Integrated electro-pressure membrane deionization system

• US 20060144787A1
• Filed: 01/06/2005
• Published: 07/06/2006
• Est. Priority Date: 01/06/2005
• Status: Active Grant

• Current Assignee: EET Corporation
• Original Assignee: EET Corporation
• Inventors: Williams, Michael E., Sferrazza, Alois F., Schmidt, Ernst
• Granted Patent: US 7,501,064 B2
• Time in Patent Office: Days
• US Class Current: 210/637
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/027 Nanofiltration
• CPC Class Codes: B01D 61/422 Electrodialysis
• CPC Class Codes: B01D 61/423 comprising multiple electrodialysis steps
• CPC Class Codes: B01D 61/44 Ion-selective electrodialysis
• CPC Class Codes: B01D 61/58 Multistep processes
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 1/442 by nanofiltration
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/469 by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
• CPC Class Codes: C02F 1/4693 electrodialysis
• CPC Class Codes: Y10S 204/905 Heavy metal agent

Abstract

An integrated treatment system using electrodialysis and pressure-driven membranes for deionizing and decontaminating liquids to a near-pure quality for use or reuse in industrial or municipal operations. The integrated system includes steps of pre-filtering contaminated feed liquids blending the filtered liquids in preparation for treating the mixed liquids in parallel or sequential treatment steps utilizing nanofiltration or reverse osmosis, proceeded by or followed by an integrated electrodialysis treatment. A control means selectively directs mixed liquids to each of the treatment units for treatment in parallel or in series depending on the conductivity and residual contaminants in the mixed liquids. In comparison with nanofiltration or reverse osmosis only systems, or electrodialysis only systems, the integrated system provides improved efficiencies for treatment, requires less energy to operate, and reduces maintenance and capital costs.

Claims

1. A membrane-based system for treating contaminated feed liquids, comprising the steps of:

providing contaminated feed liquids having a plurality of insoluble and soluble contaminants and ionic constituents therein;

removing insoluble particles from said contaminated feed liquids in a pretreatment filtration unit for removal of particles thereby generating a pretreated filtrate liquid;

channeling said pretreated filtrate liquid to a mixing unit for blending thereby forming a blended filtrate liquid;

filtering insoluble contaminants from said blended filtrate liquid in a microfiltration unit in fluidic connection with said mixing unit;

transferring a selected flow rate of said blended filtrate liquid to an electric-driven membrane unit;

separating ionic constituents in said blended filtrate liquid during passage through said electric-driven membrane unit having a plurality of electrically charged membranes interspaced with gaskets and having channels therebetween, said separating step providing electric-driven membrane removal of ionic constituents thereby forming a deionized product liquid and a separated ionic diluate liquid;

redirecting said separated ionic diluate liquid to said mixing unit for additional blending and further treatment by said step of separating ionic constituents; and

removing said deionized product liquid from said membrane-based system for reuse.

2. The system of claim 1 further comprising the step of:

controlling flow of pretreated filtrate liquid transferring to said electric-driven membrane unit, wherein said step of separating ionic constituents is continuously occurring in parallel with said step of filtering soluble contaminants from said blended filtrate liquid before transfer through said electric-driven membrane unit.

3. The system of claim 2 wherein said step of separating ionic constituents includes:

providing an electrodialysis unit having at least one each of anode and cathode energized membranes; and

securing a plurality of membranes having liquid flow channels therein interspaced with a plurality of spacers and interleaved with said energized membranes to define said electrodialysis unit through which said blended filtrate liquid is transferred therethrough by said step of transferring, whereby said ionic constituents are separated and diverted for removal from said electrodialysis unit by induced transport across said anode and cathode energized membranes thereby said deionized product liquid is separated from said separated ionic diluate liquid and redirected to said mixing unit for additional blending and further treatment by said step of separating.

4. The system of claim 2 further comprising the step of:

pressurizing said deionized product liquid during passage through a pressure-driven membrane unit having a plurality of permeable membranes responsive to pressure-driven flow differences of said deionized product liquid for separation of soluble contaminants from said deionized product liquid thereby generating a decontaminated product liquid.

5. The system of claim 4 wherein said step of pressurizing including pressurizing said deionized product liquid during passage through said pressure-driven membrane unit to pressures between about 50 pounds per square inch to about 400 pounds per square inch maintained on opposed inflow and outflow portions of said pressure-driven membrane unit including a plurality of nanofiltration membranes for removal of soluble contaminants from said deionized product liquid for generating said decontaminated product liquid.

