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dc.contributor.authorSiddiqui, Amber
dc.contributor.authorLehmann, S.
dc.contributor.authorHaaksman, V.
dc.contributor.authorOgier, J.
dc.contributor.authorSchellenberg, C.
dc.contributor.authorvan Loosdrecht, M.C.M.
dc.contributor.authorKruithof, J.C.
dc.contributor.authorVrouwenvelder, Johannes S.
dc.identifier.citationSiddiqui A, Lehmann S, Haaksman V, Ogier J, Schellenberg C, et al. (2017) Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization. Water Research. Available:
dc.description.abstractThe porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric calculations based on spacer strand count together with cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography scanning (CT). The CT method was introduced as an alternative for the other five already existing and applied methods in practice.Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types.Depending on the maximum deviation of the porosity measurement techniques from –6% to +6%, (i) the linear velocity deviations were −5.6% and +6.4% respectively and (ii) the pressure drop deviations were –31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for numerical modelling purposes. The porosity has a linear relationship with the flow velocity and a superlinear effect on the pressure drop. Accurate porosity data are essential to evaluate feed spacer performance in spiral-wound membrane systems. Porosity of spacer-filled feed channels has a strong impact on membrane performance and biofouling impact.
dc.description.sponsorshipThe research reported in this publication was supported by funding from King Abdullah University of Science and Technology.
dc.publisherElsevier BV
dc.rights© 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
dc.subjectPorosity measurement methods
dc.subjectSpacer-filled channel
dc.subjectFeed spacer geometry modification
dc.subjectLinear flow velocity
dc.subjectPressure drop
dc.titlePorosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentBioscience Program
dc.contributor.departmentEnvironmental Science and Engineering Program
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.identifier.journalWater Research
dc.contributor.institutionLANXESS BU Liquid Purification Technologies, R&D Membranes, 06803 Bitterfeld-Wolfen, Germany
dc.contributor.institutionDepartment of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
dc.contributor.institutionWetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
kaust.personSiddiqui, Amber
kaust.personVrouwenvelder, Johannes S.

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© 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Except where otherwise noted, this item's license is described as © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license