Methods of separating and isolating water and other desired constituents from oilfield produced brines for reuse

A method of processing hydrocarbon produced water, the method comprising:

• deoiling the hydrocarbon produced water to provide a deoiled feed stream;
• introducing an electrolysis cell-provided oxidant to the deoiled feed stream to provide an oxidized feed stream;
• precipitating the oxidized feed stream to provide a precipitated slurry;
• passing the precipitated slurry through a tubular membrane filter unit to produce a permeate;
• reducing the pH of the permeate to provide a reduced pH permeate;
• passing the reduced pH permeate through a nanofiltration membrane unit to produce a NF permeate and a NF reject;
• passing the NF permeate to said electrolysis cell, to a freshwater- and concentrated sodium chloride retentate-providing seawater reverse osmosis membrane, or to both the electrolysis cell and the seawater reverse osmosis membrane;
• passing the concentrated sodium chloride retentate to an electrodialysis device including univalent anion and univalent cation membranes and electrodes to produce a diluate depleted in sodium chloride and a sodium chloride concentrate;
• passing the diluate to the nanofiltration membrane unit;
• passing at least a portion of the sodium chloride concentrate to a bipolar membrane electrodialysis unit, to the electrolysis cell, or to both the bipolar membrane electrodialysis unit and the electrolysis cell;
• and
• generating a hydrochloric acid stream and a sodium hydroxide stream from the bipolar membrane electrodialysis unit.