Method for remediation of aquifers

Abstract

A method for remediating aquifers and groundwater contaminated, for example by toxic halogenated organic compounds, certain inorganic compounds, and oxidized heavy metals and radionuclides, using the introduction of an innocuous oil, preferably an edible, food grade oil such as soybean oil, formulated into a microemulsion preferably by mixing with a natural food-grade emulsifier (such as lecithin) and water.

1. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
 a) evaluating the aquifer for contaminant identity and location,  
 b) determining whether aquifer pretreatment should be done, and if so, pretreating the aquifer,  
 c) treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms, 
 d) determining whether aquifer post-treatment should be done, and if so, post-treating the aquifer; , and  
 e) monitoring the aquifer to determine if remediation has been accomplished.  
 
     
     
       2. The method according to  claim 1 , wherein the contaminants in the aquifer are selected from the group consisting of halogenated organic compounds, inorganic compounds that may be degraded through anaerobic processes, and soluble compounds that may be immobilized to form insoluble compounds. 
     
     
       3. The method according to  claim 1 , wherein the oil microemulsion comprises a food-grade, slowly soluble, emulsified oil substrate. 
     
     
       4. The method according to  claim 1 , wherein the pretreatment comprises pretreatment of certain portions of the aquifer with a chemical agent selected from the group consisting of agents that reduce sorption of the oil microemulsion by the aquifer material, and agents that reduce entrapment of the oil microemulsion by the aquifer material. 
     
     
       5. The method according to  claim 4 , wherein the chemical agent is an emulsifier. 
     
     
       6. The method of  claim 5 , wherein the emulsifier is lecithin. 
     
     
       7. The method according to  claim 4 , wherein the chemical agent is a salt selected from the group consisting of calcium, sodium and phosphate salts. 
     
     
       8. The method according to  claim 4 , wherein the pretreatment further comprises injecting an oil microemulsion, and then water, after pretreatment with the chemical agent. 
     
     
       9. The method according to  claim 1 , wherein the oil microemulsion comprises an oil selected from the group consisting of soybean oil, corn oil, canola oil, olive oil, peanut oil, coconut oil, palm oil, rape oil, fish oil, butter, and animal tallow. 
     
     
       10. The method according to  claim 9 , wherein the oil is a food-grade liquid soybean oil. 
     
     
       11. The method according to  claim 9 , wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point. 
     
     
       12. The method according to  claim 1 , wherein the selected amount of the oil microemulsion is determined using groundwater velocity, concentration of contaminants and competing electron acceptors, known ratios of oil to other compounds required for biodegradation, a preferred concentration of the oil microemulsion, and a length of time for the treatment to last. 
     
     
       13. The method according to  claim 1 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       14. The method according to  claim 13 , wherein the emulsifier is non-toxic, is capable of forming stable oil-in-water microemulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate. 
     
     
       15. The method according to  claim 13 , wherein the emulsifier is selected from the group consisting of lecithin, milk solids, carrageenan, guar gum, locust bean gum, karaya gum, zanthan gum, pectin, polysorbate, and phosphates. 
     
     
       16. The method according to  claim 15 , wherein the emulsifier is lecithin. 
     
     
       17. The method according to  claim 13 , wherein the ratio of emulsifier to oil in the oil microemulsion is about 1:3 to 1:10. 
     
     
       18. The method according to  claim 1 , wherein the oil microemulsion is mixed with water. 
     
     
       19. The method according to  claim 18 , wherein the ratio of oil microemulsion to water is about 1:3 to 1:10. 
     
     
       20. The method according to  claim 1 ,  A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a) evaluating the aquifer for contaminant identity and location,    
   b) determining whether aquifer pretreatment should be done, and if so, pretreating the aquifer,    
   c) treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment,  wherein the aquifer is treated using a permeable reactive barrier perpendicular to flow and transport of dissolved groundwater contamination in the aquifer.,  
 d) determining whether aquifer post-treatment should be done, and if so, post-treating the aquifer, and  
   e) monitoring the aquifer to determine if remediation has been accomplished .  
 
