Membrane cleaning with pulsed airlift pump

• US 9,206,057 B2
• Filed: 02/11/2014
• Issued: 12/08/2015
• Est. Priority Date: 05/29/2007
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Inventors: Zha, Fufang, James, Gerin, Zuback, Joseph Edward, Zauner, Peter, Phelps, Roger William
• Primary Examiner(s): BARRY, CHESTER T
• Application Number:
  US14/177,749
• Publication Number:
  US 20140158618A1
• Time in Patent Office: 665 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B01D 2313/21 Specific headers, end caps
• CPC Class Codes: B01D 2313/26 Specific gas distributors or gas intakes
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 2321/2066 Pulsated flow
• 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
• CPC Class Codes: B01D 65/109 Testing of membrane fouling or clogging, e.g. amount or affinity
• CPC Class Codes: C02F 1/001 Processes for the treatment of water whereby the filtration technique is of importance C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00
• CPC Class Codes: C02F 3/1273 Submerged membrane bioreactors
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage

Abstract

A method of cleaning a membrane surface immersed in a liquid medium with a fluid flow, including the steps of providing a randomly generated intermittent or pulsed fluid flow along the membrane surface to dislodge fouling materials therefrom. A membrane module is also disclosed comprising a plurality of porous membranes (6) or a set of membrane modules (5) and a device (11) for providing a generally randomly generated, pulsed fluid flow such that, in use, said fluid flow moves past the surfaces of said membranes (6) to dislodge fouling materials therefrom.

Claims

1. A method of operating a water treatment system positioned in a tank, the system comprising a membrane module including a plurality of hollow fiber membranes, a chamber positioned below the membrane module and having a liquid feed inlet and a gas inlet, the method comprising:

introducing a liquid feed into the chamber;

applying a vacuum to the plurality of hollow fiber membranes; and

introducing a gas to the gas inlet of the chamber at a constant flow rate to displace the liquid feed within the chamber and to distribute a gas/liquid flow at randomly spaced intervals into the membrane module.

2. The method of claim 1, wherein the gas/liquid flow is distributed into the membrane module through an outlet of the chamber fluidly connected to the membrane module.

3. The method of claim 1, wherein the gas/liquid flow is distributed into the membrane module through an outlet of the chamber, the outlet of the chamber comprising a tube.

4. The method of claim 3, wherein the gas is introduced into a trough formed in the chamber and at least partially surrounding the tube.

5. The method of claim 3, wherein the gas in introduced into the outlet of the chamber through an inlet in the tube.

6. The method of claim 1, wherein the gas/liquid flow is random in at least one of magnitude and duration.

7. The method of claim 1, wherein gas is delivered from the source of gas to the chamber based on a level of the liquid feed in the tank.

8. The method of claim 1, further comprising passing the gas/liquid flow though a flow distributor connected between the chamber and the membrane module.

9. The method of claim 1, wherein the gas/liquid flow is pulsed.

10. The method of claim 1, wherein the gas/liquid flow is distributed at randomly spaced intervals in a range of about 0.1 seconds to 200 seconds from the chamber to the membrane module.

11. The method of claim 1, wherein introducing the gas to the gas inlet of the chamber comprises introducing gas into a tube when a level of gas within the chamber reaches a first level.

12. The method of claim 11, wherein the first level is at a position below an inlet of the tube.

13. The method of claim 12, further comprising introducing liquid feed into the tube when the level of gas within the chamber reaches a second level.

14. The method of claim 13, wherein the second level is at a position above the inlet of the tube.

15. The method of claim 1, wherein the gas/liquid flow comprises gas bubbles.

16. The method of claim 1, further comprising flowing the gas/liquid flow past surfaces of the membranes.

17. The method of claim 1, further comprising providing an additional source of gas to the liquid feed.

18. The method of claim 17, wherein the additional source of gas is provided beneath the membrane module.

19. The method of claim 1, wherein the gas is introduced into an inverted gas storage chamber having a closed upper end and an open lower end.

20. The method of claim 19, wherein the gas is introduced into the upper end of the inverted gas storage chamber.