Water treatment plant with immersed membranes

• US 20050126963A1
• Filed: 10/28/2004
• Published: 06/16/2005
• Est. Priority Date: 10/29/2003
• Status: Active Grant

• Current Assignee: Zenon Technology Partnership
• Original Assignee: Zenon Technology Partnership
• Inventors: Penny, Jeffrey Peter, Diamond, Jason A., Goldstein, Jake, Phagoo, Deonarine, Thompson, Douglas Joseph
• Granted Patent: US 7,879,229 B2
• Time in Patent Office: Days
• US Class Current: 210/110
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 2321/04 Backflushing
• CPC Class Codes: B01D 2321/16 Use of chemical agents
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 61/146 comprising multiple ultrafiltration steps
• CPC Class Codes: B01D 61/20 Accessories; Auxiliary operations
• 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: C02F 1/444 by ultrafiltration or microfiltration

Abstract

A liquid treatment plant has sets of membrane trains and processing trains with flow between them through channels. Means of withdrawing permeate and sludge from the trains are described. Cyclic aeration is provided to the membrane trains. Methods of foam control, backwashing and chemical cleaning are described. Single membrane trains or process trains may be isolated for various functions. An isolated membrane train may be used to thicken sludge.

Claims

1. A liquid treatment plant having,

(a) two or more membrane tanks, each membrane tank having an inlet and an outlet;

(b) a train of cassettes of membrane modules located in each membrane tank;

(c) a membrane tank inlet channel in communication with the inlet of each tank; and

,

(d) a membrane tank outlet channel in communication with the outlet of each membrane tank.

2. The plant of claim 1 wherein a selected membrane tank may be isolated from the membrane tank inlet channel and membrane tank outlet channel.

3. The plant of claim 1 further comprising,

(e) a plurality of processing tanks, each processing tank having an inlet and an outlet;

and,

(f) a processing tank inlet channel in communication with the inlets of the processing tanks, wherein the outlets of the processing tanks are in communication with the membrane tank inlet channel.

4. The plant of claim 3 further comprising a processing tank outlet channel in communication with the outlets of the processing tank and the membrane tank inlet channel.

5. The plant of claim 4 wherein the liquid surface level in the membrane tank inlet channel is lower than the liquid surface level in the processing tank outlet channel.

6. The plant of claim 4 wherein the liquid surface level in the membrane tank inlet channel is higher than the liquid surface level in the processing tank outlet channel.

7. The plant of claim 1 wherein the outlets of the membrane tanks comprise weirs or controlled weirs, gates or valves adapted to maintain a generally common liquid level in the membrane tanks.

8. The plant of claim 7 wherein the outlets of the membrane tanks comprise weirs.

9. The plant of claim 7 wherein aerators in each membrane tank are connected to a common air supply manifold.

10. The plant of claim 7 wherein the train in each tank is connected to a common permeate header.

11. The plant of claim 1 having a foam sump, the foam sump in communication with the liquid through an opening in the foam sump near the surface level of the liquid.

12. The plant of claim 11 wherein the opening has a variable elevation.

13. The plant of claim 11 wherein the foam sump is in communication with liquid in a channel.

14. The plant of claim 11 further comprising foam passages between a volume of water in direct communication with the foam sump and at least one further upstream volume of water.

15. The plant of claim 14 further comprising means to periodically increase the elevation of the liquid surface of the upstream volume to cause a flow of foam over the foam passage.

16. The plant of claim 1 wherein each train has a train permeate header and the train headers are attached to a common plant permeate pipe this is in turn connected to a plurality of parallel permeate pumps, wherein each train header has an isolation valve and each permeate pump may be separately turned on or off.

17. The plant of claim 1 wherein each train has a train permeate header, the train permeate headers are attached to common plant permeate pipe and the plant permeate pipe is connected to a container adapted to maintain a supply of permeate in the common plant permeate pipe, and a reversible pump in line with each train permeate header, the reversible pump adapted to selectively withdraw permeate from the train or backwash the train.

18. The plant of claim 1 wherein aerators associated with each membrane tank are grouped into two or more groups, each group connected to a common air supply manifold, each air supply manifold having an air valve and being connected to a common pipe leading to a supply of air.

19. The plant of claim 18 having a valve controller adapted to cyclically open and close each valve.

20. The plant of claim 19 wherein each air valve is connected to a separate actuator.

21. The plant of claim 1 wherein a second outlet of each membrane tank is in communication with a common tank drain pipe or channel.

22. The plant of claim 21 wherein an outlet of the common tank drain pipe channel may be placed in communication with a fill line to one or more of the membrane tanks.

23. The plant of claim 21 having means of fluid communication and control configurable to allow temporary operation of a membrane train for sludge thickening while another membrane train operates in normal production.