Impact of flow regime on pressure drop increase and biomass accumulation and morphology in membrane systems

Johannes Vrouwenvelder*, J. Buiter, M. Riviere, W. G.J. van der Meer, M. C.M. van Loosdrecht, J. C. Kruithof

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

80 Scopus citations

Abstract

Biomass accumulation and pressure drop development have been studied in membrane fouling simulators at different flow regimes. At linear flow velocities as applied in practice in spiral wound nanofiltration (NF) and reverse osmosis (RO) membranes, voluminous and filamentous biofilm structures developed in the feed spacer channel, causing a significant increase in feed channel pressure drop. Elevated shear by both single phase flow (water) and two phase flow (water with air sparging: bubble flow) caused biofilm filaments and a pressure drop increase. The amount of accumulated biomass was independent of the applied shear, depending on the substrate loading rate (product of substrate concentration and linear flow velocity) only. The biofilm streamers oscillated in the passing water. Bubble flow resulted in a more compact and less filamentous biofilm structure than single phase flow, causing a much lower pressure drop increase. The biofilm grown under low shear conditions was more easy to remove during water flushing compared to a biofilm grown under high shear. To control biofouling, biofilm structure may be adjusted using biofilm morphology engineering combined with biomass removal from membrane elements by periodic reverse flushing using modified feed spacers. Potential long and short term consequences of flow regimes on biofilm development are discussed. Flow regimes manipulate biofilm morphology affecting membrane performance, enabling new approaches to control biofouling.

Original languageEnglish (US)
Pages (from-to)689-702
Number of pages14
JournalWater Research
Volume44
Issue number3
DOIs
StatePublished - Feb 1 2010

Keywords

  • Biofilm streamers
  • Biofouling
  • Biomass cohesion strength
  • Drinking water
  • Feed spacer channel pressure drop
  • Flow regime
  • Flush
  • Linear flow velocity
  • Nanofiltration
  • Reverse osmosis
  • Shear force
  • Two phase bubble flow

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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