MEMBRANE CLEANING WITH PULSED AIRLIFT PUMP

• US 20130153496A1
• Filed: 02/12/2013
• Published: 06/20/2013
• Est. Priority Date: 05/29/2007
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Zha, Fufang, James, Gerin, Zuback, Joseph Edward, Zauner, Peter, Phelps, Roger William
• Granted Patent: US 8,840,783 B2
• Time in Patent Office: Days
• US Class Current: 210/636
• 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 water treatment system comprising:

a membrane module immersed in a liquid feed in a tank;

a flow generating device positioned below the membrane module and having a first inlet fluidly connected to the liquid feed and an outlet fluidly connected to the membrane module; and

a source of gas fluidly connected to a second inlet of the flow generating device, the flow generating device constructed and arranged to provide a two-phase gas/liquid flow that is random in at least one of magnitude, frequency, and duration to the membrane module.

2. The water treatment system of claim 1, wherein the outlet of the flow generating device comprises a tube.

3. The water treatment system of claim 2, wherein the flow generating device comprises a trough constructed and arranged to contain at least one of liquid feed and gas and at least partially surrounds the tube.

4. The water treatment system of claim 2, wherein the tube comprises an inlet fluidly connected to the source of gas.

5. The water treatment system of claim 1, further comprising a control device configured to deliver gas from the source of gas to the flow generating device based on a level of the liquid feed in the tank.

6. The water treatment system of claim 1, further comprising a fluid distributor connected between the flow generating device and the membrane module.

7. The water treatment system of claim 1, wherein the two-phase gas/liquid flow is pulsed.

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

introducing a liquid feed into the tank;

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 liquid feed within the chamber and to distribute a gas/liquid flow at randomly spaced intervals into the membrane module.

9. The method of claim 8, 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.

10. The method of claim 8, 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.

11. The method of claim 10, wherein the first level is at a position below an inlet of the tube.

12. The method of claim 11, further comprising introducing liquid feed into the tube when the level of gas within the chamber reaches a second level.

13. The method of claim 12, wherein the second level is at a position above the inlet of the tube.

14. A method of cleaning a membrane surface immersed in a liquid medium comprising:

providing a fluid flow in the liquid medium; and

pulsing the fluid flow to provide a pulsed fluid flow which is random in at least one of magnitude, frequency and duration.

15. The method according to claim 14, wherein the fluid flow comprises a gas flow.

16. The method according to claim 15, wherein the gas flow comprises gas bubbles.

17. The method according to claim 14, wherein the fluid flow comprises a two phase gas/liquid flow.

18. The method according to claim 14, further comprising providing an additional source of gas to the liquid medium.

19. A method of removing fouling materials from a surface of a plurality of porous hollow fiber membranes mounted and extending longitudinally in an array to form a membrane module, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween, the method comprising:

providing a constant supply of gas from a source of gas;

introducing a pulsed two phase gas/liquid flow that is random in at least one of magnitude, frequency, and duration past the surface of the membranes from the constant supply of gas.

20. The method of claim 19, wherein introducing the pulsed two phase gas/liquid flow comprises pulsing the gas/liquid flow at randomly spaced intervals in a range of about 0.1 seconds to 200 seconds.