Intensified membrane filtration with corrugated membranes

Scott, Keith; Mahmood, Asif; Jachuck, Roshan; Hu, Bing

doi:10.1016/s0376-7388(00)00327-6

Cited by 76 publications

(44 citation statements)

References 19 publications

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“…Corrugated membranes are said to enhance flux by promoting turbulence near the membrane wall region. This, in turn, reduces concentration polarization and improves performance (Scott et al, 2000, Vanderwaal et al, 1989, Racz et al, 1986. Scott et al (2000) illustrate that corrugations can lead to energy savings up to 88% and the savings is dependent on the angle of the corrugations relative to the direction of flow with the largest savings occurring when corrugations were 90º to the direction of flow.…”

Section: Introductionmentioning

confidence: 99%

“…This, in turn, reduces concentration polarization and improves performance (Scott et al, 2000, Vanderwaal et al, 1989, Racz et al, 1986. Scott et al (2000) illustrate that corrugations can lead to energy savings up to 88% and the savings is dependent on the angle of the corrugations relative to the direction of flow with the largest savings occurring when corrugations were 90º to the direction of flow. Likewise, spacer thickness and configuration can influence localized turbulence, thus decreasing concentration polarization and increasing flux (Lipnizki andJonsson, 2002, Sablani et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Neal et al (2003) performed experiments that illustrated the deposition pattern of particles in the vicinity of different filament orientations, but observed deposition patterns were not rigorously compared or correlated to computational simulations. Scott et al (2000) performed experiments in a crossflow test cell using flat and corrugated membranes. They found that the corrugated membranes yielded greater permeate flux than the flat membranes due to a combination of increased surface area and increased scouring via enhanced mixing, which Scott et al (2000) postulated helped to disrupt the formation of concentration polarization and fouling.…”

Section: Introductionmentioning

confidence: 99%

“…Scott et al (2000) performed experiments in a crossflow test cell using flat and corrugated membranes. They found that the corrugated membranes yielded greater permeate flux than the flat membranes due to a combination of increased surface area and increased scouring via enhanced mixing, which Scott et al (2000) postulated helped to disrupt the formation of concentration polarization and fouling. More recently, correlated simulated hydraulic metrics with biofouling on membrane surfaces.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

Webb¹,

James

Hibbs³

et al. 2009

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Biofouling, the unwanted growth of biofilms on a surface, of water-treatment membranes negatively impacts in desalination and water treatment. With biofouling there is a decrease in permeate production, degradation of permeate water quality, and an increase in energy expenditure due to increased cross-flow pressure needed. To date, a universal successful and cost-effect method for controlling biofouling has not been implemented. The overall goal of the work described in this report was to use high-performance computing to direct polymer, material, and biological research to create the next generation of water-treatment membranes. Both physical (micromixers -UV-curable epoxy traces printed on the surface of a watertreatment membrane that promote chaotic mixing) and chemical (quaternary ammonium groups) modifications of the membranes for the purpose of increasing resistance to biofouling were evaluated. Creation of low-cost, efficient water-treatment membranes helps assure the availability of fresh water for human use, a growing need in both the U. S. and the world. 3 EXECUTIVE SUMMARYSection 1: Biofouling, the unwanted growth of biofilms on a surface, of water-treatment membranes has a negative economic impact in desalination and water treatment. With biofouling there is a decrease in permeate production and an increase in energy expenditure due to increased cross-flow pressure needed. Biofouling leads to increased cleaning expenditures, it accelerates the degradation of the membranes, and degrades the water quality of the permeate. To date, a universal successful and cost-effect method for controlling biofouling has not been implemented. The goal of this project is to use high-performance computing to direct polymer, material, and biological research to create the next generation of water-treatment membranes. Both physical (micromixers -UV-curable epoxy traces printed on the surface of a watertreatment membrane that promote chaotic mixing) and chemical (quaternary ammonium groups) modifications of the membranes for the purpose of increasing resistance to biofouling were evaluated.Section 2: Features (micromixers) that promote chaotic mixing were fabricated on reverseosmosis membrane surfaces and evaluated using computational models and laboratory experiments to determine their effectiveness in reducing biofouling. Computational fluid dynamics models of membrane feed channels were developed using different patterns of micromixers on the membrane surface. The shear-stress distribution along the membrane surface was simulated for steady flows along the different micromixer configurations. In addition, the hypothetical mass transfer of a tracer from the membrane surface was used as a metric to compare the amount of scouring and mixing in configurations with and without micromixers. Epoxy micromixers were printed directly onto membrane surfaces, and different patterns were evaluated experimentally. Fluorescence hyperspectral imaging results showed that regions of simulated high shear stress on the membrane co...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

