scholarly journals Ingredient-Wise Study of Flux Characteristics in the Ceramic Membrane Filtration of Uncontaminated Synthetic Metalworking Fluids, Part 2: Analysis of Underlying Mechanisms

1999 ◽  
Vol 122 (4) ◽  
pp. 746-752 ◽  
Author(s):  
Steven J. Skerlos ◽  
N. Rajagopalan ◽  
Richard E. DeVor ◽  
Shiv G. Kapoor ◽  
V. Don Angspatt
Keyword(s):  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Environmental Scanning Electron Microscopy ◽  
Lubricant Additive ◽  
Metalworking Fluids ◽  
Environmental Scanning ◽  
Flux Decline ◽  
Cake Layer ◽  
Underlying Mechanisms

Part 2 of this paper reveals the predominant mechanism of flux decline during microfiltration of the synthetic MWF described in Part 1 of this paper. An analysis of flux data obtained during the experimental investigation suggests that adsorptive interactions occur at the membrane surface. Field Emission Environmental Scanning Electron Microscopy (FE-ESEM) images of aluminum oxide membranes after MWF microfiltration illustrate that adsorption leads to a reduction in pore diameter that serves to reduce flux. The majority of the adsorption is accounted for by a single lubricant additive in the MWF formulation. FE-ESEM images also reveal that the mechanism of flux decline for the defoamer varies depending on the presence of lubricant additive in solution. In the absence of lubricant additive, the defoamer forms a cake layer at the membrane surface. In the presence of the lubricant additive, the defoamer adsorbs to the surface of the membrane with the lubricant additive to constrict pores. In contrast to the lubricant additive and defoamer, base fluid flux decline observed after specialty additive exposure cannot be accounted for by adsorption leading to pore constriction. [S1087-1357(00)01203-X]

Behavior of micro-particles in monolith ceramic membrane filtration with pre-coagulation

2004 ◽  
Vol 50 (12) ◽  
pp. 317-325 ◽  
Author(s):  
H. Yonekawa ◽  
Y. Tomita ◽  
Y. Watanabe
Keyword(s):  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Flow Analysis ◽  
Ceramic Membranes ◽  
End Point ◽  
Micro Particles ◽  
Dead End ◽  
Cake Layer ◽  
The Dead

This paper is intended to clarify the characteristics unique to monolith ceramic membranes with pre-coagulation by referring to the behavior of micro-particles. Flow analysis and experiments have proved that monolith ceramic membranes show a unique flow pattern in the channels within the element, causing extremely rapid flocculation in the channel during dead-end filtration. It was assumed that charge-neutralized micro-particles concentrated near the membrane surface grow in size due to flocculation, and as a result, coarse micro-particles were taken up by the shearing force to flow out. As the dead end points of flow in all the channels are located near the end of the channels with higher filterability, most of the flocculated coarse particles are formed to a columnar cake intensively at the dead end point. Therefore cake layer forming on the membrane other than around the dead end point is alleviated. This behavior of particle flocculation and cake formation at the dead end point within the channels are unique characteristics of monolith ceramic membranes. This is why all monolith ceramic membrane water purification systems operating in Japan do not have pretreatment equipment for flocculation and sedimentation.

Ingredient-Wise Study of Flux Characteristics in the Ceramic Membrane Filtration of Uncontaminated Synthetic Metalworking Fluids, Part 1: Experimental Investigation of Flux Decline

1999 ◽  
Vol 122 (4) ◽  
pp. 739-745 ◽  
Author(s):  
Steven J. Skerlos ◽  
N. Rajagopalan ◽  
Richard E. DeVor ◽  
Shiv G. Kapoor ◽  
V. Don Angspatt
Keyword(s):  
Experimental Investigation ◽  
Machine Tool ◽  
Health Risks ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Residual Effects ◽  
Metalworking Fluids ◽  
Membrane Filters ◽  
Flux Decline ◽  
Productivity Decline

Membrane Filtration (MF) technology can remove microbes, particulates, and tramp oils that contaminate metalworking fluids (MWFs). Consequently MF has the potential to reduce health risks and extend MWF life in the machine tool industry. This research assesses the productivity of ceramic membrane filters during filtration of synthetic MWFs and examines the contribution of MWF chemical ingredients to productivity decline. The majority of the chemistry comprising typical synthetic MWFs has negligible impact on MF productivity. However, specialty additives such as lubricants, defoamers, and biocides can significantly reduce MF productivity. Results show that slight variations in formulation can dominate the productivity of the process. Specialty additives can also impart residual effects on the membrane that adversely impact productivity in subsequent applications of the ceramic membrane. [S1087-1357(00)01103-5]

