Treatment of hydrogen sulfide gas under aerobic conditions

1. A method for treating an aerobic contaminated gas stream, comprising:

performing a first plurality of activities in a common vessel, the first plurality of activities comprising:

contacting the aerobic contaminated gas stream with a clean aqueous solution comprising approximately 0.5% Ferric MGDA to approximately 100% Ferric MGDA, the aerobic contaminated gas stream comprising air and comprising hydrogen sulfide at a concentration in the air of approximately 5 ppm or higher;

forming bonds between sulfide formed from the hydrogen sulfide and the iron in the Ferric MGDA to create:

an aerobic clean gas stream having a hydrogen sulfide concentration of 3.5 ppm or less; and

a dirty aqueous solution comprising sulfide saturated ferro MGDA;

mixing the dirty aqueous solution with an oxidant; and

via a reaction with the oxidant, breaking the bonds between the sulfide and the Ferric MGDA to form elemental sulfur mixed with a re-activated solution comprising re-activated Ferric MGDA;

separating the elemental sulfur from the re-activated solution to form a substantially hydrogen-sulfide-free solution; and

re-cycling the substantially sulfide-free solution to serve as the clean aqueous solution.

2. The method of claim 1 , wherein:

the common vessel is an atmospheric vessel.

3. The method of claim 1 , further comprising:

repeating the first plurality of activities.

4. The method of claim 1 , further comprising:

repeating the first plurality of activities without introducing additional Ferric MGDA to the clean aqueous solution.

5. The method of claim 1 , wherein the first plurality of activities further comprises:

causing flow of the aerobic contaminated gas stream into the common vessel.

6. The method of claim 1 , wherein:

said contacting comprises bubbling the aerobic contaminated gas stream through the clean aqueous solution.

7. The method of claim 1 , wherein:

said contacting comprises blowing the aerobic contaminated gas stream into the clean aqueous solution.

8. The method of claim 1 , wherein:

said contacting comprises spraying the clean aqueous solution into the aerobic contaminated gas stream.

9. The method of claim 1 , wherein:

said contacting comprises dripping the clean aqueous solution into the aerobic contaminated gas stream.

10. The method of claim 1 , wherein:

the clean aqueous solution has a pH of 5.9 or higher.

11. The method of claim 1 , wherein:

the clean aqueous solution has a pH of 8 or higher.

12. The method of claim 1 , wherein:

the oxidant is a peroxide.

13. The method of claim 1 , wherein:

the oxidant is oxygen within the aerobic contaminated gas stream.

14. The method of claim 1 , wherein:

the oxidant is oxygen.

15. The method of claim 1 , wherein:

the oxidant is atmospheric oxygen.

16. A method comprising:

in a substantially aerobic treatment zone of a single vessel, reacting reactants comprising a ferro MGDA and an aerobic contaminated gas stream, the aerobic contaminated gas stream comprising air mixed with hydrogen sulfide, the hydrogen sulfide present at a concentration of at least 5 ppm, wherein:

reaction products of the reacting comprise:

a spent ferro MGDA that comprises iron saturated with sulfide; and

a clean gas stream having a concentration of hydrogen sulfide of no greater than 3.5 ppm;

a content of the treatment zone is actively maintained at a pH of between approximately 5.9 and approximately 10; and

in the single vessel, via a reaction with an oxidant, separating the sulfide and the iron.

17. The method of claim 16 , wherein:

the aerobic contaminated gas stream remains in contact with the ferro MGDA for at least 2.5 seconds.

18. The method of claim 16 , wherein:

the ferro MGDA is recirculated at a rate of at least 0.055 gallons of ferro MGDA per cubic foot of the aerobic contaminated gas stream.