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dc.contributor.authorDreszer, C.
dc.contributor.authorVrouwenvelder, Johannes S.
dc.contributor.authorPaulitsch-Fuchs, Astrid H.
dc.contributor.authorZwijnenburg, Arie
dc.contributor.authorKruithof, Joop C.
dc.contributor.authorFlemming, Hans Curt
dc.date.accessioned2015-08-03T10:59:00Z
dc.date.available2015-08-03T10:59:00Z
dc.date.issued2013-02
dc.identifier.citationDreszer, C., Vrouwenvelder, J. S., Paulitsch-Fuchs, A. H., Zwijnenburg, A., Kruithof, J. C., & Flemming, H.-C. (2013). Hydraulic resistance of biofilms. Journal of Membrane Science, 429, 436–447. doi:10.1016/j.memsci.2012.11.030
dc.identifier.issn03767388
dc.identifier.doi10.1016/j.memsci.2012.11.030
dc.identifier.urihttp://hdl.handle.net/10754/562629
dc.description.abstractBiofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness after 4 days at a flux of 100Lm-2h-1 (97μm) was in the same order of magnitude as the thickness of a biofilm at a flux of 20Lm-2h-1 (114μm). An increase of flux caused an increased biofilm resistance while a decrease of flux caused a decreased resistance. The effect was reversible. It is suggested that the biofilm resistance is mainly attributed to EPS, probably due to the tortuosity ("hair-in-sink-effect") of the biopolymers to water molecules travelling across the biofilm. The data show clearly that biofilm resistance (6×1012m-1) was high compared to the intrinsic resistance of the employed MF membrane (5×1011m-1). However, in nanofiltration (intrinsic membrane resistance ca. 2×1013m-1) and reverse osmosis membranes (intrinsic resistance ca. 9×1013m-1), the biofilm will not contribute significantly to the overall resistance. © 2012 Elsevier B.V.
dc.description.sponsorshipThis work was performed at Wetsus, Centre of Excellence for Sustainable Water Technology (www.wetsus.nl). Wetsus is funded by the Dutch Ministry of Economic Affairs, the European Union European Regional Development Fund, the Province of Fryslan, the city of Leeuwarden and by the EZ-KOMPAS Program of the "Samenwerkingsverband Noord-Nederland". The authors like to thank the participants of the research theme "Biofouling" and Evides waterbedrijf for the fruitful discussions and their financial support. In addition the authors would especially like to thank the students Judita Laurinonyte, Nathalie Juranek and Zhen Xiang for their great support with the experimental work in the laboratory and colleague Witold Michalowski for the help with the CLSM. The fruitful and inspiring discussions with Tony Fane (NTU Singapore), Christian Mayer (Essen), Wiebren Veeman (Essen) and Harry Ridgway (US) about the background for understanding the reasons for the hydraulic resistance by the EPS is greatly acknowledged. The graphic expression "hair-in-sink-effect" is owed to Yu Shiping (NTU Singapore).
dc.publisherElsevier BV
dc.subjectBiofouling
dc.subjectConcentration polarization
dc.subjectEPS
dc.subjectHydraulic biofilm resistance
dc.subjectNF
dc.subjectPolarization
dc.subjectRO
dc.subjectTrans membrane pressure
dc.subjectUF
dc.subjectUltrafiltration
dc.titleHydraulic resistance of biofilms
dc.typeArticle
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.contributor.departmentEnvironmental Science and Engineering Program
dc.identifier.journalJournal of Membrane Science
dc.contributor.institutionWetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. box 1113, 8900 CC Leeuwarden, Netherlands
dc.contributor.institutionUniversity Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Universitätsstrasse 5, 45141 Essen, Germany
dc.contributor.institutionDepartment of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, Netherlands
kaust.personVrouwenvelder, Johannes S.


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