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

Organic colloids and their influence on low-pressure membrane filtration

2004 ◽  
Vol 50 (12) ◽  
pp. 311-316 ◽  
Author(s):  
C. Laabs ◽  
G. Amy ◽  
M. Jekel
Keyword(s):  
Wastewater Treatment ◽  
Glass Fiber ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Treatment Plant ◽  
Low Pressure ◽  
Colloidal Solutions ◽  
Cake Layer ◽  
Stirred Cell ◽  
Macromolecular Component

Wastewater treatment by low-pressure membrane filtration (MF and UF) is affected to a large extent by macromolecules and colloids. In order to investigate the influence of organic colloids on the membrane filtration process, colloids were isolated from a wastewater treatment plant effluent using a rotaryevaporation pre-concentration step followed by dialysis. Stirred cell tests were carried out using redissolved colloids, with and without additional glass fiber filtration. After constant pressure membrane filtration of 190 L/m2, the initial flux had declined by 50% for colloids > 6-8 kD (glass fiber filtered) with a hydrophilic MF membrane and for colloids >12-14 kD (glass fiber filtered) with a hydrophobic MF membrane. For the non-filtered colloidal solutions, the flux decline was even steeper with the flux being below 10% of the initial flux after 190 L/m2 were passed through the membranes. As with larger particles, colloids form a filtration cake layer on top of the membrane surface when used as isolates without prior filtration. This filtration cake is easily removed during backwashing. However, polysaccharides as a macromolecular component of the colloid isolate cause severe fouling by the formation of a gel layer on the membrane surface that is difficult to remove completely.

scholarly journals Ozone Chemically Enhanced Backwash for Ceramic Membrane Fouling Control in Cyanobacteria-Laden Water

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 213
Author(s):  
Stéphane Venne ◽  
Onita D. Basu ◽  
Benoit Barbeau
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Costs ◽  
Fouling Control ◽  
Dead End ◽  
Cake Layer ◽  
Flow Experiments

Membrane fouling in surface waters impacted by cyanobacteria is currently poorly controlled and results in high operating costs. A chemically enhanced backwash (CEB) is one possible strategy to mitigate cyanobacteria fouling. This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in filtered surface water on a ceramic ultrafiltration membrane. Batch ozonation tests and dead-end, continuous flow experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon. In all tests, the ozone was shown to react more rapidly with the filtered surface water foulants than with cyanobacteria. In addition, the ozone CEB demonstrated an improved mitigation of irreversible fouling over 2 cycles versus a single CEB cycle; indicating that the ozone CEB functioned better as the cake layer developed. Ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface during filtration, which then becomes more hydraulically reversible. In fact, the ozone CEB reduced the fouling resistance by 35% more than the hydraulic backwash when the cake was more compressed.

Modeling NOM fouling of low pressure membranes: impact of membrane properties and NOM characteristics

2008 ◽  
Vol 8 (1) ◽  
pp. 75-83
Author(s):  
NoHwa Lee ◽  
John Pellegrino ◽  
Gary Amy
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Principal Component ◽  
Low Pressure ◽  
Time Frame ◽  
Membrane Properties ◽  
Flux Decline ◽  
Cake Layer ◽  
Highly Correlated ◽  
Significant Flux

This research attempted to identify characteristic coordinates responsible for significant flux decline in low pressure membrane filtration, and to explain relationships among those coordinates with a modeling approach. A Pearson's correlation matrix supported that significant flux decline over a short time frame (low delivered DOC) is highly correlated with high molecular weight (MW) components of NOM. Simulations of flux decline by model equations were close to the experimental results revealing that low pressure membrane fouling is dominantly affected by NOM characteristics and membrane properties. One source water, exhibiting the highest flux decline, showed mostly cake formation as a fouling mechanism. The results indicate that significant flux decline is caused by high MW components leading to formation of a cake layer. Principal component analysis (PCA) revealed that high MW polysaccharides are the most important NOM component affecting significant membrane fouling.

Description of different effects of in-line coagulation upon semi-dead-end ultrafiltration

2003 ◽  
Vol 3 (5-6) ◽  
pp. 337-344 ◽  
Author(s):  
W. Doyen ◽  
R. Vandaele ◽  
B. Molenberghs ◽  
J. Cromphout ◽  
P. Bielen ◽  
...  
Keyword(s):  
Surface Water ◽  
Membrane Surface ◽  
Environmental Scanning Electron Microscopy ◽  
High Volume ◽  
High Water ◽  
Transmembrane Pressure ◽  
Water Recovery ◽  
Dead End ◽  
Cake Layer ◽  
Cake Porosity

