Waste water treatment method
First Claim
1. A method for generating fracturing water from produced water:
- transferring produced water contaminated with slick water, methanol and boron into an anaerobic pond;
holding the produced water in the anaerobic pond for at least a first mean residence time;
transferring anaerobic pond effluent to an aeration pond;
aerating the anaerobic pond effluent in the aeration pond for a second mean residence time;
transferring aeration pond effluent from the aeration pond to a solid/liquid flocculation separator; and
separating the aeration pond effluent with the solid/liquid flocculation separator to generate an aqueous effluent separated from a solids effluent;
biologically digesting the aqueous effluent in a bioreactor until a desired concentration of methanol is obtained;
transferring bioreactor effluent from the bioreactor to a reverse osmosis system;
separating contaminants from bioreactor effluent with the reverse osmosis system, the reverse osmosis system passing at least some boron in its permeate; and
removing the boron from the reverse osmosis permeate via a boron-selective removal process to obtain a desired level of boron in the reverse osmosis permeate.
11 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods have been developed for reclaiming water contaminated with the expected range of contaminants typically associated with produced water, including water contaminated with slick water, methanol and boron. The system includes anaerobically digesting the contaminated water, followed by aerating the water to enhance biological digestion. After aeration, the water is separated using a flotation operation that effectively removes the spent friction reducing agents and allows the treated water to be reclaimed and reused as fracturing water, even though it retains levels of contaminants, including boron and methanol, that would prevent its discharge to the environment under existing standards. The treated water may further be treated by removing the methanol via biological digestion in a bioreactor, separating a majority of the contaminants from the water by reverse osmosis and removing the boron that passes through the reverse osmosis system with a boron-removing ion exchange resin.
22 Citations
43 Claims
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1. A method for generating fracturing water from produced water:
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transferring produced water contaminated with slick water, methanol and boron into an anaerobic pond; holding the produced water in the anaerobic pond for at least a first mean residence time; transferring anaerobic pond effluent to an aeration pond; aerating the anaerobic pond effluent in the aeration pond for a second mean residence time; transferring aeration pond effluent from the aeration pond to a solid/liquid flocculation separator; and separating the aeration pond effluent with the solid/liquid flocculation separator to generate an aqueous effluent separated from a solids effluent; biologically digesting the aqueous effluent in a bioreactor until a desired concentration of methanol is obtained; transferring bioreactor effluent from the bioreactor to a reverse osmosis system; separating contaminants from bioreactor effluent with the reverse osmosis system, the reverse osmosis system passing at least some boron in its permeate; and removing the boron from the reverse osmosis permeate via a boron-selective removal process to obtain a desired level of boron in the reverse osmosis permeate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 11, 20)
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9. A method for generating fracturing water from produced water:
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transferring produced water contaminated with slick water, methanol and boron into an anaerobic pond; holding the produced water in the anaerobic pond for at least a first mean residence time; transferring anaerobic pond effluent to an aeration pond; aerating the anaerobic pond effluent in the aeration pond for a second mean residence time; transferring aeration pond effluent from the aeration pond to a solid/liquid flocculation clarification treatment system; floating the aeration pond effluent with the solid/liquid flocculation clarification treatment system to generate a floated aqueous effluent and a floc effluent; biologically digesting the floated aqueous effluent in a bioreactor until a desired concentration of methanol is obtained; transferring bioreactor effluent from the bioreactor to a first reverse osmosis system; separating contaminants from bioreactor effluent with the first reverse osmosis system, the first reverse osmosis system passing at least some boron in its permeate; transferring reject from the first reverse osmosis system to an electrocoagulation system; neutralizing electrostatic charges of contaminants suspended in the reject of the first reverse osmosis system to remove or destroy some of the suspended contaminants with the electrocoagulation system to generate an electrocoagulation effluent containing at least some boron; transferring at least some solids from the electrocoagulation system to an injection well; transferring the electrocoagulation effluent and the first osmosis system permeate to a second reverse osmosis system; separating contaminants from the electrocoagulation effluent with the second reverse osmosis system, the second reverse osmosis system passing at least some boron in its permeate; transferring the second reverse osmosis permeate to the boron-selective treatment system; and removing the boron from the first reverse osmosis permeate and the electrocoagulation effluent via a boron-selective removal process to obtain a desired level of boron in the first reverse osmosis permeate and the electrocoagulation effluent. - View Dependent Claims (10, 12, 13, 14, 15, 16, 17)
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18. A method for generating fracturing water from produced water:
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transferring produced water contaminated with slick water, methanol and boron into an anaerobic pond; holding the produced water in the anaerobic pond for at least a first mean residence time; transferring anaerobic pond effluent to an aeration pond; aerating the anaerobic pond effluent in the aeration pond for a second mean residence time; transferring aeration pond effluent from the aeration pond to a solid/liquid separator; and separating the aeration pond effluent with the solid/liquid separator to generate an aqueous effluent separated from a solids effluent; biologically digesting the aqueous effluent in a bioreactor until a desired concentration of methanol is obtained; transferring bioreactor effluent from the bioreactor to a reverse osmosis system; separating contaminants from bioreactor effluent with the reverse osmosis system, the reverse osmosis system passing at least some boron in its permeate; transferring reject from the reverse osmosis system to an electrocoagulation system; neutralizing electrostatic charges of contaminants suspended in the reject of the reverse osmosis system to remove or destroy some of the suspended contaminants with the electrocoagulation system to generate an electrocoagulation effluent containing at least some boron; transferring at least some solids from the electrocoagulation system to an injection well; transferring the electrocoagulation effluent to a boron-selective treatment system; transferring the reverse osmosis permeate to the boron-selective treatment system; and removing the boron from the reverse osmosis permeate and the electrocoagulation effluent via a boron-selective removal process to obtain a desired level of boron in the reverse osmosis permeate and the electrocoagulation effluent. - View Dependent Claims (19, 21, 22, 23, 24, 25, 26)
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27. A system for treating water contaminated with methanol and boron comprising:
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an anaerobic digester that receives the water and holds at least a portion of the water under anaerobic conditions; an aerator that aerates the water; a solid/liquid flocculation separator that separates contaminants from the water to produce a reclaimed water stream suitable for use as fracturing water; at least one bioreactor that biologically digests methanol in the water until a desired concentration of methanol is obtained; a boron-selective removal system that removes boron from the water until a desired concentration of boron is obtained; and at least one filtration system that removes contaminants from the water until a desired concentration of contaminants other than boron and methanol is obtained. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method for removing contaminants from produced water including boron, methanol and contaminants that inhibit the gelling of fracturing fluid when the produced water is used as fracturing water comprising:
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anaerobically digesting the produced water containing the contaminants for a first period of time; after anaerobically digesting the produced water, aerating the produced water for a second period of time; after aerating the produced water, treating the produced water in a solid/liquid flocculation separator; filtering effluent of the solid/liquid flocculation separator to generate a filtered water containing concentrations of boron and methanol; biologically digesting the filtered water, thereby reducing the concentration of methanol in the filtered water; separating contaminants from the filtered water using reverse osmosis, the reverse osmosis passing boron in its permeate and reject; and electrocoagulating the reject, the electrocoagulation effluent passing boron in its effluent; removing the boron from the reverse osmosis permeate and the electrocoagulation effluent via a boron removing ion exchange resin. - View Dependent Claims (43)
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Specification