Patent ID: 8858802

Claim:
A method for treating produce water from a steam assisted gravity drainage (SAGD) operation, said method comprising the steps of: a) adjusting said produce water to a pH of about 2 to 8; b) after said step a), adding a tannin coagulant to said produce water; c) after said step b), adjusting pH of said produce water to between about 6.5 to 10; and d) adding to said produce water from step c) a cationic flocculant and an anionic flocculant, said cationic flocculant comprising a member selected from the group consisting of an acrylamide/quaternary ammonium salt copolymer, a copolymer of epichlorohydrin and amine, an acrylamide allyl trialkyl ammonium copolymer, and acrylamide/diallyl dialkyl ammonium copolymer, said anionic flocculant comprising a member selected from the group consisting of acrylamide/acrylic acid copolymers and salts thereof, acrylamide alkylacrylate copolymers, acrylamide/maleic acid copolymers, acrylamide maleic anhydride copolymers, acrylamide/(AMPS) copolymers, acrylic acid homopolymers and salts thereof, and acrylic acid (AMPS) copolymers.