This paper describes the results of research focussed on the different effects of in-line coagulation (FeCl3), towards the operation of semi-dead-end UF for drinking water and process water production starting from surface water. In this research, firstly the effects of the use of FeCl3 on the formed cake were studied, by both direct and indirect measurements. Using the ESEM technique (environmental scanning electron microscopy), which enables one to make pictures of wet samples, we observed that cake thickness was much higher upon use of FeCl3 (20 instead of 2 μm). As a result, the cake porosity was calculated to be much higher with than without coagulant use (93% instead of 37%). From the stability (nonincreasing) of the starting transmembrane pressure (TMP) in the successive filtration cycles, upon semidead-end operation, it was concluded that cake layer was less prone to adhere to the membrane surface when using coagulant. This is even more emphasized once the dosing is stopped, as a consequence the TMP rises very steeply under difficult circumstances, such as; high flux rates, high water recovery rates, and the use of membranes made from polymers with high adsorption properties. Secondly, indirect effects of the use of coagulant on filtration behaviour were investigated. Thus, it was found that TMP increase in the filtration cycle was much lower, due to depth filtration in the formed high-volume cake, and TMP was much more stable over a long time. These observations were in good agreement with found higher cake porosity. Moreover, it was observed that due to the use of a coagulant, the influences of membrane polymer nature and membrane structure disappeared, cleaning action could be postponed and cleaning aggressiveness could be lowered. In addition, water recovery and flux rate could be increased, and influence of seasonal water quality variations could be better faced. Finally, it was found that the treatment of surface water with high DOC content (e.g. 10 mg DOC/l) was enabled.

The Fluid Mechanics of Membrane Filtration

2007 ◽  
Author(s):  
Jack S. Hale ◽  
Alison Harris ◽  
Qilin Li ◽  
Brent C. Houchens
Keyword(s):  
Membrane Filtration ◽  
Concentration Polarization ◽  
Membrane Surface ◽  
Convective Transport ◽  
Contaminated Water ◽  
Permeate Flux ◽  
Large Pressure ◽  
Cake Layer ◽  
Large Pressure Gradient ◽  
Concentration Polarization Layer

Reverse osmosis and nanofiltration membranes remove colloids, macromolecules, salts, bacteria and even some viruses from water. In crossflow filtration, contaminated water is driven parallel to the membrane, and clean permeate passes through. A large pressure gradient exists across the membrane, with permeate flow rates two to three orders of magnitude smaller than that of the crossflow. Membrane filtration is hindered by two mechanisms, concentration polarization and caking. During filtration, the concentration of rejected particles increases near the membrane surface, forming a concentration polarization layer. Both diffusive and convective transport drive particles back into the bulk flow. However, the increase of the apparent viscosity in the concentration polarization layer hinders diffusion of particles back into the bulk and results in a small reduction in permeate flux. Depending on the number and type of particles present in the contaminated water, the concentration polarization will either reach a quasi-steady state or particles will begin to deposit onto the membrane. In the later case, a cake layer eventually forms on the membrane, significantly reducing the permeate flux. Contradictive theories suggest that the cake layer is either a porous solid or a very viscous (yield stress) fluid. New and refined models that shed light on these theories are presented.

scholarly journals A Study on Membrane Filtration Characteristics of Methanogenic Mixed Liquor in Two Phase Anaerobic Digestion of Food Waste

2020 ◽  
Vol 42 (3) ◽  
pp. 151-163
Author(s):  
Min-Ju Park ◽  
Gyu-Tae Seo
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Solid Retention Time ◽  
Two Phase ◽  
Mixed Liquor ◽  
Cross Flow Filtration ◽  
Cake Layer

Objectives:An experimental study was conducted to investigate the membrane filtration characteristics of mixed liquor in methanogenic reactor to extend solid retention time (SRT) in food waste anaerobic digestion system.Methods:On the basis of the particle size distribution (0.5~700 µm) of the methanogenic mixed liquor, three grade membranes (MF, UF, NF) were tested in a stirred cell filtration and a plate type module. Furthermore foulants of membrane, especially UF, was investigated by SEM-EDS, FTIR, SEC.Results and Discussion:As a result UF membrane was selected for stable filtration of the liquor in terms of flux (2.51 L/m<sup>2</sup>･h･bar) and the flux recovery (100%) as well as filtration resistance (Total 7.15.E+13 m<sup>-1</sup>). Average flux was 18 L/m<sup>2</sup>･h･bar for the selected UF membrane in cross flow filtration using a flat plate module. The filtration results showed that membrane fouling was caused by gel and cake layer formed on the membrane surface and 90% of the initial flux could be recovered by physical washing. It was identified that major fouling causing materials were byproducts of carbohydrate and protein decomposition, and small amount of inorganic substance detected on the membrane surface were salt and struvite like materials.Conclusions:Based on the membrane filtration characteristics analyzed from the study, the UF membrane coupled anaerobic digestion is feasible to be applied as a novel food waste treatment system for SRT extension of the methanogenic reactor.

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