In-well air stripping, oxidation, and adsorption

• US 6,007,274 A
• Filed: 05/19/1997
• Issued: 12/28/1999
• Est. Priority Date: 05/19/1997
• Status: Expired due to Fees

• Current Assignee: Piedmont Olsen Hensley, Inc. (Arcadis N.V.)
• Original Assignee: Arcadis Geraghty & Miller Inc. (Arcadis N.V.)
• Inventors: Suthersan, Suthan S.
• Primary Examiner(s): SUCHFIELD, GEORGE A
• Application Number:
  US08/858,267
• Time in Patent Office: 953 Days
• Field of Search: 166/267, 166/278, 166/310, 166/369, 166/370, 166/372, 166/75.12, 166/265, 210/170, 210/747, 210/758, 210/760, 210/908, 210/912, 405/52, 405/128
• US Class Current: 210/747.8
• CPC Class Codes: B09C 1/002 involving in-situ ground water treatment
• CPC Class Codes: B09C 1/005 Extraction of vapours or gases using vacuum or venting
• CPC Class Codes: B09C 1/08 chemically
• CPC Class Codes: B09C 2101/00 In situ

Abstract

A method and system for removing contaminants for the phreatic zone, also known as the saturation zone, or groundwater. The technique involves gas sparging and oxidation while increasing the surface area for mass transfer by the placing of packing balls into the eductor tube. The system is comprised of a means for supplying gas/ozone mixture to the lower extent of a well which induces a flow of groundwater and gas bubbles up the well. The system contains a conduit within the well, which extends below the water table. The conduit has a lower fluid-permeable section which is located below the water table and an upper fluid-permeable section which is adjacent the water table.

Claims

1. A method for removing contaminants from groundwater, comprising the steps of:

providing a well to extend below the water table into the phreatic zone;

injecting a gas/ozone mixture into the lower extent of said well to force groundwater up said well causing VOCs to be transferred to rising gas bubbles in addition to oxidation occurring inside said well;

providing packing materials with the flow of said groundwater and said gas bubbles up said well for enhancing the surface area for improved mass transfer efficiencies, into said well; and

optionally, separating said gas bubbles from the groundwater with vacuum vapor extraction, at the upper extent of said well.

2. The method of claim 1, further comprising:

supplying air/ozone mixture to the lower extent of said well by operating an air pump and ozone generator in fluid communication with a tube positioned within said conduit, wherein said tube has an opening at its lower extent.

3. The method of claim 1, further comprising:

capturing said separated gas bubbles; and

treating or discharging said captured air.

4. The method of claim 3, further comprising:

removing contaminants from said captured air; and

treating said captured air.

5. The method of claim 4, further comprising:

providing a trench or annular holes below the ground surface and filling said trench or annular holes with an adsorption media through which the air stripped water must pass.

6. The method of claim 1, further comprising separating said gas bubbles from the groundwater with vacuum vapor extraction, at the upper extent of said well.

7. A System for gas sparging of contaminants from groundwater, which comprises:

means for supplying gas/ozone mixture to the lower extent of a well to induce a flow of groundwater and gas bubbles up said well;

a conduit within said well, extending below the water table, said conduit having a lower fluid-permeable section below said water table and an upper fluid-permeable section adjacent said water table;

an internal pipe or eductor tube contained in said conduit which extends from the top extent of the conduit to the saturation zone;

packing balls located between said eductor tube and said means for supplying gas to the lower extent of said well; and

a means, located at the top of said conduit, for separating the gas bubbles from the groundwater VOC vapor contained in said gas bubbles.

8. The system of claim 7 wherein said packing balls are made of plastic media.

9. The system of claim 7, wherein said gas supplying means includes:

a tube within said conduit and eductor tube, wherein said tube extends from above said ground surface to below said water table, said tube having an opening at its lower extent; and

an air pump and an ozone generator in fluid communication with said tube.

10. The system of claim 7, further comprising a trench or annular holes near the top of said well, said trench or annular holes filled with adsorption media to further remediate said groundwater.

11. A method for removing contaminants from groundwater, comprising:

providing a well extending from the ground surface into the saturated zone;

providing a trench or hole below the ground surface;

injecting a gas into a lower extent of the well to induce a flow of groundwater and gas bubbles up the well;

providing packing material in the well so that the groundwater and gas bubbles flow over a surface of the packing material causing volatile organic compounds (VOCs) to be transferred to rising gas bubbles;

optionally separating the gas bubbles from the groundwater; and

placing adsorption media in the trench or hole for further treating the groundwater and gas bubbles.

12. A method for removing contaminants from groundwater comprising:

providing a well extending from the ground surface into the saturated zone;

injecting a gas comprising ozone into a lower extent of the well to induce a flow of groundwater and gas bubbles up the well;

providing packing material in the well so that the groundwater and gas bubbles flow over a surface of the packing material causing volatile organic compounds (VOCs) to be transferred to rising gas bubbles; and

optionally separating the gas bubbles from the groundwater.

13. A system for gas sparging of contaminants from groundwater comprising:

a well extending from the ground surface into the saturated zone;

a conduit within the well, extending below the water table, the conduit having a lower fluid-permeable section below the water table and an upper fluid-permeable section adjacent the water table;

packing material within the conduit; and

a gas supply in fluid communication with a lower extent of the well to induce a flow of groundwater and gas bubbles up said well.

14. The system of claim 13 further comprising an internal pipe within the conduit extending into the saturated zone and wherein the packing material is within the internal pipe.

15. The system of claim 13 further comprising a separator to separate the groundwater from the gas bubbles.

16. The system of claim 13 wherein the gas supply in fluid communication with the lower extent of the well comprises a tube within the conduit extending from the ground surface to below the water table.

17. The system of claim 16 wherein the gas supply in fluid communication with the lower extent of the well further comprises an ozone generator.

18. The system of claim 13 further comprising a trench or hole near the top of the well, the trench or hole filled with adsorption media for further treating the groundwater.

19. The system of claim 13 wherein the packing material is packing balls.