Mixing chamber

• US 8,372,282 B2
• Filed: 12/05/2003
• Issued: 02/12/2013
• Est. Priority Date: 12/05/2002
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Zha, Fufang, Phelps, Roger William, Brois, Etienne Ulysse
• Primary Examiner(s): Menon, Krishnan S
• Application Number:
  US10/537,760
• Publication Number:
  US 20070007214A1
• Time in Patent Office: 3,357 Days
• Field of Search: None
• US Class Current: 210/321.69
• CPC Class Codes: B01D 2313/105 Supply manifolds
• CPC Class Codes: B01D 2313/32 Intermediate chambers
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 2321/04 Backflushing
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 63/02 Hollow fibre modules
• CPC Class Codes: B01D 63/024 with a single potted end
• CPC Class Codes: B01D 63/04 comprising multiple hollow fibre assemblies
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration
• CPC Class Codes: B01D 65/08 Prevention of membrane fouling or of concentration polarisation

Abstract

A membrane module (5) including a plurality of porous membranes (6) extending in an array and mounted, at least at one end, in a header (8). The header (8) has a number of distribution apertures (11) for distributing a fluid into the module (5) and along a surface or surfaces of the membranes (6). An elongate chamber (10) having one open end (13) and another end is in fluid communication with the distribution apertures (11) for distributing the fluid to the distribution apertures (11).

Claims

1. A membrane filtration apparatus comprising:

a plurality of membrane filtration modules, each membrane filtration module comprising;

a plurality of porous membranes extending in an array, said plurality of porous membranes encased in a support structure and having lower ends mounted in a lower pot supported by a lower header and upper ends mounted in an upper pot supported by an upper header, said upper header configured to provide for permeate to be withdrawn from said upper ends of said plurality of porous membranes; and

a plurality of distribution apertures defined in said lower pot, said distribution apertures configured to distribute a scrubbing fluid into said module and along a surface or surfaces of said membranes;

a single manifold coupled to said lower header of each of said plurality of membrane filtration modules; and

a single chamber positioned below, and connected to, said manifold, said chamber constructed and arranged to promote upward flow of feed liquid therethrough, said chamber comprising;

an open base end in fluid communication with a source of feed liquid;

a second end in fluid communication with said distribution apertures; and

a single gas inlet constructed and arranged to introduce gas into said chamber in a downward direction from above the open base end, said gas fed from above and through said manifold and into said chamber, said gas inlet centered between at least two of said plurality of membrane filtration modules and configured to release gas into said chamber at a position vertically displaced below said at least two of said plurality of membrane filtration modules,

said chamber configured to mix gas and liquid to produce said scrubbing fluid and further configured to distribute said scrubbing fluid to said distribution apertures.

2. The membrane filtration apparatus according to claim 1 wherein the chamber is elongate.

3. The membrane filtration apparatus according to claim 1 wherein the length of said chamber is greater than that required to provide a static head, when the membrane is immersed in a liquid and gas introduced into the chamber, equivalent to the head loss for the gas to flow to said distribution apertures.

4. The membrane filtration apparatus according to claim 1 wherein the chamber is enclosed on all sides.

5. The membrane filtration apparatus according to claim 1 wherein the chamber comprises a plurality of sides positioned to form a skirt directly beneath a header or plurality of headers.

6. The membrane filtration apparatus according to claim 1 wherein said plurality of membrane filtration modules are arranged in the form of an extended linear array, and wherein the chamber has enclosed long sides.

7. The membrane filtration apparatus according to claim 6 wherein the chamber has unenclosed short sides.

30. The membrane filtration apparatus of claim 1 wherein said gas inlet is fluidly connected to a source of gas within said chamber.

31. The membrane filtration apparatus of claim 30 wherein said source of gas is coupled to a gas line which runs through said header.

8. An assembly of membrane modules comprising:

a plurality of porous membranes extending in an array and having lower ends mounted in a plurality of lower pots supported by a plurality of respective lower headers, and upper ends mounted in a plurality of upper pots supported by a plurality of respective upper headers, said lower pots being configured to provide a number of distribution apertures therein for distributing a scrubbing fluid into said assembly of membrane modules and along a surface or surfaces of said membranes, said lower headers coupled to a manifold; and

a chamber positioned below and connected to said manifold, said chamber constructed and arranged to promote upward flow of feed liquid therethrough, said chamber comprising;

an open base end in fluid communication with a source of feed liquid;

a second end in fluid communication with said distribution apertures; and

a gas inlet constructed and arranged to introduce gas into said chamber in a downward direction from above the open base end, said gas fed from above and through said manifold,

said chamber configured to mix gas and liquid to produce said scrubbing fluid and further configured to distribute said scrubbing fluid to said distribution apertures.

9. The assembly of membrane modules according to claim 8 wherein the chamber is elongate.

10. The assembly of membrane modules according to claim 8 wherein the length of said chamber is greater than that required to provide a static head, when the membrane is immersed in a liquid and gas introduced into the chamber, equivalent to the head loss for the gas to flow to said distribution apertures.

11. The assembly of membrane modules according to claim 8 wherein the chamber is enclosed on all sides.

12. The assembly of membrane modules according to claim 8 wherein the chamber comprises a plurality of sides positioned to form a skirt directly beneath a header or plurality of headers.

