Water softening deals with domestic as well as industrial water softening. It is a straight forward process, which utilises ion exchange resins to reduce the concentration of those ionic species which can cause scaling and insolubility problems in the everyday uses of water. This is called the removal of hardness.
In domestic environments, Purolite^® Ion Exchange Resins are used to soften water for use in appliances such as washing machines, dishwashers and steam irons. Purolite water softening resins are also found in filters used for purification of drinking water, and throw away cartridges. In an industrial context, water softening is used in laundries, in brewing and soft drink manufacture for bottle washing, process water for LP boilers, and process water for industrial and chemical processes which require softened water e.g. textiles.

A variety of Purolite^® Ion Exchange resins can be used for this type of application. In general, softening is the removal of Calcium and Magnesium, referred to as total hardness, from a water supply. Major factors in the water supply that affect the performance of the resin are:

• Iron and Manganese content
• Chlorine content
• TDS
• Water temperature
• Flow rates
• Heavy metal content
• Sodium content

The Sodium or Potassium ion is exchanged for the Hardness ions. The type of resin used is a Purolite^® Strong Acid Cation (SAC) resin, typically regenerated with Sodium or Potassium Chloride. With high TDS or hardness levels, the Purolite SAC resin is sometimes preceded by a Purolite Weak Acid Cation (WAC) resin.

With water of high temperature, iron or chlorine content softening is also accomplished with Purolite Macroporous SAC resins.

The Purolite^® Water Softening resins of choice typically are C100 type, C150 type, or Purolite SST (Salt Saving Technology) grades e.g. SST60

It is sometimes preferred to use a Purolite^® resin that is more efficient in its operation than the standard resins discussed previously. Among these Purolite resins would be:

• A Uniform Particle Size resin such as  Purolite^®PPC100E or C100E which are more efficiently regenerated.
• A Fine Mesh resin such as Purolite^® PFC100, or C100EFM which are more efficiently regenerated and capable of handling higher concentrations of Iron (both Ferrous and Ferric).
• A Shallow Shell Technology resin Purolite^®SST60, which offers high capacity at low salt dosage and low hardness leakage at lower salt dosage than standard Purolite SAC resins without the higher pressure drop experienced with Purolite Fine Mesh resins.
  
  

  The top water softening experts in the world lead by Purolite's Chubb Michaud, has written a Water Softening Basics Overview to help you with your water softening needs. 

For a review of our range of Purolite^® Ion Exchange Resins engineered for Water Softening, please see our Characteristics & Applications Summary Brochure.