Ammonium/ammonia removal from a stream

• US 20070039893A1
• Filed: 08/11/2005
• Published: 02/22/2007
• Est. Priority Date: 08/11/2005
• Status: Active Grant

• Current Assignee: ThermoEnergy Corporation
• Original Assignee: CASTion Corporation (ThermoEnergy Corporation)
• Inventors: Brown, Stephen, Simon, Mark, Kemp, Philip
• Granted Patent: US 7,270,796 B2
• Time in Patent Office: Days
• US Class Current: 210/660
• CPC Class Codes: B01D 2251/506 Sulfuric acid
• CPC Class Codes: B01D 53/58 Ammonia
• CPC Class Codes: C02F 1/20 by degassing, i.e. liberation of dissolved gases degasification of liquids in general B01D19/00; arrangement of degassing apparatus in boiler feed supply F22D
• CPC Class Codes: C02F 1/42 by ion-exchange ion-exchange in general B01J
• CPC Class Codes: C02F 1/66 by neutralisation; pH adjustment for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58
• CPC Class Codes: C02F 2001/425 using cation exchangers
• CPC Class Codes: C02F 2101/16 Nitrogen compounds, e.g. ammonia
• CPC Class Codes: C02F 2301/063 Underpressure, vacuum
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

In one embodiment, an ammonium removal method can comprise: removing a multivalent cation from a stream comprising ammonium to form a treated stream; converting the ammonium in the stream to ammonia by increasing the pH of the stream; and separating the ammonia from the treated stream to form a separated stream and gaseous ammonia. In another embodiment, an ammonium removal method can comprise: a multivalent cation from a stream comprising ammonium to form a treated stream comprising a total of less than or equal to about 50 ppm by weight of multivalent cations; increasing the pH of the stream to a conversion pH; converting the ammonium to ammonia; and separating the ammonia from the treated stream to form a separated stream and gaseous ammonia.

Claims

1. An ammonium removal method, comprising:

removing a multivalent cation from a stream comprising ammonium to form a treated stream;

converting the ammonium in the stream to ammonia by increasing the pH of the stream; and

separating the ammonia from the treated stream to form a separated stream and gaseous ammonia.

2. The method of claim 1, further comprising reducing a pH of the ammonia to a pH of less than or equal to about 5.

3. The method of claim 1, further comprising removing solids from the aqueous stream prior to the removal of the multivalent cations.

4. The method of claim 1, wherein the multivalent cation comprises an ion of a metal selected from the group consisting of Ca, Ba, Sr, Fe, Mg, Mn, a transition metal, and combinations comprising at least one of the foregoing metals.

5. The method of claim 1, wherein the metal is selected from the group consisting of Ca, Mg, and combinations comprising at least one of the foregoing metals.

6. The method of claim 1, wherein removing a multivalent cation further comprises contacting the stream with an ion exchange metal scavenger.

7. The method of claim 1, wherein greater than or equal to about 50 wt % of the ammonium in the stream is converted to the ammonia.

8. The method of claim 7, wherein greater than or equal to about 80 wt % of the ammonium in the stream is converted to the ammonia.

9. The method of claim 8, wherein greater than or equal to about 90 wt % of the ammonium in the stream is converted to the ammonia.

10. The method of claim 1, wherein each of the multivalent cations in the stream are removed to a level of less than or equal to about 50 ppm by weight.

11. The method of claim 10, wherein each of the multivalent cations in the stream are removed to a level of less than or equal to about 25 ppm by weight.

12. The method of claim 11, wherein each of the multivalent cations in the stream are removed to a level of less than or equal to about 3 ppm by weight.

13. The method of claim 1, wherein the conversion occurs without the formation of struvite.

14. The method of claim 1, wherein Mg in the stream is removed to a level of less than or equal to about 1 ppm by weight.

15. The method of claim 1, wherein each of the multivalent cations in the stream are removed to a level adjusting a pH of the treated stream to meet discharge parameters.

16. The method of claim 1, further comprising reacting the gaseous ammonia with sulfuric acid to form ammonium sulfate.

17. The method of claim 1, wherein separating the ammonia from the treated stream further comprises stripping the ammonia from the treated stream in a vacuum assisted flash stripping tower.

18. The method of claim 17, further comprising creating a vacuum with a venturi.

19. An ammonium removal method, comprising:

removing a multivalent cation from a stream comprising ammonium to form a treated stream comprising a total of less than or equal to about 3 ppm by weight of multivalent cations;

increasing the pH of the stream to a conversion pH;

converting the ammonium to ammonia; and

separating the ammonia from the treated stream to form a separated stream and gaseous ammonia.

20. The method of claim 19, wherein the pH is increased without the precipitation of a sparingly soluble salt.

21. An ammonium removal method, comprising:

removing solids from a stream comprising ammonium;

contacting the stream with an ion exchange metal scavenger to remove a multivalent cation from the stream to form a treated stream;

increasing a pH of the treated stream greater than or equal to about 9;

converting the ammonium to ammonia;

stripping the ammonia from the treated stream to form a separated stream and an ammonia stream; and

reducing the pH of the ammonia stream.

22. The method of claim 21, wherein the ion exchange metal scavenger comprises an iminodiacetate functional chelating resin.

23. An ammonium removal system, comprising:

a solids removal tank;

a multivalent cation remover disposed downstream of the solids removal tank and capable of removing a multivalent cation from a stream to form a treated stream;

a base source capable of sufficiently increasing a pH of the treated stream to convert greater than or equal to about 50 wt % of ammonium in the stream to ammonia;

an ammonia removal tank capable of separating the ammonia from the treated stream; and

an ammonia recovery device.

24. The system of claim 23, wherein the ammonia removal tank comprises a flash stripping tower.

25. The system of claim 23, wherein the ammonia recovery device comprises a venturi in fluid communication with a sulfuric acid source.

26. The system of claim 23, wherein the multivalent cation remover comprises an ion exchange metal scavenger, precipitation clarifier, microfilter, water softener, acid cation exchange, air floatation, lime softener, and a combination comprising at least one of the foregoing multivalent cation removers

27. The system of claim 26, wherein the multivalent cation remover comprises an ion exchange metal scavenger.

28. The system of claim 23, wherein the base source is capable of sufficiently increasing a pH of the treated stream to convert greater than or equal to about 80 wt % of ammonium in the stream to ammonia.

29. An ammonium removal system, comprising:

an ion exchange metal scavenger disposed downstream of the solids removal tank and capable of removing a multivalent cation from a stream to form a treated stream;

a base source capable of sufficiently increasing the pH of the treated stream to convert greater than or equal to about 80 wt % of ammonium in the stream to ammonia;

a flash stripping tower capable of receiving the treated stream and separating the ammonia from the treated stream; and

a venturi disposed in fluid communication with the stripping tower and in fluid communication with a sulfuric acid source.

30. The system of claim 29, wherein the ion exchange metal scavenger is a water softener capable of regeneration with sodium chloride.