     
     
       21. The method according to  claim 20   A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a) evaluating the aquifer for contaminant identity and location,    
   b) determining whether aquifer pretreatment should be done, and if so, pretreating the aquifer,    
   c) treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the aquifer is treated using a permeable reactive barrier perpendicular to flow and transport of dissolved groundwater contamination in the aquifer,    
   d )  determining whether aquifer post-treatment should be done, and if so, post-treating the aquifer, and    
   e) monitoring the aquifer to determine if remediation has been accomplished, .  wherein the monitoring comprises collecting data indicating that: (1) the contaminants are degraded to required levels; (2) there is little bypassing of contaminants around the barrier; (3) the permeability changes in the aquifer surrounding the injection wells are within acceptable ranges; and (4) there are acceptable rates of substrate depletion in the barrier.  
 
     
     
       22. The method according to  claim 1 , wherein the contaminant is from a source area and is in a plume having an areal extent, and the aquifer is treated by distributing the oil microemulsion across the areal extent of the plume or source area to effect an immediate remediation throughout the aquifer. 
     
     
       23. The method according to  claim 1 , wherein the aquifer is treated by injecting the oil microemulsion through an end of a direct push point as the push point is withdrawn, forming a borehole, using injection flow rates adjusted to ensure that there is at least 10 psi of pressure buildup in the borehole. 
     
     
       24. The method according to  claim 1 , wherein the aquifer is treated by injecting the oil microemulsion using a temporary well installed in a borehole. 
     
     
       25. The method according to  claim 1 , wherein the aquifer is treated with the oil microemulsion in injection wells using injection flow rates adjusted to ensure that there is at least 10 psi of pressure buildup in each injection well. 
     
     
       26. The method according to  claim 1 , wherein post-treatment of the aquifer comprises a post-treatment pulse of emulsifier. 
     
     
       27. The method according to  claim 26 , further comprising addition of water to the aquifer. 
     
     
       28. The method according to  claim 1 , wherein said oil microemulsion acts as a carbon substrate and an electron donor. 
     
     
       29. The method according to  claim 1 , wherein said oil microemulsion acts as a carbon substrate. 
     
     
       30. The method according to  claim 1 , wherein said oil microemulsion acts as an electron donor. 
     
     
       31. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms. 
     
     
       32. The method according to  claim 31 , wherein the oil microemulsion comprises an edible oil. 
     
     
       33. The method according to  claim 31 , wherein the microemulsion is an emulsion having an average droplet size of approximately  1  micron in diameter. 
     
     
       34. The method according to  claim 31 , wherein the microemulsion is an emulsion having an average droplet size that does not exceed approximately  1  micron in diameter. 
     
     
       35. The method according to  claim 28 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       36. The method according to  claim 35 , wherein the emulsifier is non- toxic, is capable of forming oil - in - water emulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate.   
     
     
       37. The method according to  claim 35 , wherein the ratio of emulsifier to oil in the oil microemulsion is about  1 : 3  to  1 : 10 . 
     
     
       38. The method according to  claim 31 , wherein said oil microemulsion acts as a carbon substrate and electron donor. 
     
     
       39. The method according to  claim 31 , wherein said oil microemulsion acts as a carbon substrate. 
     
     
       40. The method according to  claim 31  wherein said oil microemulsion acts as an electron donor. 
     
     
       41. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point. 
     
     
       42. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  creating an emulsified mixture comprised of oil, water, and one or more emulsifiers, wherein said mixture has a mean droplet size less than the mean pore size of the sediment, and in which the emulsified mixture acts to stimulate the growth of microorganisms, and        b )  injecting said mixture into the aquifer.     
     
