Methods and systems for producing treated brines

Abstract

Water treatment systems and associated methods are generally described. Certain embodiments of the water treatment systems and methods described herein may be used to treat water comprising one or more contaminants (e.g., oil, grease, suspended solids, scale-forming ions, volatile organic material) to remove at least a portion of the one or more contaminants. In some embodiments, at least a portion of the treated water may be used directly in certain applications (e.g., oil and/or gas extraction processes). In some embodiments, at least a portion of the treated water may undergo desalination to produce substantially pure water and/or concentrated brine.

What is claimed is: 
     
         1 - 31 . (canceled) 
     
     
         32 . A method for treating water, comprising:
 supplying an aqueous input stream to an induced gas flotation (IGF) separator;   removing, within the IGF separator, at least a portion of at least one suspended and/or emulsified immiscible phase from the aqueous input stream to produce an immiscible-phase-diminished stream containing less of the immiscible phase relative to the aqueous input stream;   removing at least a portion of at least one scale-forming ion from a quantity of the immiscible-phase-diminished stream using caustic soda (NaOH), soda ash, and a flocculent to produce an ion-diminished stream containing less of the at least one scale-forming ion relative to the immiscible-phase-diminished stream, wherein the removing at least a portion of at least one scale-forming ion from the quantity of the immiscible-phase-diminished stream comprises:
 adding, within a first tank, the caustic soda to at least a portion of the quantity of the immiscible-phase-diminished stream and producing a stream effluent from the first tank; 
 adding, within a second tank, the soda ash to at least a portion of the stream effluent from the first tank and producing a stream effluent from the second tank; and 
 adding, within a third tank, the flocculent to at least a portion of the stream effluent from the second tank to produce the ion-diminished stream; and 
   directing at least a portion of the ion-diminished stream to a storage tank.   
     
     
         33 . The method for treating water according to  claim 32 , wherein the directing step involves directing at least a portion of the ion-diminished stream to the storage tank without first directing the portion of the ion-diminished stream to any crystallization tank. 
     
     
         34 . The method for treating water according to  claim 32 , wherein the directing step involves directing at least a portion of the ion-diminished stream to the storage tank without first directing the portion of the ion-diminished stream to any humidifier or dehumidifier apparatus. 
     
     
         35 . The method for treating water according to  claim 32 , wherein the IGF separator is configured to remove droplets of the immiscible phase having an average droplet size of at least about 20 microns. 
     
     
         36 . The method for treating water according to  claim 32 , wherein the immiscible phase comprises oil and/or grease. 
     
     
         37 . The method for treating water according to  claim 32 , wherein the removing at least a portion of at least one scale-forming ion comprises removing at least about 5% of the scale-forming ion from the immiscible-phase-diminished stream. 
     
     
         38 . The method for treating water according to  claim 32 , wherein the ion-diminished stream contains scale-forming ions in an amount of about 5000 mg/L or less. 
     
     
         39 . The method for treating water according  claim 32 , further comprising a step of increasing or decreasing the pH of the aqueous input stream, the immiscible-phase-diminished stream, and/or the ion-diminished stream to produce at least one pH-adjusted stream. 
     
     
         40 . The method for treating water according to  claim 39 , further comprising a step of removing at least a portion of volatile organic material (VOM) from the aqueous input stream, the immiscible-phase-diminished stream, the ion-diminished stream, and/or the at least one pH-adjusted stream to produce at least one VOM-diminished stream. 
     
     
         41 . The method for treating water according to  claim 40 , further comprising a step of passing the aqueous input stream, the immiscible-phase-diminished stream, the ion-diminished stream, the at least one pH-adjusted stream, and/or at the least one VOM-diminished stream through a filtration apparatus. 
     
     
         42 . The method for treating water according to  claim 41 , wherein the filtration apparatus comprises a filter press. 
     
     
         43 . The method for treating water according to  claim 32 , further comprising a step of removing at least a portion of VOM from the aqueous input stream, the immiscible-phase-diminished stream, and/or the ion-diminished stream to produce at least one VOM-diminished stream. 
     
     
         44 . The method for treating water according to  claim 32 , wherein the IGF separator is an induced air flotation (IAF) separator. 
     
     
         45 . The method for treating water according to  claim 32 , wherein the flocculent comprises ferric chloride, polyaluminum chloride, activated silica, colloidal clay, a metallic hydroxide with a polymeric structure, a starch, a starch derivative, a polysaccharide, an alginate, a polyacrylamide, a polyethylene-imine, a polyamide-amine, a polyamine, a polyethylene oxide, and/or a sulfonated compound. 
     
     
         46 . The method for treating water according to  claim 32 , wherein the flocculent comprises a polymer. 
     
     
         47 . The method for treating water according to  claim 32 , wherein the flocculent comprises an anionic polymer flocculent. 
     
     
         48 . The method for treating water according to  claim 32 , wherein:
 the immiscible-phase-diminished stream is a first immiscible-phase-diminished stream;   the removing, within the IGF separator, at least a portion of at least one suspended and/or emulsified immiscible phase from the aqueous input stream also produces an immiscible-phase-enriched stream; and   the method further comprises:
 removing, within a secondary separator, at least a portion of at least one suspended and/or emulsified immiscible phase from the immiscible-phase-enriched stream to produce a second immiscible-phase-diminished stream containing less of the immiscible phase relative to the immiscible-phase-enriched stream; 
 removing at least a portion of at least one scale-forming ion from a quantity of the second immiscible-phase-diminished stream using caustic soda (NaOH), soda ash, and a flocculent to produce the ion-diminished stream, the ion-diminished stream containing less of the at least one scale-forming ion relative to the second immiscible-phase-diminished stream, wherein the removing at least a portion of the at least one scale-forming ion from the quantity of the second immiscible-phase-diminished stream comprises:
 adding, within the first tank, the caustic soda to at least a portion of the quantity of the second immiscible-phase-diminished stream and producing the stream effluent from the first tank; 
 adding, within the second tank, the soda ash to at least a portion of the stream effluent from the first tank and producing a stream effluent from the second tank; and 
 adding, within the third tank, the flocculent to at least a portion of the stream effluent from the second tank to produce the ion-diminished stream. 
 
   
     
     
         49 . The method for treating water according to  claim 48 , wherein the immiscible-phase-enriched stream has a residence time in the secondary separator of at least 5 minutes. 
     
     
         50 . The method for treating water according to  claim 32 , wherein the aqueous stream has a residence time in the IGF separator of less than or equal to 30 minutes. 
     
     
         51 . The method for treating water according to  claim 32 , further comprising directing at least a portion of the ion-diminished stream from the storage tank to a humidifier.