Removal of volatile contaminants from the vadose zone of contaminated ground

• US 4,593,760 A
• Filed: 01/04/1984
• Issued: 06/10/1986
• Est. Priority Date: 01/04/1984
• Status: Expired due to Term

• Current Assignee: James J. Malot
• Original Assignee: The Upjohn Company (Pharmacia Corp.)
• Inventors: Malot, James J., Visser, Melvin J.
• Primary Examiner(s): Novosad, Stephen J.
• Assistant Examiner(s): Kisliuk, Bruce M.
• Application Number:
  US06/567,972
• Time in Patent Office: 888 Days
• Field of Search: 166/267, 166/268, 166/369, 166/278, 166/370, 166/313
• US Class Current: 166/267
• CPC Class Codes: B09C 1/005 Extraction of vapours or gases using vacuum or venting
• CPC Class Codes: E03B 3/12 by means of vertical pipe wells
• CPC Class Codes: E21B 43/00 Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells applicable only to water E03B
• CPC Class Codes: E21B 43/04 Gravelling of wells
• CPC Class Codes: E21B 43/38 in the well
• CPC Class Codes: Y02A 20/00 Water conservation; Efficient water supply; Efficient water use

Abstract

Volatile contaminants are removed from the vadose zone of contaminated ground by pumping volatilized contaminants from the vadose zone using one or more vacuum extraction wells.

Claims

1. A process for removing a not-naturally-occurring, volatile liquid contaminant from a contaminated area of the earth, wherein the contaminated area of the earth has a subsurface water table and a subsurface vadose zone above the water table, the contaminant being present in the vadose zone, which comprises the steps of:

establishing a borehole extending downwardly from the surface of the ground within the contaminated area;

placing a first conduit within said borehole so that a ring-shaped zone is formed between the wall of said borehole and said conduit, said conduit having a perforate lower portion located in the vadose zone and spaced vertically above the water table so that fluids can flow from the vadose zone into the interior of said conduit, said perforate lower portion having an upper end and a lower end, said conduit having an imperforate upper portion above the upper end of said perforate lower portion,

filling fluid-permeable first fill material into a lower portion of said ring-shaped zone around said perforate lower portion of said conduit and which extends to the upper end of said perforate lower portion so that said first fill material will permit fluid readily to flow into said perforate lower portion of said conduit;

filling a second fill material of low fluid permeability into an upper portion of said ring-shaped zone around said imperforate upper portion of said conduit, said second fill material being effective to impede flow of air from the surface of the ground to the lower portion of the borehole;

applying a vacuum to the upper end of said conduit effective to induce flow of air and a gas containing vapor of said contaminant present in said vadose zone into the lower portion of said conduit and thence to the upper end of said conduit, the vacuum being effective to cause vaporization of a substantial quantity of said contaminant within the vadose zone around the borehole so that said contaminant is removed from the ground in vapor form, and

accumulating liquid in the lower end of said conduit and pumping said liquid to the upper end of said conduit separately from said gas.

2. A process for removing a not-naturally-occurring, volatile liquid contaminant from a contaminated area of the earth, wherein the contaminated area of the earth has a subsurface water table and a subsurface vadose zone above the water table, the contaminant being present in the vadose zone, which comprises the steps of:

establishing a borehole extending downwardly from the surface of the ground within the contaminated area;

placing a first conduit within said borehole so that a ring-shaped zone is formed between the wall of said borehole and said conduit, said conduit having a perforate lower portion located in the vadose zone and spaced vertically above the water table so that fluids can flow from the vadose zone into the interior of said conduit, said perforate lower portion having an upper end and a lower end, said conduit having an imperforate upper portion above the upper end of said perforate lower portion,

filling fluid-permeable first fill material into a lower portion of said ring-shaped zone around said perforate lower portion of said conduit and which extends to the upper end of said perforate lower portion so that said first fill material will permit fluid readily to flow into said perforate lower portion of said conduit;

filling a second fill material of low fluid permeability into an upper portion of said ring-shaped zone around said imperforate upper portion of said conduit, said second fill material being effective to impede flow of air from the surface of the ground to the lower portion of the borehole;

applying a vacuum to the upper end of said conduit effective to induce flow of air and a gas containing vapor of said contaminant present in said vadose zone into the lower portion of said conduit and thence to the upper end of said conduit, the vacuum being effective to cause vaporization of a substantial quantity of said contaminant within the vadose zone around the borehole so that said contaminant is removed from the ground in vapor form,

forming a passageway extending downwardly from the surface of the ground to the vicinity of, but laterally spaced from, said perforate lower portion of said conduit, and

flowing air through said passageway into the vadose zone to increase lateral air flow through the vadose zone into said perforate lower portion of said conduit.

3. A process for removing a not-naturally-occurring, volatile liquid contaminant from a contaminated area of the earth, wherein the contaminated area of the earth has a subsurface water table and a subsurface vadose zone above the water table, the contaminant being present in the vadose zone, which comprises the steps of:

establishing a borehole extending downwardly from the surface of the ground within the contaminated area, said borehole extending below the water table;

placing a first conduit within said borehole so that a ring-shaped zone is formed between the wall of said borehole and said first conduit, said first conduit having a perforate lower portion located in the vadose zone and spaced vertically above the water table so that fluids can flow from the vadose zone into the interior of said first conduit, said perforate lower portion having an upper end and a lower end, said first conduit having an imperforate upper portion above the upper end of said perforate lower portion,

placing a separate second conduit in said borehole and providing a pump to pump water through said second conduit,

filling fluid-permeable first fill material into a lower portion of said ring-shaped zone around said perforate lower portion of said first conduit and which extends to the upper end of said perforate lower portion so that said first fill material will permit fluid readily to flow into said perforate lower portion of said first conduit;

filling a second fill material of low fluid permeability into an upper portion of said ring-shaped zone around said imperforate upper portion of said first conduit, said second fill material being effective to impede flow of air from the surface of the ground to the lower portion of the borehole;

applying a vacuum to the upper end of said first conduit effective to induce flow of air and a gas containing vapor of said contaminant present in said vadose zone into the lower portion of said first conduit and thence to the upper end of said conduit, the vacuum being effective to cause vaporization of a substantial quantity of said contaminant within the vadose zone around the borehole so that said contaminant is removed from the ground in vapor form, whereby the same borehole can be used for monitoring and removing ground water and as a well for separately removing volatilized contaminant.