Patent ID: 8758720

Claim:
A composition matter consisting essentially of water and dissolved solutes, (a) said composition of matter being the product water resulting from the treatment of a feedwater stream in a first reverse osmosis membrane separation unit that produces a product water stream low in solutes and a reject stream high in solutes; (b) wherein said process comprises: (1) providing a feedwater stream containing solutes therein, said solutes comprising total dissolved solids (TDS), including (i) hardness, (ii) alkalinity, and (iii) at least one molecular species which is sparingly ionized when in neutral or near neutral pH aqueous solution; (2) effectively eliminating the tendency of said feedwater to form scale when said feedwater is concentrated at a selected pH of at least 9 to a preselected concentration factor in a first pass membrane separator unit, by effecting before concentration (i) removal of hardness from said feedwater stream; removal of substantially all alkalinity associated with hardness from said feedwater stream; and (iii) removing dissolved gas from said feedwater stream, whether initially present or created during said hardness removal or said alkalinity removal; (3) raising the pH of the pretreated feedwater stream to a selected pH of at least about 9 to urge said at least one molecular species which is sparingly ionized when in neutral or near neutral pH aqueous solution toward increased ionization; and (4) passing the pH adjusted pretreated feedwater stream through said first reverse osmosis membrane separation unit, said first reverse osmosis membrane unit operated at the selected pH so that it substantially resists passage of dissolved species therethrough, to concentrate said feedwater to said preselected concentration factor and to produce a low solute containing product water stream and a high solute containing reject stream; (c) said product water characterized in that has a pH greater than 9, and it comprises sodium (as ion), calcium (as ion) in an amount of less than 0.003 parts per million, and silica (as silica) in an amount of 0.46 parts per million or less, and wherein the ratio of sodium (as ions) to total dissolved solids (TDS) is about two thirds, or higher.