Brine reuse in ion-exchange softening: Salt discharge, hardness leakage, and capacity tradeoffs

Hunter R. Flodman, Bruce I. Dvorak

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Ion-exchange water softening results in the discharge of excess sodium chloride to the aquatic environment during the regeneration cycle. In order to reduce sodium chloride use and subsequent discharge from ion-exchange processes, either brine reclaim operations can be implemented or salt application during regeneration can be reduced. Both result in tradeoffs related to loss of bed volumes treated per cycle and increased hardness leakage. An experimentally validated model was used to compare concurrent water softening operations at various salt application quantities with and without the direct reuse of waste brine for treated tap water of typical midwestern water quality. Both approaches were able to reduce salt use and subsequent discharge. Reducing salt use and discharge by lowering the salt application rate during regeneration consequently increased hardness leakage and decreased treatment capacity. Single or two tank brine recycling systems are capable of reducing salt use and discharge without increasing hardness leakage, although treatment capacity is reduced.

Original languageEnglish (US)
Pages (from-to)535-543
Number of pages9
JournalWater Environment Research
Issue number6
StatePublished - Jun 2012


  • Brine
  • Ion-exchange
  • Reclaim
  • Reuse
  • Softening
  • Water

ASJC Scopus subject areas

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


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