Method for Treating Wastewater or Produced Water
First Claim
1. A method for treating produced water derived from an oil recovery operation and containing contaminants such as organics, silica, boron, hardness, dissolved solids, and suspended solids, the method comprising:
- a. chemically softening the produced water in a series of reactors by;
i. in one reactor mixing a coagulant with the produced water and destabilizing solids contained within the produced water;
ii. in one reactor mixing lime with the produced water, and converting carbon dioxide to bicarbonate ions and neutralizing bicarbonate alkalinity;
iii. in one reactor mixing a caustic with the produced water and wherein the lime and caustic cause the pH of the produced water to be raised above 10.5;
iv. in one reactor mixing a polymer with the produced water to facilitate separation of solids in the produced water;
v. clarifying the produced water by separating sludge from the produced water; and
,vi. directing at least a portion of the sludge to at least one reactor and mixing the sludge with the produced water;
b. after chemically softening, filtering the produced water with a multimedia filtration unit to further separate contaminants from the produced water to produce filtered produced water and a first waste stream;
c. recycling at least a portion of first waste stream to at least one of the reactors;
d. after filtering the produced water with the multimedia filter, further softening the produced water by directing the produced water through an ion exchange softening unit wherein calcium and magnesium ions are displaced by sodium ions supplied by an added chemical, producing further softened produced water and a second waste stream;
e. recycling at least a portion of the second waste stream;
f. after ion exchange softening, directing the produced water though a cartridge filtration unit to further separate contaminants from the produced water; and
g. directing produced water from the cartridge filtration unit to at least one reverse osmosis unit and removing organics, boron, silica and dissolved solids from the produced water and producing product water.
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Accused Products
Abstract
A method or process for treating wastewater containing high organics, silica, boron, hardness, and suspended and dissolved solids. The method includes degasifying the wastewater for the removal of dissolved gases and thereafter chemically softening the wastewater. After the chemical softening step, the wastewater is directed through a media filter or membrane which removes additional solids and precipitants. Thereafter the wastewater is directed through a sodium ion exchange that further softens the wastewater. The effluent from the ion exchange is directed through a cartridge filter and the effluent from the cartridge filter is directed through one or more reverse osmosis units. At a selected phase of the process, prior to the wastewater reaching the reverse osmosis unit or units, the pH of the wastewater is raised and maintained such that the pH of the wastewater reaching a reverse osmosis unit is at a pH greater than 10.5.
59 Citations
45 Claims
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1. A method for treating produced water derived from an oil recovery operation and containing contaminants such as organics, silica, boron, hardness, dissolved solids, and suspended solids, the method comprising:
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a. chemically softening the produced water in a series of reactors by; i. in one reactor mixing a coagulant with the produced water and destabilizing solids contained within the produced water; ii. in one reactor mixing lime with the produced water, and converting carbon dioxide to bicarbonate ions and neutralizing bicarbonate alkalinity; iii. in one reactor mixing a caustic with the produced water and wherein the lime and caustic cause the pH of the produced water to be raised above 10.5; iv. in one reactor mixing a polymer with the produced water to facilitate separation of solids in the produced water; v. clarifying the produced water by separating sludge from the produced water; and
,vi. directing at least a portion of the sludge to at least one reactor and mixing the sludge with the produced water; b. after chemically softening, filtering the produced water with a multimedia filtration unit to further separate contaminants from the produced water to produce filtered produced water and a first waste stream; c. recycling at least a portion of first waste stream to at least one of the reactors; d. after filtering the produced water with the multimedia filter, further softening the produced water by directing the produced water through an ion exchange softening unit wherein calcium and magnesium ions are displaced by sodium ions supplied by an added chemical, producing further softened produced water and a second waste stream; e. recycling at least a portion of the second waste stream; f. after ion exchange softening, directing the produced water though a cartridge filtration unit to further separate contaminants from the produced water; and g. directing produced water from the cartridge filtration unit to at least one reverse osmosis unit and removing organics, boron, silica and dissolved solids from the produced water and producing product water. - View Dependent Claims (2, 3, 4, 5, 6, 8, 10, 12)
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- 7. The method of claim l wherein chemical softening includes a phase in which the produced water is mixed utilizing a draft tube type mixer giving rise to crystallization and densification of solids contained in the produced water.
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11. The method of claim I wherein a second coagulant is injected into the produced water after the produced water has been clarified and before the produced water is subjected to multimedia filtration.
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13. A method for treating produced water derived from an oil recovery operation and containing contaminants such as organics, silica, boron, hardness, dissolved solids, and suspended solids comprising:
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a. chemically softening the produced water by; i. mixing a coagulant, at least one alkaline reagent, and a flocculant with the produced water; ii. raising the pH of the produced water to greater than 10.5; iii. clarifying the produced water by separating sludge which includes suspended solids and precipitants from the produced water; and iv. returning at least a portion of the sludge and mixing it with the produced water; b. after chemically softening the produced water, subjecting the produced water to filtration and further removing solids; c. after chemically softening the produced water, subjecting the produced water to ion exchange and further softening the produced water; and d. after filtering and further softening, directing the produced water through at least one reverse osmosis unit and removing boron, silica, organics and dissolved solids and generating product water. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of softening wastewater and conditioning the wastewater for further treatment, comprising:
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a. chemically softening the wastewater by directing the wastewater through a chemical softening system having a series of reactors and a clarifier; b. mixing a coagulant with the wastewater in one of the reactors and destabilizing solids in the wastewater; c. mixing at least two alkaline reagents in the wastewater in one or more of the reactors to precipitate contaminants that give rise to hardness in the wastewater and to raise the pH of the wastewater to above 10.5; d. mixing a flocculent with the wastewater in one or more of the reactors; e. clarifying the wastewater in the clarifier to produce a clarified effluent and sludge; f. recycling at least a portion of the sludge to at least a portion of the chemical softening system; g. directing the clarified effluent from the chemical softening system to a filtering unit and filtering the clarified effluent; and h. directing the effluent from the filter unit to at least one ion exchange unit and softening the effluent from the filter unit. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A method for treating wastewater containing contaminants such as organics, silica, boron, hardness, dissolved solids, and suspended solids, the method comprising:
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a. chemically softening the wastewater in a series of reactors by; i. in one reactor mixing a coagulant with the wastewater and destabilizing solids contained within the wastewater; ii. in one reactor mixing lime with the wastewater, and converting carbon dioxide to bicarbonate ions and neutralizing bicarbonate alkalinity; iii. in one reactor mixing a caustic with the wastewater and wherein the lime and caustic cause the pH of the wastewater to be raised above 10.5; iv. in one reactor mixing a polymer with the wastewater to facilitate separation of solids in the wastewater; v. clarifying the produced water by separating sludge from the wastewater; and
,vi. directing at least a portion of the sludge to at least one reactor and mixing the sludge with the wastewater; b. after chemically softening, filtering the wastewater with a multimedia filtration unit to further separate contaminants from the wastewater to produce filtered wastewater and a first waste stream; c. recycling at least a portion of first waste stream to at least one of the reactors; d. after filtering the wastewater with the multimedia filter, further softening the wastewater by directing the wastewater through an ion exchange softening unit wherein calcium and magnesium ions are displaced by sodium ions supplied by an added chemical, producing further softened wastewater and a second waste stream; e. recycling at least a portion of the second waste stream; f. after ion exchange softening, directing the wastewater though a cartridge filtration unit to further separate contaminants from the wastewater; and g. directing wastewater from the cartridge filtration unit to at least one reverse osmosis unit and removing organics, boron, silica and dissolved solids from the wastewater and producing product water. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification