Sodium nitrite oxidation of hydrogen sulfide

1. A method for removing hydrogen sulfide from a solution:

(A) adding sodium nitrite to a solution comprising hydrogen sulfide;

(B) allowing the sodium nitrite to react with the hydrogen sulfide for a period of time; and

(C) blowing an ammonia-removal gas onto the solution to remove free ammonia from the solution.

2. The method of claim 1 wherein the concentration of the hydrogen sulfide in the solution is up to about 25,000 mg/liter.

3. The method of claim 1 , wherein the sodium nitrite is added at a mole ratio to the hydrogen sulfide from about 1:3 to about 2:3.

4. The method of claim 1 , wherein the sodium nitrite is added at a weight ratio to the hydrogen sulfide from about 0.676:1 to about 5:1.

5. The method of claim 1 , wherein step (B) occurs at a temperature between about ambient temperature and about a boiling temperature of the solution.

6. The method of claim 1 , wherein step (B) occurs at a temperature between about 40° C. and about 70° C.

7. The method of claim 1 , wherein step (B) occurs at a temperature of about 45° C.

8. The method of claim 1 , wherein the time period is between about 0 and 24 hours.

9. The method of claim 1 , wherein the solution is disposed in a vessel.

10. The method of claim 1 , wherein the ammonia-removal gas is nitrogen.

11. The method of claim 1 , wherein the ammonia-removal gas is air.

12. The method of claim 1 , wherein step (C) maintains the pH of the solution to about 7.0 to about 9.0.

13. The method of claim 1 , further comprising (D) adding a pH buffer to the solution to reduce pH levels.

14. The method of claim 13 , wherein step (D) occurs once the time period reaches 2 hours.

15. The method of claim 13 , wherein the pH buffer comprises citric acid.

16. The method of claim 13 , wherein the pH buffer comprises phosphoric acid.

17. The method of claim 13 , wherein step (D) further maintains the pH of the solution to about 7.0 to about 9.0.