Patent ID: 7815804
Filing Date: 2010-10-19
Classification: B01D,C02F

Abstract:
1. A method for treating produced water derived from an oil recovery operation and containing contaminants including organics, silica, hardness, dissolved solids, and suspended solids, the method comprising: a. removing hardness from the produced water by chemically softening the produced water in a series of reactors by: b. after chemically softening, filtering the produced water with a multimedia filtration unit to further separate suspended solids from the produced water to produce filtered produced water and a first waste stream; c. recycling at least a portion of first waste stream to at least one of the reactors; d. after filtering the produced water with the multimedia filter, further softening the produced water by directing the produced water through an ion exchange softening unit wherein calcium and magnesium ions are displaced by sodium ions supplied by an added chemical, producing further softened produced water and a second waste stream; e. recycling at least a portion of the second waste stream to at least one reactor; f. after ion exchange softening, directing the produced water though a cartridge filtration unit to further separate contaminants from the produced water; and g. directing produced water at said pH from the cartridge filtration unit to at least one reverse osmosis unit and removing organics, boron, silica and dissolved solids from the produced water and producing product water.