Figure 8-1. Principles of ion-exchange processes.
In brackish waters containing essentially only calcium,
Desalination. Ion exchange can be used as a
magnesium, and alkalinity, the use of weak acid cation
desalination process in the production of potable water.
resins with degasification could be considered as a
There are several basic
possible desalination process. Since some types of
requirements for the ion-exchange process to be used
weak acid cation resins also permit the efficient removal
economically for the desalination of brackish waters.
of sodium bicarbonate, the process becomes applicable
as a desalination process when the raw water contains
mainly sodium and alkalinity.