     
       43. The method according to  claim 42 , wherein the oil is an edible oil. 
     
     
       44. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  evaluating the aquifer for contaminant identity and location,        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms, and        c )  monitoring the aquifer to determine if remediation has been accomplished.     
     
     
       45. The method according to  claim 44 , wherein the oil microemulsion comprises an edible oil. 
     
     
       46. The method according to  claim 44 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       47. The method according to  claim 46 , wherein the emulsifier is non-toxic, is capable of forming oil-in-water microemulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate. 
     
     
       48. The method according to  claim 46 , wherein the ratio of emulsifier to oil in the oil microemulsion is about  1 : 3  to  1 : 10 . 
     
     
       49. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  evaluating the aquifer for contaminant identity and location,        b) treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point, and        c) monitoring the aquifer to determine if remediation has been accomplished.     
     
     
       50. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  evaluating the aquifer for contaminant identity and location, and        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms.     
     
     
       51. The method according to  claim 50 , wherein the oil microemulsion comprises an edible oil. 
     
     
       52. The method according to  claim 50 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       53. The method according to  claim 52 , wherein the emulsifier is non-toxic, is capable of forming stable oil-in-water microemulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate. 
     
     
       54. The method according to  claim 52 , wherein the ratio of emulsifier to oil in the oil microemulsion is about  1 : 3  to  1 : 10 . 
     
     
       55. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  evaluating the aquifer for contaminant identity and location, and        b) treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point.     
     
     
       56. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, consisting essentially of treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point. 
     
     
       57. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, consisting essentially of:
   a )  evaluating the aquifer for contaminant identity and location,        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms, and        c )  monitoring the aquifer to determine if remediation has been accomplished.     
     
     
       58. The method according to  claim 57 , wherein the oil microemulsion comprises an edible oil. 
     
     
       59. The method according to  claim 57 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       60. The method according to  claim 59 , wherein the emulsifier is non- toxic, is capable of forming stable oil - in - water microemulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate.   
     
     
       61. The method according to  claim 59 , wherein the ratio of emulsifier to oil in the oil microemulsion is about  1 : 3  to  1 : 10 . 
     
     
       62. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, consisting essentially of:
   a )  evaluating the aquifer for contaminant identity and location,        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point, and        c )  monitoring the aquifer to determine if remediation has been accomplished.     
     
     
       63. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, consisting essentially of:
   a )  evaluating the aquifer for contaminant identity and location, and        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms.     
     
     
       64. The method according to  claim 63 , wherein the oil microemulsion comprises an edible oil. 
     
     
       65. The method according to  claim 63 , wherein the oil microemulsion is formed using an emulsifier. 
     
     
       66. The method according to  claim 65 , wherein the emulsifier is non- toxic, is capable of forming stable oil - in - water microemulsions under the environmental conditions present at the aquifer site, and is characterized in that its sorption and attachment to the sediment in the aquifer can be controlled to move through the aquifer at a desired rate.   
     
     
       67. The method according to  claim 65 , wherein the ratio of emulsifier to oil in the oil microemulsion is about  1 : 3  to  1 : 10 . 
     
     
       68. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, consisting essentially of:
   a )  evaluating the aquifer for contaminant identity and location, and        b )  treating the aquifer with a selected amount of an oil microemulsion having an average droplet size less than the mean pore size of the sediment, wherein the oil has been modified by hydrogenation to reduce aqueous solubility and increase melting point.     
     
     
       69. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising treating the aquifer with a selected amount of an edible oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms. 
     
     
       70. A method for remediating a selected aquifer in a sediment having a mean pore size to reduce contaminants in the aquifer, comprising:
   a )  evaluating the aquifer for contaminant identity and location,        b )  treating the aquifer with a selected amount of an edible oil microemulsion having an average droplet size less than the mean pore size of the sediment, and in which the oil microemulsion acts to stimulate the growth of microorganisms, and        c )  monitoring the aquifer to determine if remediation has been accomplished.