Abstract

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.

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Authors

Flodman HR, Dvorak BI

Institution

Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, NE 68588-0531, USA.

Source

Water environment research : a research publication of the Water Environment Federation 84:6 2012 Jun pg 535-43

MeSH

Ion Exchange
Models, Chemical
Salts
Sodium Chloride
Water
Water Pollutants, Chemical

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22866395