Thixotropic gel for vadose zone remediation
View Patent ↗A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.
1. A process of bioremediation within a vadose zone comprising:
identifying a vadose zone contaminant area;
creating a thixotropic injectable solution comprising a mixture of an edible oil, water, and fumed silica;
agitating said thixotropic injectable solution, thereby enabling said thixotropic injectable solution to be injected under pressure to a subsurface vadose zone;
injecting said thixotropic solution into said vadose zone, said injectable solution thereby forming a non-migrating gel within said vadose zone;
wherein said non-migrating gel establishes an in situ anaerobic environment in response to biological colonization within said non-migrating gel.
2. The process according to claim 1 wherein said step of creating a thixotropic injectable solution further comprises sparging the solution with nitrogen gas.
3. The process according to claim 1 wherein said step of creating a thixotropic injectable solution further provides for the additional step of removing free oxygen from said thixotropic injectable solution.
4. The process according to claim 1 wherein said step of creating a thixotropic injectable solution further comprises the additional step of introducing at least one bacterial strain adapted for in situ bioremediation in a subsurface soil environment.
5. A process of remediating volatile organic compounds within a vadose zone comprising:
injecting a thixotropic material into a vadose zone contaminated with volatile organic compounds, said thixotropic material comprising a biodegradable oil;
sequestering within said biodegradable oil said volatile organic compounds present within the vadose zone;
establishing anaerobic conditions within said thixotropic material; and,
degrading said volatile organic compounds by the metabolic activity of bacteria present within said thixotropic material.
6. The process according to claim 5 wherein said thixotropic gel is non-migratory following injection into the vadose zone.
7. The process according to claim 5 wherein said bacteria are native populations present within the vadose zone.
8. The process according to claim 5 wherein said bacterial further include bacterial strains which are introduced into said thixotropic material prior to injection.
9. A process of remediating heavy metals from subsurface soils comprising:
injecting a thixotropic material into a subsurface region contaminated with heavy metals, said thixotropic material comprising a biodegradable oil;
sequestering within said thixotropic material heavy metals from said surrounding soil; and,
establishing conditions within said thixotropic material in proximity to said sequestered heavy metals wherein said heavy metals are treated by at least one of a treatment step selected from the group consisting of chelating said heavy metal, metabolizing said heavy metal, oxidizing said heavy metal, reducing said heavy metal, binding said heavy metal to a non-migratory substrate, and combinations thereof.