Pretreatment of produced water to facilitate improved metal extraction

A produced water treatment method comprising:

• introducing produced water into a first vessel of a unit to subject the produced water to micro gas bubbles, the unit selected from the group consisting of flocculation, dissolved gas floatation, dissolved air floatation, induced gas floatation, froth floatation and combinations thereof to remove contaminates and concentrate metals;
• adding coagulants and pH control to precipitate magnesium and calcium compounds;
• removing magnesium and calcium compounds;
• introducing the produced water particular microorganisms into a second vessel of a moving bed biofilm reactor to be disposed on carriers in the second vessel;
• introducing nutrients into the second vessel for the microorganisms;
• concurrently subjecting produced water that includes organic materials therein, in a vessel, to:
• a biological water treatment process that removes aqueous phase organic materials from the produced water using microorganisms circulating in the produced water on carriers;
• and
• a physical water treatment process that removes non-aqueous phase liquid organic materials or volatile phase organic materials from the produced water, wherein the physical water treatment process comprises:
• sparging a gas through the produced water, the sparging of the gas causing (a) a coalescing of the non-aqueous phase liquid organic materials so that the non-aqueous phase liquid organic materials settle on a surface of the produced water or (b) vapor stripping of the volatile phase organic materials so that the volatile phase organic materials move to a location above the surface of the produced water.

A produced water treatment system comprising:

• a first vessel comprising a unit to subject the produced water to micro gas bubbles, the unit selected from the group consisting of flocculation, dissolved gas floatation, dissolved air floatation, induced gas floatation, froth floatation and combinations thereof to remove contaminates and concentrate metals;
• a first device for adding coagulants and pH control to precipitate magnesium and calcium compounds;
• a second device for removal of magnesium and calcium compounds;
• a second vessel adapted to concurrently remove organic materials from the produced water by (1) a first biological water treatment process and (2) a first physical separation process, the second vessel comprising:
• a biological removal system comprising microorganisms for removing a first set of organic materials from the produced water;
• and
• a physical separation system comprising sparging equipment for sparging the produced water to remove a second set of organic materials from the produced water.