6. The system of claim 4 wherein said step of pressurizing including pressurizing said deionized product liquid during passage through said pressure-driven membrane unit to pressures between about 200 pounds per square inch to about 1,000 pounds per square inch maintained on opposed inflow and outflow portions of said pressure-driven membrane unit including a plurality of reverse osmosis membranes for removal of soluble contaminants from said deionized product liquid for generating said decontaminated product liquid.

7. A membrane-based system for treating contaminated feed liquids, comprising the steps of:

providing contaminated feed liquids having a plurality of insoluble and soluble contaminants, and ionic constituents therein;

filtering said contaminated feed liquids in a pretreatment filtration unit for removal of particles thereby generating a pretreated filtrate liquid;

channeling said pretreated filtrate liquid to a mixing unit for blending thereby forming a blended liquid;

separating ionic constituents from said blended liquid during passage through an electric-driven membrane unit having a plurality of electrically charged membranes interspaced with gaskets and having channels therebetween, said separating step providing electric-driven membrane removal of ionic constituents thereby forming a deionized product liquid and a separated ionic diluate liquid;

returning said deionized product liquid to said mixing tank for blending with said blended liquid;

transferring a selected flow rate of said blended filtrate liquid to a pressurization unit;

discarding said ionic diluate liquid from said electric-driven membrane unit;

pressurizing said deionized product liquid during passage through a pressure-driven membrane unit having a plurality of permeable membranes responsive to pressure-driven flow of said deionized product liquid for separation of soluble contaminants from said deionized product liquid thereby generating a decontaminated product liquid separated from a deionized concentrated liquid; and

removing said decontaminated product liquid from said pressure-driven membrane unit for reuse.

8. The system of claim 7 further comprising the step of:

controlling flow of pretreated filtrate liquid transferring to said electric-driven membrane unit, wherein said step of separating ionic constituents is continuously occurring in parallel with said step of pressurizing said deionized product liquid thereby generating said decontaminated product liquid separated from said deionized concentrated liquid.

9. The system of claim 7 further comprising the step of:

controlling the flow of pretreated blended filtrate liquid transferring to said step of separating ionic constituents whereby said steps of separating and pressurizing are occurring in series thereby generating said decontaminated product liquid separated from said deionized concentrated liquid.

10. The system of claim 7 wherein said step of separating ionic constituents includes:

providing an electrodialysis unit having at least one each of anode and cathode energized membranes; and

securing a plurality of spacers interleaved with said energized membranes to define said electrodialysis unit through which said blended filtrate liquid is transferred by application of continuous liquid flow therethrough whereby said ionic constituents are separated and diverted for removal across said anode and cathode energized membranes thereby said deionized liquids are separated for removal from said electrodialysis unit.

11. The system of claim 7 wherein said step of pressurizing includes:

providing said plurality of membranes for separation of contaminants from said deionized product liquid, said plurality of permeable membranes being configured as an ultrafiltration unit, a nanofiltration unit, or a reverse osmosis unit through which said ionic diluate liquid is pressure driven across a plurality of semi-permeable membranes whereby said semi-permeable membranes selectively separate said ionic diluate liquid into said decontaminated product liquid separate from said deionized concentrated liquid.

12. An apparatus for electrodialysis treatment of contaminated feed liquids, comprising:

a pretreatment filtration unit having at least one filtration membrane through which contaminated feed liquids are directed, said at least one filtration membrane having sufficient pore diameters to deny passage of insoluble particles and to allow passage of filtrate liquids, said pretreatment filtration unit having at least one effluent channel for passage of said filtrate liquids;

a mixing unit in hydraulic connection with said at least one effluent channel of said pretreatment filtration unit, said mixing unit including means for mixing fluids transferred to said mixing unit; and

an electrodialysis unit in hydraulic connection with said mixing unit, said electrodialysis unit including a stacked configuration of a plurality of interdisposed anion cell membranes and cation cell membranes interleaved with a plurality of spacers, said electrodialysis unit providing at least one fluid path therethrough for movement of said filtrate liquids whereby a deionized product liquid and partially deionized fluids are separated from said filtrate liquids by said at least one fluid path through said stacked configuration of said electrodialysis unit with said deionized product liquid channeled for release from said electrodialysis unit; and

a recycle conduit through which partially deionized fluids are transferred to said mixing unit.

