BIOLOGICAL SCRUBBER ODOR CONTROL SYSTEM AND METHOD

• US 20070180802A1
• Filed: 02/08/2006
• Published: 08/09/2007
• Est. Priority Date: 02/08/2006
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC (Xylem, Inc.)
• Original Assignee: USFilter Corp (Siemens AG)
• Inventors: Parker, Richard, Davis, Eric, Jain, Roop
• Granted Patent: US 7,276,366 B2
• Time in Patent Office: Days
• US Class Current: 55/485
• CPC Class Codes: B01D 2257/30 Sulfur compounds
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/40 Nitrogen compounds
• CPC Class Codes: B01D 2257/406 Ammonia
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y10S 423/05 Automatic, including computer, control
• CPC Class Codes: Y10S 423/17 Microbiological reactions

Abstract

A system and method for the purification and biodeodorizing of a gas are disclosed. The system is highly adaptable and capable of operating in a variety of modes to tailor performance of the system to specific odor control applications. The scrubber stages of the system may each be maintained at different conditions to selectively promote bacterial activity that targets a variety of odorous constituents. The pH level of the irrigation fluid provided to each scrubber stage may be controlled.

Claims

1. An odor treatment system, comprising:

a biological scrubber disposed to receive process gas, the biological scrubber comprising a first scrubber stage, a second scrubber stage and a scrubber sump in fluid communication with the first scrubber stage;

an irrigation source fluidly connected to the biological sc rubber; and

a controller configured to generate a first control signal that establishes a first liquid circuit from the scrubber sump to the biological scrubber and further configured to generate a second control signal that establishes a second liquid circuit from the irrigation source to the biological scrubber.

2. The system of claim 1, wherein the first liquid circuit fluidly connects the scrubber sump to the first scrubber stage.

3. The system of claim 1, wherein the second liquid circuit fluidly connects the irrigation source to the second scrubber stage.

4. The system of claim 1, wherein the first control signal is generated during a predetermined time interval and the second control signal is generated after the predetermined time interval has elapsed.

5. The system of claim 1, further comprising a nutrient reservoir fluidly connected to one or more of the scrubber sump and the irrigation source.

6. The system of claim 5, wherein the controller is further configured to introduce nutrients from the nutrient reservoir into one or more of the first liquid circuit and the second liquid circuit.

7. The system of claim 1, further comprising a polishing system fluidly connected to an outlet of the biological scrubber.

8. The system of claim 1, further comprising a pH sensor disposed to monitor a pH level of a liquid in the scrubber sump.

9. The system of claim 8, wherein the controller is further configured to generate a third control signal that regulates the pH level based on a pH signal from the pH sensor.

10. A computer-readable medium including computer-readable signals stored thereon defining instructions that, as a result of being executed by a computer, instruct the computer to perform a method of regulating operation of a biological scrubber system comprising acts of:

irrigating a first biological scrubber stage of the biological scrubber system during a first irrigation mode of operation; and

irrigating a second biological scrubber stage of the biological scrubber system during a second irrigation mode of operation;

wherein the first irrigation mode is performed during a first predetermined time period and the second irrigation mode is performed during a second predetermined time period.

11. The computer-readable medium of claim 10, wherein the first irrigation mode of operation comprises regulating a fluid flow from a scrubber sump to the first biological scrubber stage and the second irrigation mode of operation comprises regulating a fluid flow from an irrigation source to the second biological scrubber stage.

12. A method for controlling odor in a gas stream, comprising acts of:

contacting the gas stream with a first biologically active surface;

wetting the first biologically active surface with a first liquid stream;

contacting the gas stream with a second biologically active surface; and

wetting the second biologically active surface with a second liquid stream during a predetermined time interval; and

wetting at least a portion of the first biologically active surface with a discharge from the second biologically active surface.

13. The method of claim 12, further comprising an act of controlling a flow of the first liquid stream and a flow of the second liquid stream.

14. The method of claim 13, wherein the act of controlling a flow of the first liquid stream comprises generating a first control signal that regulates the wetting of the first biologically active surface.

15. The method of claim 14, wherein the act of controlling a flow of the second liquid stream comprises generating a second control signal that regulates the wetting of the second biologically active surface.

