Rapid sand filtration pretreatment for SWRO: Microbial maturation dynamics and filtration efficiency of organic matter

Edo Bar-Zeev, Natalia Belkin, Boris Liberman, Tom Berman, Ilana Berman-Frank

Research output: Contribution to journalArticlepeer-review

Abstract

Rapid sand filtration (RSF) is used today as an effective pretreatment procedure to enhance water quality prior to reverse osmosis (RO) membranes in desalination plants. RSF in newly operated desalination facilities requires a maturation period of about three months before the feedwater may be filtered efficiently. To date the desalination industry RSF has regarded RSF mainly as a physical barrier effectively retaining particles larger than 0.35. mm. In this study we assessed the potential of the RSF as a biological filter by following the dynamics of bacterial colonization and metabolic activity within the filter bed and determining filtration efficiency in respect to particulate and dissolved organic carbon, chlorophyll a and transparent exopolymeric particles (TEP). Bacterial abundance and diversity were shown by DGGE and SEM analysis to increase gradually over a three month sampling period. Bacterial metabolic activity within the filter bed interstitial water increased erratically with time. With the outgrowth of a microbial population and biofilm development on the filter bed medium, significant removal of organic carbon from the source water was always observed. Our results indicate that current RSFs function as biofilters with moderate efficiency. Innovative design is needed to maximize the biofiltration potential of these filters.

Original languageEnglish
Pages (from-to)120-130
Number of pages11
JournalDesalination
Volume286
DOIs
StatePublished - 1 Feb 2012
Externally publishedYes

Bibliographical note

Funding Information:
We thank I.D.E. for partial funding and for access to the Hadera desalination Plant. We also thank Niv Schechter for assistance in sampling and SEM analysis. This research is part of the MSc (Natalia Belkin) and PhD (Edo Bar-Zeev) requirements at Bar Ilan University. Edo Bar Zeev is supported by a President's Scholarship from Bar Ilan University .

Keywords

  • Biodegradation
  • Biofilm
  • Filtration efficiency
  • Maturation period
  • Rapid sand filtration
  • SWRO pretreatment

ASJC Scopus subject areas

  • Chemistry (all)
  • Chemical Engineering (all)
  • Materials Science (all)
  • Water Science and Technology
  • Mechanical Engineering

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