Method for treating wastewater or produced water
DCFirst Claim
1. A method for treating produced water derived from an oil recovery operation and containing contaminants including organics, silica, hardness, dissolved solids, and suspended solids, the method comprising:
- a. removing hardness from the produced water by 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 to remove calcium carbonate hardness;
iii. in one reactor mixing a caustic with the produced water to remove magnesium hardness 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 suspended solids 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 to at least one reactor;
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 at said pH 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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Litigations
1 Petition
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.
81 Citations
27 Claims
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1. A method for treating produced water derived from an oil recovery operation and containing contaminants including organics, silica, hardness, dissolved solids, and suspended solids, the method comprising:
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a. removing hardness from the produced water by 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 to remove calcium carbonate hardness; iii. in one reactor mixing a caustic with the produced water to remove magnesium hardness 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 suspended solids 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 to at least one reactor; 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 at said pH 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, 7, 8, 9, 10, 11, 12)
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13. A method for treating wastewater containing contaminants including organics, silica, 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 to remove calcium carbonate hardness; iii. in one reactor mixing a caustic with the wastewater to remove magnesium hardness 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 to at least one reactor; f. after ion exchange softening, directing the wastewater though a cartridge filtration unit to further separate contaminants from the wastewater; and g. directing wastewater at said pH 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 (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification