Ammonium/ammonia removal from a stream

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 treated stream to ammonia by increasing the pH of the stream; and

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

2. The method of claim 1 , further comprising reducing a pH of the ammonia stream 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 4 , wherein the metal comprises Ca.

6. The method of claim 4 , wherein the metal comprises Mg.

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

8. 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.

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

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

11. 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.

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 25 ppm by weight.

13. The method of claim 12 , 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.

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

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

16. The method of claim 1 , wherein the multivalent cations are removed to a level of less than or equal to about 3 ppm by weight, and further comprising adjusting a pH of the treated stream to meet discharge parameters.

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

18. An ammonium removal method, comprising:

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

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

stripping the ammonia from the treated stream in a vacuum assisted flash stripping tower to form a separated stream and an ammonia stream.

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

20. 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 pH at which ammonium converts to ammonia;

converting the ammonium to ammonia; and

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

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

22. 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 to 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.

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

24. An ammonium removal system, comprising:

removing a multivalent cation from a stream comprising ammonium to form a treated stream, wherein the multivalent cation comprises an ion of Mg;

increasing a pH of the treated stream to greater than or equal to about 9, wherein the ammonium in the stream converts to ammonia; and

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

25. The method of claim 24 , wherein the multivalent cation is removed to a level of less than or equal to about 50 ppm by weight.

26. The method of claim 25 , wherein the multivalent cation is removed to a level of less than or equal to about 1 ppm by weight.

27. The method of claim 24 , wherein greater than or equal to about 80 wt % of the ammonium in the stream is converted to the ammonia.

28. An ammonium removal system, comprising:

removing multivalent cations from a stream comprising ammonium to form a treated stream, wherein each multivalent cation in the stream is removed to a level of less than or equal to about 25 ppm by weight, and wherein the multivalent cations comprises an ion of Mg;

increasing a pH of the treated stream to greater than or equal to about 9, wherein the ammonium in the stream converts to ammonia;

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

reducing a pH of the ammonia stream to less than or equal to about 5.