13. The apparatus of claim 12 further comprising:

a pressure-driven filtration unit including at least one of a nanofiltration or reverse osmosis membrane through which said deionized product liquid is channeled for separation of ionic and nonionic contaminants from said deionized product liquid, at least one of said nanofiltration or reverse osmosis membrane having a plurality of fluid paths through which said deionized product liquid is pressure driven whereby said pressure-driven filtration unit separates said deionized product liquid into a decontaminated product liquid and a concentrated liquid;

an effluent channel for release of said decontaminated product liquid from said pressure-driven filtration unit; and

at least one recycle channel through which said concentrated liquid is transferred to said mixing unit.

14. The apparatus of claim 13 further comprising:

a computer circuitry controlling flow of filtrate liquids transferred through said mixing tank and said electrodialysis unit, whereby said computer circuitry controls flow to said electrodialysis unit in parallel with movement of said filtrate liquid through at least one of said nanofiltration or reverse osmosis membrane thereby said decontaminated product liquid is separated from said concentrated liquid.

15. The apparatus of claim 13 further comprising:

a computer circuitry controlling flow of filtrate liquids transferred to said mixing tank and said electrodialysis unit, whereby said computer circuitry controls flow to said electrodialysis unit in series with said deionized product liquid channeled through at least one of said nanofiltration or reverse osmosis membrane thereby said decontaminated product liquid is separated from said concentrated liquid.

16. The apparatus of claim 12 wherein said electrodialysis unit further includes:

said stacked configuration having at least one each of anode and cathode energized membranes; and

said plurality of spacers interleaved with said anode and cathode energized membranes to define said stacked configuration through which said pretreated filtrate liquids are transferred by application of continuous liquid flow therethrough whereby said ionic constituents are diverted for removal from said stacked configuration and said deionized product liquid is separated for release from said electrodialysis unit.

17. A method of electrodialysis and pressure driven filtration treatment of contaminated feed liquids comprising the steps of:

pretreating by filtration of contaminated feed liquids having inorganic contaminants and organic contaminants mixed therein, wherein said pretreating step removes particulates and generates pretreated filtrate liquids;

channeling said pretreated filtrate liquids channeled to a mixing unit for blending with additional pretreated filtrate liquids;

directing said mixed pretreated filtrate liquids through a pressure driven membrane unit providing pressure induced liquid transfer across permeable membranes thereby generating a permeate liquid stream and a concentrated reject liquid;

deionizing said permeate liquid stream by pumping through a multiple flow path electrodialysis unit, said step of electrically treating producing a ionic diluate liquid portion channeled to a storage unit, and further producing a decontaminated product liquid portion directed for exiting said electrodialysis unit; and

channeling said ionic diluate liquid portion for mixing in said mixing unit with said pretreated filtrate liquids; and

redirecting said concentrated reject liquid for mixing in said mixing unit with said ionic diluate liquid portion.

18. The method of claim 17 wherein said step of deionizing includes:

providing said multiple flow path electrodialysis unit with a plurality of electrodialysis membranes in a stacked configuration including a cathode electrode plate and an anode electrode plate between which a plurality of spacers are interleaved with said plurality of electrodialysis membranes whereby a plurality of fluid flow paths are maintained within said electrodialysis unit; and

supplying a voltage differential between said cathode electrode plate and said anode electrode plate, whereby said step of deionizing produces said decontaminated product liquid directed for existing said electrodialysis unit.

19. The method of claim 18 wherein said contaminated feed liquids include glycol based thermal transfer liquids.

20. A method for treatment of contaminated ionized liquids, comprising the steps of:

providing contaminated feed liquids having a plurality of insoluble and soluble contaminants, and ionic constituents therein;

channeling said contaminated feed liquids to a mixing unit for blending;

pressurizing said contaminated feed liquids during passage through a pressure-driven filtration unit for filtration of insoluble particle contaminants from the contaminated ionized liquids, said pressuring step produces a filtered permeate liquid;

purifying said filtered permeate liquid utilizing an electrodialysis membrane stack unit having a plurality of electrically charged layers interspaced with nonconducting layers, said purifying step providing removal of ionic constituents thereby forming a decontaminated product liquid and a separated ionic diluate liquid;

redirecting said separated ionic diluate liquid to said mixing unit for additional blending and further treatment of blended ionic diluate liquid by said steps of pressurizing and purifying; and

removing said decontaminated product liquid from said purifying step for reuse in commerce.