Patent ID: 7320756

Claim:
A process for treatment of a feedwater stream in reverse osmosis membrane separation equipment, said reverse osmosis membrane separation equipment comprising at least one unit having a reverse osmosis membrane separator, to produce a low solute containing product stream and a high solute containing reject stream, said process comprising: (a) providing a feedwater stream containing carbon dioxide and/or solutes therein, said solutes comprising cations; (b) pretreating said feedwater stream by controlling the pH to about 4.3 or lower, to assure at least some free mineral acidity in the pretreated feedwater at the point of feed to said reverse osmosis membrane separation equipment, without (i) removal of substantially all cations present in said feedwater stream, or (ii) removal of carbon dioxide; (c) passing the resultant pretreated feedwater through said reverse osmosis membrane separation equipment, said reverse osmosis membrane separation equipment substantially resisting passage of at least some dissolved species therethrough, to concentrate said pretreated feedwater to said preselected concentration factor, to produce (i) a high solute containing reject stream, and (ii) a low solute containing product stream; (d) wherein feedwater stream comprises a total organic carbon (TOC) constituent, and wherein said total organic carbon (TOC) constituent is effectively removed from said product stream; and (e) wherein said total organic carbon (TOC) constituent comprises one or more nonionizable species, and wherein said one or more non-ionizable species are selected from the group consisting of (a) isopropyl alcohol, and (b) acetone.