Methods of separating water, salt, CO2, and crude oil from wastewater, the methods comprising: providing gas/oil separation system that produces a waste saline water stream and a CO2 stream; providing an electrochemical cell having an anode, a cathode, and three electrodialytic compartments; feeding a fresh water stream to the anode to produce H+ and O2; feeding the waste CO2 stream and O2 to the cathode to produce bicarbonate (HCO3—) and hydronium ions (H+); feeding the waste saline water stream to the center electrodialytic compartment; wherein the sodium (Na) from the waste saline water stream reacts with the bicarbonate to form NaHCO3 and the chlorine (Cl) from the waste saline water stream reacts with the hydroxide to produce hydrochloric acid the saline wastewater and the treated CO2 into an electrochemical cell; and producing salt and desalinated water.