METHOD FOR EXTRACTION AND SURFACTANT ENHANCED SUBSURFACE CONTAMINANT RECOVERY

• US 20100185039A1
• Filed: 09/26/2008
• Published: 07/22/2010
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Ethical Solutions, LLC
• Original Assignee: Vertex Technologies Private Limited (Temasek Holdings Pte Ltd. (Investment Management))
• Inventors: Anderson, Douglas K., Hoag, George E., Collins, John B.
• Granted Patent: US 9,895,730 B2
• Time in Patent Office: Days
• US Class Current: 588/320
• CPC Class Codes: B09C 1/00 Reclamation of contaminated soil
• CPC Class Codes: B09C 1/002 involving in-situ ground water treatment
• CPC Class Codes: B09C 1/02 Extraction using liquids, e.g. washing, leaching , flotation
• CPC Class Codes: B09C 1/08 chemically

Abstract

Methods and compositions for removing contaminants from soil and groundwater by extracting the contaminants and assisting the extraction by provision of an oxidant introduced prior to or simultaneously with a surfactant into the subsurface. Extractable contaminant can be extracted from the subsurface. The amount and/or distribution of contaminant in the subsurface can be characterized. The extracting of contaminant and the introducing of oxidant and surfactant can be coordinated to reduce contaminant to a target amount. A portion of the contaminant can be oxidizable.

Claims

1. A method for decreasing the amount of contaminant at a site in a subsurface, wherein at least a portion of the contaminant is extractable, comprising:

introducing an oxidant prior to or simultaneously with a surfactant into the subsurface;

extracting extractable contaminant from the subsurface;

characterizing the amount and/or distribution of contaminant in the subsurface;

coordinating the extracting of contaminant and the introducing of oxidant and surfactant to reduce contaminant to a target amount.

2. The method of claim 1,

allowing the oxidant to liberate gaseous oxygen in the subsurface in the form of bubbles;

and

allowing the oxygen bubbles to hydrodynamically scrub contaminant from soil particles in the subsurface.

3. The method of claim 2, wherein the oxidant comprises hydrogen peroxide.

4. The method of claim 3, wherein the hydrogen peroxide is introduced into the subsurface at a concentration of from about 2 wt % to about 16 wt %.

5. The method of claim 3, wherein the hydrogen peroxide is introduced into the subsurface at a concentration of from about 4 wt % to about 10 wt %.

6. The method of claim 3, wherein the hydrogen peroxide is introduced into the subsurface at a concentration of about 8 wt %.

7. The method of claim 2, wherein the oxidant comprises oxygen dissolved in a fluid.

8. The method of claim 2, wherein the oxidant decomposes to liberate gaseous oxygen.

9. The method of claim 2, wherein the oxidant comprises oxygen dissolved in a fluid, and the oxygen effervesces from the fluid to liberate gaseous oxygen.

10. The method of claim 2, wherein the oxidant decomposes and/or the contaminant oxidizes to liberate heat.

11. The method of claim 10, wherein the liberated heat increases the temperature of the contaminant, so that the viscosity of the contaminant is decreased and the contaminant is extracted at a greater rate.

12. The method of claim 10, wherein the liberated heat increases the temperature of the contaminant, so that the oxidant more rapidly oxidizes the contaminant.

13. The method of claim 2, further comprising allowing the oxidant to oxidize the contaminant to lower the molecular weight of the contaminant and/or render the contaminant more amenable to microbial degradation.

14. The method of claim 13, wherein the lowering of the molecular weight of the contaminant decreases the viscosity of the contaminant, so that the contaminant is extracted at a greater rate.

15. The method of claim 2, wherein the contaminant is extracted from the subsurface through an extraction well, and the surfactant is introduced as a fluid into the subsurface at an injection locus.

16. The method of claim 15, wherein the fluid flows from the injection locus through the subsurface to the extraction well at a mean velocity of at least about 0.01 cm/hour, 0.1 cm/hour, at least about 1 cm/hour, at least about 3 cm/hour, at least about 10 cm/hour, at least about 30 cm/hour, at least about 100 cm/hour, or at least about 300 cm/hour.