Webb¹,

James

Hibbs³

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Neal et al [5] performed experiments that illustrated the deposition pattern of particles in the vicinity of different filament orientations, but observed deposition patterns were not rigorously compared or correlated to computational simulations. Scott et al [6] performed experiments in a cross-flow test cell using flat and corrugated membranes. They found that the corrugated membranes yielded greater permeate flux than the flat membranes due to a combination of increased surface area and increased scouring via enhanced mixing, which Scott et al [6] postulated helped to disrupt the formation of concentration polarization and fouling.…”

Section: Introductionmentioning

confidence: 99%

Analysis of micromixers to reduce biofouling on reverse‐osmosis membranes

Altman

Jones

et al. 2008

Environ. Prog.

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Features (micromixers) that promote chaotic mixing were fabricated on reverse-osmosis membrane surfaces and evaluated using computational models and laboratory experiments to determine their effectiveness in reducing biofouling. Computational fluid dynamics models of membrane feed channels were developed using different patterns of micromixers on the membrane surface. The shear-stress distribution along the membrane surface was simulated for steady flows along the different micromixer configurations. In addition, the hypothetical mass transfer of a tracer from the membrane surface was used as a metric to compare the amount of scouring and mixing in configurations with and without micromixers. Epoxy micromixers were printed directly onto membrane surfaces, and different patterns were evaluated experimentally. Fluorescence hyperspectral imaging results showed that regions of simulated high shear stress on the membrane corresponded to regions of lower bacterial growth in the experiments, while regions of simulated low shear stress corresponded to regions of higher bacterial growth. In addition, the presence of the micromixers appeared to reduce the overall biofouling concentration in one series of experiments, but the results were inconclusive in another series of experiments. These results indicate that while the enhancement of mixing and shear stress via micromixers may delay or mitigate the onset of localized membrane fouling from biofilms or other contaminants, the impact of micromixers on the overall performance of reverse-osmosis membranes needs further investigation.

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Mathematical model analysis on the enhancement of aeration efficiency using ladder-type flat membrane module forms in the Submerged Membrane Bio-reactor (SMBR)

Yang

et al. 2009

Sci. China Ser. E-Technol. Sci.

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The cross-flow shearing action produced from the inferior aeration in the Submerged Membrane Bio-reactor (SMBR) is an effective way to further improve anti-fouling effects of membrane modules.Based on the widely-applied vertical structure of flat membrane modules, improvements are made that ladder-type flat membrane structure is designed with a certain inclined angle θ so that the cross-flow velocity of bubble near the membrane surface can be held, and the intensity and times of elastic collision between bubbles and membrane surface can be increased. This can improve scouring action of membrane surface on aeration and reduce energy consumption of strong aeration in SMBR. By deducing and improving the mathematics model of collision between bubble and vertical flat put forward by Vries, the relatively suitable incline angle θ under certain aeration place and in certain size rang of bubble can be obtained with the computer iterative calculation technology. Finally, for many groups of ladder-type flat membrane in parallel placement in the practical application of SMBR, some suggestions are offered: the interval distance of membrane modules is 8-15 mm, and aeration should be operated at 5-7 mm among membrane modules, and the optimal design angle of trapeziform membrane is 1.7°-2.5°. membrane bioreactor, flat membrane, membrane module form, aeration, mathematical modelIn the Submerged Membrane Bio-reactors (SMBR), the bubble produced during the aerating can not only provide the necessary oxygen for the microorganisms, but also results in a gas-liquid cross-flow on the membrane surface and an increased shearing force. In this way, the enhanced aerating intensity can increase the disorderly cross-flow and the shearing force on the membrane surface, commix the laminar flow boundary layer, inhibit the growth and condensation of cake architecture, and thus delay the effect of concentration polarization, which is an effective way to control the membrane fouling [1] .However, too high aerating intensity will do harm to the activated sludge flocs, decrease inter-effect of the microorganisms, inorganic granule and extra-cellular polymeric substances and thus aggregate Zoogloeadis with more extra-cellular polymeric substances released, which might shorten sludge floc dimension, and even worsen the membrane filtration process [2] . Moreover, the energy-consumption of the aerating accounts for more than 80% [3] , thus the high cost of operation has been the main obstacle of the SMBR in the industrial application.

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Intensified membrane filtration with corrugated membranes

Cited by 76 publications

References 19 publications

Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

Analysis of micromixers to reduce biofouling on reverse‐osmosis membranes

Mathematical model analysis on the enhancement of aeration efficiency using ladder-type flat membrane module forms in the Submerged Membrane Bio-reactor (SMBR)

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