than lower applied pressure. The pore size of the porous membrane did not show any difference in the values of α·W and α obtained, but they mostly depended on the water composition tested. The hydraulic resistance values appeared largely to minimise when using chemical conditioning because of cake forming as a dynamic membrane that reduced the irreversible fouling phenomena giving a constant filtration rate.

Application of the ceramic membrane with hydrophobic skin layer to separation of activated sludge

1997 ◽  
Vol 35 (8) ◽  
pp. 137-144 ◽  
Author(s):  
Tsuyoshi Nomura ◽  
Takao Fujii ◽  
Motoyuki Suzuki
Keyword(s):  
Activated Sludge ◽  
Pore Size ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Porous Ceramic ◽  
Porous Membrane ◽  
Skin Layer ◽  
Gas Permeation ◽  
Wide Range ◽  
Cake Layer

Porous membrane of poly(tetrafluoroethylene) (PTFE) was formed on the surface of porous ceramic tubes by means of heat treatment of the PTFE particles deposit layer prepared by filtering PTFE microparticles emulsified in aqueous phase. By means of inert gas permeation, pore size was determined and compared with scanning electron micrograph observation. Also rejection measurement of aqueous dextran solutions of wide range of molecular weights showed consistent results regarding the pore size. Since the membrane prepared by this method is stable and has unique features derived from PTFE, it is expected that the membrane has interesting applications in the field of water treatment. Membrane separation of activated sludge by this composite membrane and original ceramics membrane showed that the PTFE membrane gives better detachability of the cake layer formed on the membrane. This might be due to the hydrophobic nature of the PTFE skin layer.

scholarly journals Effect of moisture condensation on vapour transmission through porous membranes

2021 ◽  
pp. 152808372110142
Author(s):  
Ariana Khakpour ◽  
Michael Gibbons ◽  
Sanjeev Chandra
Keyword(s):  
Water Vapour ◽  
Moisture Diffusion ◽  
Porous Membrane ◽  
Water Evaporation ◽  
Porous Membranes ◽  
Water Vapour Concentration ◽  
Vapour Concentration ◽  
Vapour Diffusion ◽  
Pore Blockage ◽  
The Impact

Porous membranes find natural application in various fields and industries. Water condensation on membranes can block pores, reduce vapour transmissibility, and diminish the porous membranes' performance. This research investigates the rate of water vapour transmission through microporous nylon and nanofibrous Gore-Tex membranes. Testing consisted of placing the membrane at the intersection of two chambers with varied initial humidity conditions. One compartment is initially set to a high ([Formula: see text]water vapour concentration and the other low ([Formula: see text], with changes in humidity recorded as a function of time. The impact of pore blockage was explored by pre-wetting the membranes with water or interposing glycerine onto the membrane pores before testing. Pore blockage was measured using image analysis for the nylon membrane. The mass flow rate of water vapour ( ṁv) diffusing through a porous membrane is proportional to both its area (A) and the difference in vapour concentration across its two faces ([Formula: see text], such that [Formula: see text] where K is defined as the moisture diffusion coefficient. Correlations are presented for the variation of K as a function of [Formula: see text]. Liquid contamination on the porous membrane has been shown to reduce the moisture diffusion rate through the membrane due to pore blockage and the subsequent reduced open area available for vapour diffusion. Water evaporation from the membrane's surface was observed to add to the mass of vapour diffusing through the membrane. A model was developed to predict the effect of membrane wetting on vapour diffusion and showed good agreement with experimental data.

Correlation between membrane fouling and soluble/colloidal organic substances in membrane bioreactors for municipal wastewater treatment

2005 ◽  
Vol 51 (6-7) ◽  
pp. 1-8 ◽  
Author(s):  
B. Lesjean ◽  
S. Rosenberger ◽  
C. Laabs ◽  
M. Jekel ◽  
R. Gnirss ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Size Exclusion ◽  
Water Phase ◽  
Parallel Operation ◽  
Municipal Wastewater Treatment ◽  
Operational Conditions ◽  
The Difference

Two similar membrane bioreactors of 2 m3 each were operated in parallel over two years under the same operational conditions, fed with the same municipal wastewater. The only process and operational difference between both pilot plants was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite parallel operation, the two MBRs exhibited different fouling rates and decreases in permeability. These differences could not be accounted for by MLSS concentrations, loading rates, or filtration flux. In a one-year investigation, soluble and colloidal organic material in the activated sludge of both MBR was regularly analysed by spectrophotometric and Size Exclusion Chromatography (SEC) methods. The larger organic molecules present in the sludge water phase (i.e. polysaccharides, proteins and organic colloids) originating from microbial activity (extracellular polymeric substances) were found to impact on the fouling and to explain the difference in membrane performance between the two MBR units. In both pilot plants, a linear relationship could be clearly demonstrated between the fouling rate of the membrane and the concentration of polysaccharides in the sludge water phase during a 5 month operational period at an SRT of 8 days.

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