17. The method of claim 15, wherein the fluid is flowed through the subsurface for a period of time of at least about equal to, at least about 3 times, at least about 10 times, at least about 30 times, at least about 100 times, at least about 300 times, or at least about 1000 times the mean time for a fluid element of the fluid to flow from the injection locus to the extraction well.

18. The method of claim 2, wherein a mixture in the subsurface comprising the contaminant and the surfactant has an interfacial tension of at least the interfacial tension associated with the critical micelle concentration of the surfactant.

19. The method of claim 1, further comprising introducing the oxidant and the surfactant into the subsurface while not extracting contaminant from the subsurface;

20. The method of claim 1, further comprising:

selecting a remediation zone including the contaminant;

allowing the oxidant to establish an oxidation zone in the subsurface;

providing an extraction well; and

inducing the flow of contaminant toward the extraction well to establish an extraction zone,

wherein the oxidation zone and the extraction zone lie within the remediation zone, and the oxidation zone prevents spread of the contaminant beyond the remediation zone.

21. The method of claim 20, wherein the molar concentration of oxygen atoms in the oxidation zone is in the range of from about 0.015 to about 8 mol/L.

22. The method of claim 20, wherein the molar concentration of oxygen atoms in the oxidation zone is in the range of from about 1 to about 4 mol/L.

23. The method of claim 20, comprising applying a partial or full vacuum to the extraction well to induce the flow of contaminant toward the extraction well.

24. The method of claim 20, comprising pumping contaminant out of the extraction well to induce the flow of contaminant toward the extraction well.

25. The method of claim 20, comprising introducing the oxidant and/or surfactant into the subsurface under pressure to induce the flow of contaminant toward the extraction well.

26. The method of claim 20,

wherein the contaminant migrates downgradient along streamlines that pass through the contaminated site and

wherein the oxidation zone intercepts the streamlines that pass through the contaminated site.

27. The method of claim 20, wherein the oxidation zone encloses the remediation zone.

28. The method of claim 20, wherein the oxidation zone encloses the extraction zone.

29. The method of claim 20,

wherein the subsurface includes a stratum impermeable to the contaminant and

wherein the oxidation zone in conjunction with the impermeable stratum prevents spread of the contaminant beyond the remediation zone.

30. The method of claim 20, wherein the oxidant is introduced into the subsurface at an injection locus, and wherein the injection locus is the extraction well.

31. The method of claim 20,

wherein the oxidant is introduced into the subsurface in an injection well, and

wherein a plurality of extraction wells surrounds the injection well.

32. The method of claim 20,

wherein the oxidant is introduced into the subsurface through a plurality of injection wells, and

wherein the plurality of injection wells surrounds the extraction well.

33. The method of claim 20, wherein the surfactant is injected through a plurality of wells surrounding the extraction zone.

34. The method of claim 20, wherein the surfactant is injected through a well within the extraction zone.

35. The method of claim 20, wherein the surfactant is injected through a well upgradient of the contaminated site.

36. The method of claim 20,

wherein the oxidation zone encloses the extraction zone and

wherein the oxidation zone encloses a region where the surfactant is injected through a well.

37. The method of claim 20, wherein the surfactant is injected through a well within the oxidation zone.

38. The method of claim 20, further comprising determining a hydrogeological property of the subsurface.

39. The method of claim 38, wherein the hydrogeological property is selected from the group consisting of a physical property, a chemical property, water saturated zones, water unsaturated zones, hydraulic gradient, saturated thickness, soil composition, hydraulic conductivity, porosity, density, and variation of any of these with time and/or space.

40. The method of claim 38, further comprising:

determining the spatial concentration distribution of the target contaminant; and

using the hydrogeological property to determine an optimal location of an injection locus for introducing the oxidant, an optimal location of an injection locus for introducing the surfactant, and/or an optimal location of the extraction well.

41. The method of claim 1, wherein the surfactant is biodegradable.

42. The method of claim 1, wherein the surfactant is a naturally occurring or is made from a naturally occurring plant extract.

43. The method of claim 1, wherein the surfactant is or is made from a carboxylate ester, a plant-based ester, a terpene, a citrus-derived terpene, limonene, d-limonene, or combinations of these.

44. The method of claim 1, wherein the surfactant is or is made from castor oil, coca oil, coconut oil, soy oil, tallow oil, cotton seed oil, a naturally occurring plant oil, or combinations of these.

