This application pertains to those waters where high sulfates (>250 ppm) are to be removed by Purolite^® ion exchange. High levels of sulfates have been known to cause diarrhea in humans and animals. Purolite Strong Base Anion (SBA) exchange resins, operated in the chloride form, can remove these sulfate ions.

In addition, high sulfate levels are also a concern for Reverse Osmosis (RO) membrane fouling. At high concentrations, they precipitate on the membranes and reduce the efficiency.

The Purolite Strong Base Anion resins of choice for non-potable applications, such as RO pretreatment in industrial applications, are:

A300
A400
A500
A600

These Purolite® resins are regenerated with brine. As Purolite anion resins, they use the chloride portion of the NaCl. During the service run the sulfate ions displace the chloride ions due to the higher selectivity of the Purolite Strong Base resins towards sulphate ions.

If a water softening control is used for the sulfate removal process, adjustment must be made to the backwash flow rate by a reduction of 30-50%, and the backwash time doubled. In addition, an upper strainer basket should be installed on the inlet of the vessel to prevent resin loss during backwash.

For capacity calculations see the appropriate Purolite Technical Data Sheet.

Where Total Hardness of the water to be treated exceeds 170 mg/l or 10 gpg it is recommended to pretreat by softening.