Christensen, Morten Lykkegaard

Keiding, Kristian

Poorasgari, Eskandar

English

    Aalborg UniversitetAdsorption of EPS on PVDF microfilters and its relationship with permeability declinePoorasgari, Eskandar; Christensen, Morten Lykkegaard; Keiding, KristianPublication date:2012Document VersionEarly version, also known as pre-printLink to publication from Aalborg UniversityCitation for published version (APA):Poorasgari, E., Christensen, M. L., & Keiding, K. (2012). Adsorption of EPS on PVDF microfilters and itsrelationship with permeability decline. Poster presented at Nordic Filtration Symposium, Aalborg, Denmark.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: December 25, 2020Results Adsorption of EPS on PVDF micro-filters and its relationship with permeability decline Eskandar Poorasgari*, Morten Lykkegaard Christensen, Kristian Keiding   Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark. * E-mail: esp@bio.aau.dk  INTRODUCTION CONCLUSIONS www.ecodesign.aau.dk EXPERIMENTAL SET-UP 1. Developing a robust method for extraction of LBEPS.  2. Developing a reproducible method for permeability measurements.  3. Developing method for testing adsorption of LBEPS on membranes.  4. Finding correlation between adsorption kinetics and permeability decline. Exposing of LBEPS to the PVDF micro-filters reduced  the membrane permeability to 50%.  www.chemistry.aau.dk Blue columns: before contact to LBEPS Red columns: after contact to LBEPS Adsorption  setup Membrane disc Magnetic stirrer Stir bar Aims Figure 1: Effect of 9 h exposure at 20̊ C to LBEPS on membrane permeability.   Figure 1 shows that the three  PVDF MF discs have different initial permeability, but after exposing to LBEPS, permeability of all of them  declined and three membrane discs showed similar permeabilities. before exposing to LBEPS after exposing to LBEPS Permeability  setup Pressurized clean water tank Pressure gauge Membrane Permeate vessel Balance Adsorption cell  containng LBEPS Figure 2: Effects of 67 h exposure to LBEPS on membrane permeability.  The experiment in figure 2 was done at 4̊ C so there was no biological growth and permeability decline is ascribed  to inter-molecular affinity between the membrane active surface and the LBEPS components. Materials and methods   LBEPS extracted from MBR sludge by centrifugation and ultrasonication.  The extracted LBEPS was characterised. It consist of 150 mg/L protein, 20 mg/L humic substances (modified Lowry method), and 70 mg/L carbohydrates (Anthrone method)  The prepared LBEBS solution was in contact with polyvynilidene fluoride (PVDF) microfilters (Alfalaval CO.) for several hours. See adsorption set-up.  Membrane permeability was measured  before and after contact of membrane with the LBEPS solution by using the permeability set-up.    Membrane fouling is deposition of substances on the membrane surface or within its pores, and it lowers the permeability.   One of the fouling mechanisms is adsorption. Adsorption of materials on the membrane surface 1) lowers the permeability, 2) change the surface of the membrane, and 3) increase the need for membrane cleaning.  Organics often adsorp to membrane and different authors have reported that extracellular polymeric substances (EPS) is one of the main causes of fouling in MBR systems.   Different EPS fractions exist in wastewater 1) dissolved EPS also called Soluble microbial produced (SMP), 2) EPS loosely-bound to the flocs (LBEPS) and 3) EPS tigthly bound to the flocs (TBEPS).   The idea of this work is to study how Loosely-bound extra-cellular polymeric substances (LBEPS) are present in the outer regions  of  sludge aggregates, and they are in contact with the membranes of the membrane bio-reactors (MBRs).  

Adsorption of EPS on PVDF microfilters and its relationship with permeability decline

https://vbn.aau.dk/ws/files/74247215/NoFS_2012_Poster_ESP.pdf

Adsorption of EPS on PVDF microfilters and its relationship with permeability decline

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