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dc.contributor.authorVillacorte, Loreen O.
dc.contributor.authorEkowati, Yuli
dc.contributor.authorCalix-Ponce, Helga N.
dc.contributor.authorSchippers, Jan Cornelis
dc.contributor.authorAmy, Gary L.
dc.contributor.authorKennedy, Maria Dolores
dc.date.accessioned2015-08-24T08:36:43Z
dc.date.available2015-08-24T08:36:43Z
dc.date.issued2015-03
dc.identifier.issn00431354
dc.identifier.pmid25543240
dc.identifier.doi10.1016/j.watres.2014.12.012
dc.identifier.urihttp://hdl.handle.net/10754/575729
dc.description.abstractTransparent exopolymer particles (TEP) and their precursors produced by phyto-/bacterio-planktons in fresh and marine aquatic environments are increasingly considered as a major contributor to organic/particulate and biological fouling in micro-/ultra-filtration and reverse osmosis membrane (RO) systems. However, currently established methods which are based on Alcian blue (AB) staining and spectrophotometric techniques do not measure TEP-precursors and have the tendency to overestimate concentration in brackish/saline water samples due to interference of salinity on AB staining. Here we propose a new semi-quantitative method which allows measurement of both TEP and their colloidal precursors without the interference of salinity. TEP and their precursors are first retained on 10kDa membrane, rinsed with ultra-pure water, and re-suspended in ultra-pure water by sonication and stained with AB, followed by exclusion of TEP-AB precipitates by filtration and absorbance measurement of residual AB. The concentration is then determined based on the reduction of AB absorbance due to reaction with acidic polysaccharides, blank correction and calibration with Xanthan gum standard. The extraction procedure allows concentration of TEP and their pre-cursors which makes it possible to analyse samples with a wide range of concentrations (down to <0.1mg Xeq/L). This was demonstrated through application of the method for monitoring these compounds in algal cultures and a full-scale RO plant. The monitoring also revealed that concentrations of the colloidal precursors were substantially higher than the concentration of TEP themselves. In the RO plant, complete TEP removal was observed over the pre-treatment processes (coagulation-sedimentation-filtration and ultrafiltration) but the TEP precursors were not completely removed, emphasising the importance of measuring this colloidal component to better understand the role of TEP and acidic polysaccharides in RO membrane fouling.
dc.description.sponsorshipThis study was performed at UNESCO-IHE Institute for Water Education with the support of Wetsus, Centre of Excellence for Sustainable Water Technology. 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 would like to thank Evides and PWN for their assistance in the sample collection, Ramesh Duraisamy for his analytical assistance and the participants of the Wetsus research theme "Biofouling" for the fruitful discussions and their financial support. We also thank the two anonymous reviewers for their constructive comments.
dc.publisherElsevier BV
dc.subjectAcid polysaccharides
dc.subjectAlgal blooms
dc.subjectAlgal organic matter
dc.subjectMembrane fouling
dc.subjectTransparent exopolymer particles (TEP)
dc.subjectWater treatment
dc.titleImproved method for measuring transparent exopolymer particles (TEP) and their precursors infresh and saline water
dc.typeArticle
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.identifier.journalWater Research
dc.contributor.institutionUNESCO-IHE Institute for Water Education, Westvest 7AX Delft, Netherlands
dc.contributor.institutionWetsus Center of Excellence for Sustainable Water Technology, Agora 1CJ Leeuwarden, Netherlands
dc.contributor.institutionDelft University of Technology, Stevinweg 1CN Delft, Netherlands
kaust.personAmy, Gary L.


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