16. The method of claim 15, further comprising an act of withdrawing liquid from a liquid reservoir to form at least part of the second liquid stream.

17. The method of claim 16, further comprising an act of collecting a mixture of the first and second liquid streams.

18. The method of claim 17, further comprising an act of delivering the mixture to the first biologically active surface.

19. The method of claim 18, further comprising an act of monitoring a pH level of the mixture.

20. The method of claim 19, further comprising an act of adjusting the pH level of the mixture to maintain a predetermined pH level of the mixture.

21. The method of claim 20, further comprising an act of reducing a concentration of any residual target constituent in the gas stream with a polishing system.

22. The method of claim 12, further comprising an act of supplying nutrients to one or more of the first and second liquid streams.

23. The method of claim 12, wherein the act of wetting the first biologically active surface is performed while performing the act of wetting the second biologically active surface.

24. A method for treating odor in a fluid, comprising acts of:

contacting the fluid with a first active surface;

wetting the first active surface with a first liquid stream having an acidic pH;

contacting the fluid with a second active surface; and

wetting the second active surface with a second liquid stream having a pH greater than the pH of the first liquid stream.

25. The method of claim 24, wherein the first and second active surfaces are biologically active.

26. The method of claim 25, wherein the pH of the first liquid stream is about 2 pH units.

27. The method of claim 26, wherein the act of wetting the first active surface is performed during a predetermined time interval.

28. The method of claim 27, wherein the act of wetting the second active surface is performed after the predetermined time interval expires.

29. A method for controlling odor in a gas stream, comprising acts of:

providing a scrubber column;

establishing a first liquid circuit for a predetermined period of time from a scrubber sump to a first biologically active stage of the scrubber column;

establishing a second liquid circuit from an irrigation source to a second biologically active stage of the scrubber column after the predetermined period of time has elapsed; and

contacting the gas stream with the first and second biologically active surfaces to reduce a concentration of odorous constituents therein.

30. The method of claim 29, further comprising an act of delivering a predetermined amount of liquid from the irrigation source to the second biologically active stage before the act of establishing the first liquid circuit.

31. The method of claim 29, further comprising acts of terminating the second liquid circuit and reestablishing the first liquid circuit.

32. The method of claim 29, further comprising an act of maintaining a pH level of the first liquid circuit within a predetermined pH range.

33. A method for treating odor in a gas stream, comprising acts of:

providing a scrubber column comprising a scrubber sump, a first biologically active stage and a second biologically active stage;

contacting the gas stream with the first and second biologically active stages to reduce a concentration of target constituents;

directing liquid from the scrubber sump to the first biologically active stage;

maintaining a pH level of the liquid from the scrubber sump within a predetermined pH range; and

directing liquid from an irrigation source to the second biologically active stage.

34. The method of claim 33, wherein the act of maintaining a pH level of the liquid from the scrubber sump involves draining liquid from the scrubber sump.

35. The method of claim 34, wherein the act of directing liquid from the scrubber sump to the first biologically active stage is performed for a predetermined period of time.

36. The method of claim 35, wherein the act of directing liquid from an irrigation source to the second biologically active stage is performed when the predetermined period of time expires.

37. The method of claim 33, further comprising an act of supplying nutrients to one or more of the first and second biologically active stages.

38. A method of facilitating controlling odor in a gas stream, comprising:

providing a biological scrubber column comprising an inlet fluidly connected to a source of the gas stream; and

providing a controller configured to generate a first control signal that establishes a first liquid circuit from a scrubber sump to the biological scrubber column and further configured to generate a second control signal that establishes a second liquid circuit from an irrigation source to the biological scrubber column.

39. A method of modifying an existing biological odor control system, comprising:

providing a computer-readable medium including computer-readable signals stored thereon defining instructions that, as a result of being executed by a computer, instruct the computer to perform a method of regulating operation of a biological scrubber system comprising acts of;

irrigating a first biological scrubber stage of the biological scrubber system during a first irrigation mode of operation; and

irrigating a second biological scrubber stage of the biological scrubber system during a second irrigation mode of operation;

wherein the first irrigation mode is performed during a first predetermined time period and the second irrigation mode is performed during a second predetermined time period.