In situ alkaline hydrolysis of subsurface contaminants using gaseous reactants

Patent metadata

Field	Value
Publication number	US-9511399-B2
Application number	US-201514692210-A
Country	US
Kind code	B2
Filing date	Apr 21, 2015
Priority date	Apr 21, 2015
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

The present invention includes methods and a system for treating a mass of contaminated media using ammonia. The methods include determining the amount of ammonia required for treatment using various calculation methods and combining the ammonia with air or another carrier gas to create a gas mixture. The methods and system utilize at least one injection well inserted into the contaminated media to deliver the gas mixture over a period ranging from approximately 1 week to approximately 8 weeks.

First claim

What is claimed is:

1. A method for treating a mass of contaminated media, comprising the steps of:
removing a sample of said contaminated media;
testing said sample to determine a current pH level P A and a current lime buffering capacity B L of said contaminated media;
calculating a quantity M of said ammonia needed for treatment of said contaminated media using the equation
M =( P D −P A )* A C *F*B L
wherein P D is a desired pH of said contaminated media, A C is a constant value of approximately 0.34 milligrams of said ammonia per milligram of calcium carbonate, F is a safety factor of approximately 10.4;

inserting said at least one injection well into said contaminated media;
creating a gas mixture by combining said quantity M of said ammonia with air and/or carrier gas; and
delivering said gas mixture over a period ranging from approximately 1 week to approximately 8 weeks.

2. The method of claim 1 , further comprising the step of performing hydraulic or pneumatic fracturing of said contaminated media before delivering said gas mixture.

3. The method of claim 1 , further comprising the step of modifying a structure of said contaminated media to allow insertion of said at least one injection well before inserting said at least one injection well.

4. The method of claim 1 , wherein said at least one injection well comprises a plurality of injection wells.

5. The method of claim 4 , wherein said method further comprises the step of selecting a distribution of said plurality of injection wells based on a pneumatic permeability K of said contaminated media calculated using the equation

K
=

Q
*

P
*

*
μ

π
*
b

⁢

ln
⁡

(

r
2

/

r
1

)

P
1
2

-

P
2
2

wherein Q is the volumetric flow rate, P* is the pressure at the point of flow measurement, μ is the viscosity of air, b is the vertical thickness of said contaminated media, r 1 and r 2 are the distance to observation points and P 1 and P 2 are the absolute pressures at observation points.

6. The method of claim 1 , further comprising the step of increasing a temperature of said contaminated media.

7. The method of claim 6 , wherein said temperature of said contaminated media increases to a final temperature ranging from approximately 20 degrees Celsius to approximately 70 degrees Celsius.

8. The method of claim 1 , further comprising the step of increasing a moisture content of said contaminated media.

9. The method of claim 8 , wherein said moisture content of said contaminated media increases to a final moisture content ranging from approximately 5% to a point below saturation of said contaminated media.

10. The method of claim 1 , wherein said ammonia makes up approximately 4% to approximately 14% of said gas mixture.

11. The method of claim 1 , wherein said ammonia makes up approximately 14% to approximately 28% of said gas mixture.

12. The method of claim 1 , wherein said ammonia makes up more than approximately 28% of said gas mixture.

13. The method of claim 1 , further comprising the step of waiting for a period of approximately 2 weeks to approximately 6 weeks for completion of any chemical reactions in said contaminated media.

14. The method of claim 1 , further comprising the step of retesting said current pH level of said contaminated media.

15. The method of claim 1 , wherein said contaminated media comprises soil.

16. The method of claim 15 , wherein said soil is in the vadose zone.

17. The method of claim 1 , wherein said contaminated media comprises groundwater.

18. The method of claim 17 , wherein said groundwater is perched water.

19. A method for treating a mass of contaminated media, comprising the steps of:
removing a sample of said contaminated media;
administering a known quantity M T of ammonia to said sample of said contaminated media by injecting said known quantity of ammonia through said sample of said contaminated media;
testing said sample of said contaminated media to determine a current pH P A of said sample of said contaminated media;
calculating a quantity of ammonia M needed for treatment of said contaminated media using the equation

M
=

M
T

*

M
C

*

(

P
D

-

P
A

)

M
S

*

(

P
D

-

P
A

)

wherein M C is a mass of said contaminated media to be treated, P D is a desired pH of said contaminated media, and M S is a mass of the sample of contaminated media;

inserting said at least one injection well into said contaminated media;
creating a gas mixture of said ammonia with air and/or carrier gas; and
delivering said gas mixture over a period ranging from approximately 1 week to approximately 8 weeks.

Assignees

• Coyle Charles G
• Medina Victor F
• Waisner Scott A
• Mao Chung-Rei
• Us Army

Inventors

• Coyle Charles G
• Medina Victor F
• Waisner Scott A
• Mao Chung-Rei

Classifications

• C02F1/66

  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 title

• G01N33/24

  Earth materials (G01N33/42 takes precedence) · CPC title

• B09C1/002

  involving in-situ ground water treatment · CPC title

• C02F2103/06

  Contaminated groundwater or leachate · CPC title

• B09C2101/00

  In situ · CPC title