45. The method of claim 1, wherein the surfactant is or is made from a nonionic surfactant, ethoxylated soybean oil, ethoxylated castor oil, ethoxylated coconut fatty acid, amidified, ethoxylated coconut fatty acid, or combinations of these.

46. The method of claim 1, wherein the surfactant is selected from the group consisting of ALFOTERRA 123-8S, ALFOTERRA 145-8S, ALFOTERRA L167-7S, ETHOX HCO-5, ETHOX HCO-25, ETHOX CO-5, ETHOX CO-40, ETHOX ML-5, ETHAL LA-4, AG-6202, AG-6206, ETHOX CO-36, ETHOX CO-81, ETHOX CO-25, ETHOX TO-16, ETHSORBOX L-20, ETHOX MO-14, S-MAZ 80K, T-MAZ 60 K 60, TERGITOL L-64, DOWFAX 8390, ALFOTERRA L167-4S, ALFOTERRA L123-4S, ALFOTERRA L145-4S, Alfoterra 53, Citrus Burst 1, Citrus Burst 2, Citrus Burst 3, E-Z Mulse, and combinations of these.

47. The method of claim 1, wherein the surfactant is introduced into the subsurface at a concentration of from about 1 g/L to about 100 g/L.

48. The method of claim 1, wherein the surfactant is introduced into the subsurface at a concentration of from about 10 g/L to about 25 g/L.

49. The method of claim 1, wherein the surfactant comprises VeruSOL™

.

50. The method of claim 49, wherein the surfactant comprises VeruSOL-3™

, VeruSOL-9™

, and/or VeruSOL-10™

.

51. The method of claim 1, wherein the oxidant is selected from the group consisting of a persulfate, sodium persulfate, a percarbonate, a peroxide, hydrogen peroxide, ozone, oxygen, and combinations of these.

52. The method of claim 1, wherein the oxidant comprises sodium persulfate, and the sodium persulfate is introduced to the subsurface at a concentration of from about 50 g/L to about 100 g/L.

53. The method of claim 1, wherein the oxidant is introduced in the solid phase and/or in an aqueous solution.

54. The method of claim 1, further comprising introducing sodium bicarbonate into the subsurface.

55. The method of claim 54, wherein the sodium bicarbonate is introduced into the subsurface at a concentration of from about 5 g/L to about 80 g/L.

56. The method of claim 54, wherein the sodium bicarbonate is introduced into the subsurface at a concentration of about 20 g/L.

57. The method of claim 1, further comprising introducing an activator into the subsurface.

58. The method of claim 57, wherein the activator is introduced at a concentration of from about 100 mg/L to about 2000 mg/L into the subsurface.

59. The method of claim 57, wherein the activator is introduced at a concentration of about 400 mg/L into the subsurface.

60. The method of claim 1, further comprising introducing an activator into the subsurface selected from the group consisting of a metal, a chelated metal, chelated iron, Fe-NTA, Fe(II)-EDTA, Fe(III)-EDTA, Fe(II)-citric acid, Fe(III)-citric acid, Fe(II)-EDDS, Fe(III)-EDDS, Fe(II)-DTPA, and Fe(III)-DTPA.

61. The method of claim 1, further comprising introducing heat as an activator into the subsurface.

62. The method of claim 1, further comprising introducing a base or caustic chemical as an activator into the subsurface, wherein a region of the subsoil in which the contaminant is present has a pH greater than 10.5

63. The method of claim 1, further comprising introducing an antioxidant into the subsurface.

64. The method of claim 1, wherein the introduction of the oxidant and the surfactant and the extraction of the contaminant proceed sequentially.

65. The method of claim 1, wherein the introduction of the oxidant and the surfactant and the extraction of the contaminant proceed simultaneously.

66. The method of claim 1, further comprising monitoring the concentration and/or spatial distribution of the oxidant, surfactant, and contaminant, and/or products of contaminant oxidation in the subsurface.

67. The method of claim 1, wherein the contaminant comprises a non-aqueous phase liquid (NAPL), a dense non-aqueous phase liquid (DNAPL), and/or a light non-aqueous phase liquid (LNAPL).

