The invention relates to a process for treating unwanted moderately
saline waters for producing waters acceptable for treating soil, such as for
irrigation. The
treated water is also suitable for human and
livestock consumption. The process includes passing moderately
saline waters having 0.05% or more by weight and less than 1.00% by weight of the salts of Na, K, Ca, Mg, Fe, Cl, SO4, or CO3 or combinations thereof through an
ion exchange resin. The
ion exchange resin is pre-treated to be saturated with multivalent cations. Preferred multivalent cations include
calcium (Ca2+) or
magnesium (Mg2+) ions, or combinations thereof. After passing through the
ion exchange resin, the
effluent has
decreased sodium cations and
increased calcium and / or
magnesium cations compared to the pre-treated moderately
saline water. As the moderately saline waters passes through the
ion exchange resin, the
sodium content of the resin rises as the multivalent cation content lowers until the resin is unacceptable for further
water treatment in accordance with the present invention. To regenerate the
ion exchange resin, the resin is flushed with a brine solution having more than 1.00% by weight of the salts of Na, K, Ca, Mg, Fe, Cl, SO4, or CO3. Preferably, the brine is particularly high in
calcium and / or
magnesium content and low in
sodium. The brine solution is flushed through the
ion exchange resin until the
ion exchange resin is sufficiently saturated with multivalent cations to again process moderately
saline water having
high sodium content.