13. The assembly of membrane modules according to claim 8 when arranged in the form of an extended linear array wherein the chamber has enclosed long sides.

14. The assembly of membrane modules according to claim 8 in the form of an extended linear array wherein the chamber has unenclosed short sides.

32. The assembly of membrane modules of claim 8 wherein said gas inlet runs through said header.

15. A membrane filtration apparatus comprising:

a plurality of membrane filtration modules, each membrane filtration module comprising a plurality of porous membranes, said membranes being arranged in close proximity to one another and having lower ends mounted in a lower pot supported by a lower header and upper ends mounted in an upper pot supported by an upper header, said upper header configured to provide for permeate to be withdrawn from said upper ends of said porous membranes;

a manifold coupled to said lower headers;

an open-ended mixing chamber constructed and arranged to provide a cleaning mixture by mixing together liquid and gas bubbles, said chamber immersed in a feed tank and having an open base in fluid communication with a source of feed liquid, said chamber constructed and arranged to promote upward flow of feed liquid therethrough;

a gas source positioned within the open-ended mixing chamber, the gas source constructed and arranged to introduce gas through a single gas inlet into the open-ended mixing chamber in a downward direction from above the open base, said gas fed from above and through said manifold and into said chamber, said single gas inlet centered within said plurality of membrane modules; and

means for flowing said cleaning mixture along a surface of said membranes to dislodge fouling materials therefrom.

16. A membrane bioreactor comprising:

a plurality of membrane filtration modules, each membrane filtration module comprising a plurality of porous hollow membrane fibres extending longitudinally between and mounted between an upper and a lower potting head, said membrane fibres being arranged in close proximity to one another, said fibres being partitioned into a number of bundles at least at or adjacent to their respective potting head so as to form a space therebetween;

a header in which the lower potting head is supported;

a manifold coupled to the header;

an open-ended mixing chamber positioned below the lower potting head, said chamber constructed and arranged to promote upward flow of feed liquid therethrough, said chamber having an open base in fluid communication with a source of feed liquid; and

a gas inlet positioned within the open-ended mixing chamber, the gas inlet spaced from and surrounded by side walls of the open-ended mixing chamber and configured to feed gas into the open-ended mixing chamber from above and through said manifold,

wherein at least one of said potting heads includes an array of openings formed therein in fluid communication with said chamber constructed and arranged to provide gas bubbles within said module such that, in use, said bubbles move past the surfaces of said membrane fibres to dislodge fouling materials therefrom.

17. An assembly of membrane modules for use in a membrane bioreactor comprising:

a plurality of porous hollow membrane fibres extending longitudinally between and mounted between an upper and a lower potting head, said membrane fibres being arranged in close proximity to one another, said fibres being partitioned into a number of bundles at least at or adjacent to their respective potting head so as to form a space therebetween;

a header in which the lower potting head is supported;

a manifold coupled to the header;

an open-ended mixing chamber positioned below the lower potting head, said chamber constructed and arranged to promote upward flow of feed liquid therethrough, said chamber having an open base in fluid communication with a source of feed liquid; and

a gas inlet positioned within the open-ended mixing chamber, the gas inlet spaced from and surrounded by side walls of the open-ended mixing chamber, and centrally located within the open-ended mixing chamber and configured to feed gas into the open-ended mixing chamber from above and through said manifold;

wherein said potting heads are configured to provide a number of distribution apertures therebetween in fluid communication with said chamber for providing gas bubbles within said assembly of membrane modules such that, in use, said bubbles move past the surfaces of said membrane fibres to dislodge fouling materials therefrom.

18. The assembly of membrane modules according to claim 17 wherein the liquid used is feed to the membrane module.

19. The assembly of membrane modules according to claim 17 wherein the fibres within the module have a packing density of between about 5 to about 70%.

20. The assembly of membrane modules according to claim 19 wherein the packing density is between about 8 to about 55%.

21. The assembly of membrane modules according to claim 17 wherein said holes have a diameter in the range of about 1 to 40 mm.

22. The assembly of membrane modules according to claim 21 wherein said holes have a diameter in the range of about 1.5 to about 25 mm.

23. The assembly of membrane modules according to claim 17 comprising a deflector within said mixing chamber configured to deflect gas away from the source of the liquid.

24. The assembly of membrane modules according to claim 17 including a nozzle whereby liquid is introduced into the mixing chamber.

25. A membrane bioreactor comprising a tank having means for the introduction of feed thereto, means for forming activated sludge within said tank, a membrane module or an assembly according to claim 17 positioned within said tank so as to be immersed in said sludge and said membrane module provided with means for withdrawing filtrate from at least one end of said fibre membranes.

26. A method of operating a membrane bioreactor of the type according to claim 25, comprising introducing feed to said tank, applying a vacuum to said fibres to withdraw filtrate therefrom while periodically or continuously supplying a cleaning mixture of gas bubbles and liquid formed in a mixing chamber through said openings to within said module such that, in use, said cleaning mixtures flows along the surface of said membrane fibres to dislodge fouling materials therefrom.

27. A membrane bioreactor according to claim 25 wherein a further source of aeration is provided within the tank to assist microorganism activity.

28. A membrane bioreactor according to claim 27 wherein the membrane module is suspended vertically within the tank and said further source of aeration is provided beneath the suspended module.

29. A membrane bioreactor according to claim 28 wherein the further source of aeration comprises a group of air permeable tube.