Softener & Mixed Bed System


Derwent Water Services Limited can design and build bespoke mixed bed polishing units to suit all of our customers requirements. Cation and Anion resins are combined in a GRP or stainless steel vessel to produce ultra pure water. Usually a mixed bed polishing unit contains strong acid Cation (SAC) resin and strong base Anion (SBA) resins combined to a ratio of

approximately 40% Cation resin to 60% Anion resin. (All resin volumes are dependant upon the incoming water analysis and the required

quantity of treated water).

Mixed bed polishers are typically installed when a water quality of less than 1 micro ohm conductivity is required. Derwent Water

Services can install mixed bed polishers after a standard Reverse Osmosis or Demineraliser, to produce ultra high quality water.

The Cation resins in our mixed bed polishers are of a higher specific gravity and settle at the bottom of the vessel whilst the Anion

resin will automatically float to the top.

Please note: The Cation resin must be a strong acid Cation type (SAC) and the Anion resin must be a strong base Anion resin (SBA)

After a service cycle, each resin is regenerated as listed:

(SAC) : Strong Acid Cation resin is washed with approx. 30% hydrochloric acid.
(SBA) : Strong Base Anion is washed with approx. 26% caustic.