Moving aerator for immersed membranes

• US 6,708,957 B2
• Filed: 03/25/2002
• Issued: 03/23/2004
• Est. Priority Date: 10/09/1998
• Status: Expired due to Fees

• Current Assignee: Zenon Technology Partnership
• Original Assignee: Zenon Environmental Incorporated (Veolia Environnement SA)
• Inventors: Guibert, Denis, Cote, Pierre, Pedersen, Steven
• Primary Examiner(s): Bushey, Scott
• Application Number:
  US10/105,843
• Publication Number:
  US 20020139748A1
• Time in Patent Office: 729 Days
• Field of Search: 261/23.1, 261/28, 261/122.1, 261/122.2, 261/124, 261/81, 261/87, 261/93, 210/636, 210/641, 210/644, 210/649, 210/650, 210/651, 210/652, 210/138, 210/142, 210/321.67, 210/321.75, 210/321.78, 210/321.79, 210/321.84, 210/321.88
• US Class Current: 261/23.1
• CPC Class Codes: B01D 2313/18 Specific valves
• 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 2321/04 Backflushing
• CPC Class Codes: B01D 2321/18 Use of gases
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 63/026 Wafer type modules or flat-surface type modules
• CPC Class Codes: B01D 63/031 Two or more types of hollow fibres within one bundle or within one potting or tube-sheet
• CPC Class Codes: B01D 63/043 with separate tube sheets
• 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: B01F 23/23105 Arrangement or manipulation of the gas bubbling devices
• CPC Class Codes: B01F 23/231242 in the form of slits or cut-out openings
• CPC Class Codes: B01F 23/231265 being tubes, tubular elements, cylindrical elements or set of tubes
• CPC Class Codes: B01F 23/2319 Methods of introducing gases into liquid media
• CPC Class Codes: B01F 33/4062 with means for modifying the gas pressure or for supplying gas at different pressures or in different volumes at different parts of the bottom
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/74 with air aeration of stretches of water C02F7/00
• CPC Class Codes: C02F 2209/40 Liquid flow rate
• CPC Class Codes: C02F 2209/44 : Time
• CPC Class Codes: C02F 3/1273 : Submerged membrane bioreactors
• CPC Class Codes: C02F 3/201 : Perforated, resilient plastic diffusers, e.g. membranes, sheets, foils, tubes, hoses
• CPC Class Codes: Y02W 10/10 : Biological treatment of water, waste water, or sewage

Abstract

One or more aerators move below an area of an assembly of immersed filtering membranes to be aerated. The movement can take various forms including the sweep of a pendulum. Positions in the assembly of membranes may be alternately aerated for a period of time and then not aerated for a period of time.

Claims

1. An apparatus for aerating an assembly of immersed filtering membranes, comprising:

one or more aerators for discharging bubbles wherein the one or more aerators move below a portion of the assembly of membranes to be aerated.

2. The apparatus of claim 1 wherein the one or more aerators are suspended from a pivot point above the one or more aerators and move through an arc of a pendulum.

3. The apparatus of claim 1 wherein the one or more aerators move in a generally horizontal back and forth motion.

4. The apparatus of claim 1 wherein the one or more aerators rotate in a generally horizontal plane about a generally vertical axis.

5. The apparatus of claim 1 wherein the one or more aerators have about 50 or less holes for discharging scouring bubbles per square meter of the horizontal area of the portion of the membrane assembly to be aerated.

6. The apparatus of claim 1 wherein the one or more aerators have about 25 or less holes for discharging scouring bubbles per square meter of the horizontal area of the portion of the membrane assembly to be aerated.

7. The apparatus of claim 2 wherein the one or more aerators may be rotated about their pivot point to a position above the membrane assembly to facilitate operations ancillary to aeration.

8. A process for aerating a portion of an assembly of immersed filtering membranes with scouring bubbles, comprising the steps of:

(a) providing one or more aerators for discharging bubbles wherein the one or more aerators may be moved below a portion of the assembly of membranes to be aerated;

(b) supplying a substantially continuous flow of gas through the one or more aerators to produce bubbles from the aerators; and

,

(c) moving the one or more aerators below the portion of the assembly of membranes to be aerated.

9. The process of claim 8 wherein the aerators produce scouring bubbles from holes and the air flow through each aerator hole is sufficient to substantially prevent tank water from creeping into the aerator.

10. The process of claim 8 wherein the one or more aerators are moved below a portion of the assembly of membranes to be aerated such that substantially every position within the horizontal area aerated by the one or more aerators is aerated.

11. The process of claim 8 wherein substantially every position within the horizontal area aerated by the one or more aerators is alternately aerated for a period of time and then not aerated for a period of time.

12. The process of claim 11 wherein the minimum aerated period of time for each position is about 0.5 seconds or more.

13. The process of claim 11 wherein the maximum non-aerated period of time for each position is about 60 seconds or less.

14. The process of claim 11 wherein the maximum non-aerated period of time for each position is between about 15 to 30 seconds.

15. The process of claim 11 wherein the minimum aerated period of time for each position is about 0.5 seconds or more and the maximum non-aerated period of time for each position is between about 15 to 30 seconds.

16. An apparatus for aerating an assembly of immersed filtering membranes, comprising:

an aerator for discharging bubbles wherein the aerator moves below a portion of the assembly of membranes to be aerated through an arc of a pendulum

wherein the horizontal length of the arc of the pendulum is 2 meters or less.

17. The apparatus of claim 16 wherein the horizontal length of the arc of the pendulum is 1 meter or less.

18. A process for aerating a portion of an assembly of immersed filtering membranes with scouring bubbles, comprising the steps of:

(a) providing an apparatus as in claim 16;

(b) supplying a substantially continuous flow of gas through the aerator to produce bubbles from the aerator; and

(c) moving the aerator below an area of the assembly of membranes to be aerated in a repeated movement, the movement having a duration of between about 10 seconds and about 60 seconds.

19. A process for aerating a portion of an assembly of immersed filtering membranes with scouring bubbles, comprising the steps of:

(a) providing an apparatus as in claim 17;

(b) supplying a substantially continuous flow of gas through the aerator to produce bubbles from the aerator; and

(c) moving the aerator below an area of the assembly of membranes to be aerated in a repeated movement, the movement having a duration of between about 10 seconds and about 30 seconds.