Method of in situ decontamination
First Claim
1. A process for removing contaminants from a vadose zone above a water table having a capillary fringe comprising the steps of:
- establishing a borehole into the vadose zone and into at least the top of the capillary fringe of the water table;
introducing a porous fill material into the borehole and positioning the fill material adjacent to portions of the vadose zone containing the contaminant;
positioning one end of a hollow conduit having a solid, air impermeable side wall into the borehole, the conduit having its other end connected to pump means capable of applying suction to the conduit;
sealing an upper portion of the borehole around the conduit from the atmosphere;
applying suction to the conduit and the borehole to reduce pressure in portions of the vadose zone and cause
1) air and contaminant vapors to move through the vadose zone and along the top of the capillary fringe and into the borehole and
2) creation of a liquid-vapor contaminant concentration gradient in the vadose zone and along the top of the capillary fringe to facilitate vaporization of liquid contaminant and movement of the vapor through the vadose zone into the borehole; and
removing air and contaminant vapors from the borehole.
7 Assignments
0 Petitions
Accused Products
Abstract
A method of removing volatile contaminants from a layer of contaminant lying on the top of a water table and in an unsaturated zone including opening a hole into the unsaturated zone and downwardly to at least the top of the layer of contaminant, positioning the end of a solid, air impermeable hollow pipe into the hole and adjacent to air permeable fill material, establishing an airtight seal around the pipe at the hole, reducing the pressure in the pipe in the hole to cause air and contaminant vapors to flow along the layer of contaminant and through the unsaturated zone and into the hole and through the air permeable fill material, and removing air and contaminant vapors from the hole through the pipe.
40 Citations
20 Claims
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1. A process for removing contaminants from a vadose zone above a water table having a capillary fringe comprising the steps of:
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establishing a borehole into the vadose zone and into at least the top of the capillary fringe of the water table; introducing a porous fill material into the borehole and positioning the fill material adjacent to portions of the vadose zone containing the contaminant; positioning one end of a hollow conduit having a solid, air impermeable side wall into the borehole, the conduit having its other end connected to pump means capable of applying suction to the conduit; sealing an upper portion of the borehole around the conduit from the atmosphere; applying suction to the conduit and the borehole to reduce pressure in portions of the vadose zone and cause
1) air and contaminant vapors to move through the vadose zone and along the top of the capillary fringe and into the borehole and
2) creation of a liquid-vapor contaminant concentration gradient in the vadose zone and along the top of the capillary fringe to facilitate vaporization of liquid contaminant and movement of the vapor through the vadose zone into the borehole; andremoving air and contaminant vapors from the borehole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of removing one or more volatile contaminants from the top of a water table having a capillary fringe and an unsaturated zone comprising:
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excavating a hole downwardly at least to the capillary fringe; inserting one end of a solid wall, air impermeable hollow pipe into the hole to a desired depth; filling at least a portion of the hole with an air permeable fill material; establishing a substantially airtight seal around the pipe at an upper portion of the hole; creating a reduced pressure atmosphere in the pipe and the hole to cause air and vapor phase contaminant to flow along the top of the capillary fringe and the unsaturated zone and into the hole and the pipe; and removing air and the vapor phase contaminant from the hole. - View Dependent Claims (14, 15, 16, 18, 19, 20)
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17. A method of removing volatile contaminant from a layer of contaminant lying on the top of a water table and in an unsaturated zone comprising:
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opening a hole into the unsaturated zone and downwardly to at least the top of the layer of contaminant; positioning an end of a solid wall, air impermeable hollow pipe into the hole and adjacent to air permeable fill material; establishing an airtight seal around the pipe at the hole; reducing the pressure in the pipe and the hole to cause air and contaminant vapors to flow along the layer of contaminant and through the unsaturated zone and into the hole and through the air permeable material; and removing air and contaminant vapors from the hole through the pipe.
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Specification