Chlorination-assisted coagulation processes and systems are disclosed for removing organic and inorganic contaminants from aqueous compositions and streams such as produced water generated by petroleum production operations. The chlorination-assisted coagulation process includes converting at least a portion of chloride ions in the aqueous composition to hypochlorite ions or hypochlorous acid by passing an electric current through at least a portion of the aqueous composition under anaerobic conditions, the aqueous composition including the chloride ions, iron (II) compounds, and one or more organic compounds. The chlorination-assisted coagulation process further includes reacting at least a portion of the iron (II) compounds of the aqueous composition with the hypochlorite or hypochlorous acid to produce iron (III) ions, and coagulating the one or more organic compounds with the iron (III) ions to produce a plurality of insoluble solid particles in a treated aqueous composition.