Nitrate removal by
Purolite® ion exchange is accomplished with
Purolite SBA resins, which are brine regenerated.
Purolite SBA resins exchange the nitrate ion for the chloride ion.
The
Purolite® SBA resins of choice are:
A300
A400
A520E
A600
These
Purolite® resins can be used in separate vessels, or they may be top dressed on the cation resin bed within a mixed resin bed system, where it is recommended that a minimum 15cm or 6"
Purolite® Nitrate removal resin bed be top dressed. This can be successful when the water Hardness is less than 170 mg/l or 10 gpg.
Since the Nitrate removing
Purolite® resin is lighter in specific gravity than the
Purolite® cation resin, adjustment must be made to the backwash flow rate of the mixed bed, which should be reduced by 30 -50% while doubling the backwash time. In addition, an upper strainer basket should be installed on the inlet of the vessel to prevent resin loss during backwash.