Controlling scaling in membrane filtration systems using a desupersaturation unit

I. Bremere*, M. Kennedy, P. Michel, R. van Emmerik, Geert-Jan Witkamp, J. Schippers

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

38 Scopus citations

Abstract

Scaling in reverse osmosis (RO) and nanofiltration (NF) systems is generally controlled by limiting the conversion and/or the addition of antiscalants. An alternative approach might be the desupersaturation of membrane concentrate before e.g. the last stage of an RO and/or NF system. A desupersaturation unit (DU) is aimed at reducing the degree of supersaturation in membrane concentrate stream by forced precipitation of sparingly soluble inorganic compounds on seed crystals. Barium sulfate precipitation was examined in a laboratory scale (DU) using supersaturated synthetic (no organic matter) and natural RO and NF concentrates. Effective barium removal for at least 100 h was observed in the case of synthetic concentrate. Early breakthrough of barium sulfate crystallization occurred in NF concentrate. This was attributed to the adsorption of organic matter (TOC = 22 mg/l) and subsequent poisoning of barium sulfate seed crystals. Two RO concentrates from surface water treatment pilot plants were compared. Barium sulfate removal was not affected (100 h) by organic matter (TOC = 12 mg/l) in River Rhine water pretreated by ultrafiltration. However, break-through was observed from River Rhine water with organic matter (TOC = 8 mg/l) pretreated by ozonation. Irreversible poisoning of seed crystals was attributed to adsorption of organic compounds, e.g. low molar mass acids produced by ozone pretreatment of RO feedwater. Inactivated barium sulfate crystals were restored by backwashing with acidified (pH = 2) water.

Original languageEnglish (US)
Pages (from-to)51-62
Number of pages12
JournalDesalination
Volume124
Issue number1-3
DOIs
StatePublished - Nov 1 1999
EventProceedings of the 1999 European Conference on Desalination and the Environment - Las Palmas, Spain
Duration: Nov 9 1999Nov 12 1999

Keywords

  • Barium sulfate
  • Desupersaturation
  • Nanofiltration
  • Organic matter
  • Reverse osmosis
  • Scaling control

ASJC Scopus subject areas

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

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