68. The method of claim 1, wherein the oxidant and surfactant are introduced into the subsurface as a liquid, an aqueous solution, a supercritical fluid solution, or a solution in supercritical carbon dioxide.

69. The method of claim 1, wherein the oxidant and/or the surfactant is introduced to the subsurface by using equipment selected from a backhoe, excavator, soil mixing auger, mixing jet, and windrow composting type above ground mixer.

70. The method of claim 1, wherein the oxidant and/or the surfactant is introduced to the subsurface through an injection well, an injection trench, a temporary injection point, an infiltration gallery, a monitoring well, being sprayed on a surface, being added as a concentrated slurry to subsurface, and/or being added as a solid phase to the subsurface.

71. The method of claim 1, wherein the oxidant and/or the surfactant is introduced through pressurized injection or non-pressurized injection.

72. The method of claim 1, further comprising emplacing fractures in the subsurface, wherein the oxidant and/or the surfactant is introduced through the fractures emplaced in the subsurface.

73. The method of claim 1, wherein the oxidant and/or the surfactant is introduced through fractures existing in bedrock at the site.

74. The method of claim 1, further comprising dissolving a salt in a fluid comprising the oxidant and/or surfactant to increase the density of the introduced fluid.

75. The method of claim 1, wherein a mixture in the subsurface comprising the contaminant and the surfactant has an interfacial tension of at least the interfacial tension associated with the critical micelle concentration of the surfactant.

76. The method of claim 1, further comprising allowing the surfactant to solubilize and/or desorb contaminant.

77. The method of claim 1, further comprising allowing the oxidant to oxidize contaminant.

78. The method of claim 1, further comprising:

allowing the surfactant to solubilize and/or desorb contaminant; and

allowing the oxidant to oxidize contaminant,

wherein an overall rate of oxidization of contaminant is controlled to a predetermined value and an overall rate of solubilization of contaminant is controlled to a predetermined value by selecting the oxidant and surfactant and adjusting the concentrations of oxidant and surfactant, so that the rate of oxidation of contaminant is greater than, less than, or equal to the rate of solubilization of contaminant.

79. A method of designing a procedure for decreasing the amount of a contaminant at a site in a subsurface, comprising:

obtaining a sample from the contaminated site or composing a simulated or analogous sample;

testing the sample with various concentrations of oxidant and surfactant under various conditions of temperature, pressure, and flow rate of oxidant and surfactant;

determining the rate of mobilization of the contaminant under the various conditions; and

selecting optimum oxidant and surfactant for introduction into the subsurface, optimum concentrations of oxidant and surfactant for injection into the subsurface, and optimum temperature, pressure, and flow rate conditions for decreasing the amount of the contaminant at the site in the subsurface.

80. The method of claim 79, wherein if the at least one target contaminant resides above the water table, then the optimum oxidant and surfactant and the optimum concentrations of oxidant and surfactant for introduction into the subsurface are selected so that the density of an introduced fluid comprising the oxidant and/or surfactant is less than 1 gram/cm³.

81. The method of claim 79, wherein if the at least one target contaminant resides below the water table, then the optimum oxidant and surfactant and the optimum concentrations of oxidant and surfactant for introduction into the subsurface are selected so that the density of an introduced fluid comprising the oxidant and/or surfactant is greater than 1 gram/cm³.

82. The method of claim 79, wherein if the at least one target contaminant resides at about the same level as the water table, then the optimum oxidant and surfactant and the optimum concentrations of oxidant and surfactant for introduction into the subsurface are selected so that the density of an introduced fluid comprising the oxidant and/or surfactant is about 1 gram/cm³.

83. The method of claim 79, further comprising

determining the spatial concentration distribution of the target contaminant;

determining a hydrogeological property of the subsurface; and

using the determined spatial concentration distribution of the target contaminant and the hydrogeological property to determine an optimal target depth for the oxidant and/or surfactant, an optimal injection locus for the oxidant and/or surfactant, and/or an optimal extraction locus for the contaminant.

84. The method of claim 83, further comprising selecting a non-oxidant, non-activator salt for introduction into the subsurface with the oxidant and/or surfactant to maximize the fraction of the oxidant and/or surfactant that remains at the optimal target depth.