Simple process for hardening desalinated water with Mg2+ ions

A simple easily controlled technique for adding Mg2+ ions to desalinated water is described. The Israeli Health Authority recommendation of adding of 20-30 mg/L of Mg2+ can be readily met by dissolution of magnesia pellets in a packed bed column. Experimental data are presented showing the effects of the specific flow velocity and CO2 acidification of the inlet desalinated water on the Mg2+ concentration in the product stream leaving the column. Acidification of the inlet feed water is shown to enhance considerably the dissolution process. A kinetic expression is presented enabling full design of a dissolution packed column with nonacidified water.