In-well air stripping and adsorption

• US 6,254,310 B1
• Filed: 05/08/2000
• Issued: 07/03/2001
• Est. Priority Date: 05/19/1997
• Status: Expired due to Fees

• Current Assignee: Arcadis Geraghty & Miller Inc. (Arcadis N.V.)
• Original Assignee: Arcadis Geraghty & Miller Inc. (Arcadis N.V.)
• Inventors: Suthersan, Suthan S.
• Primary Examiner(s): Will, Thomas B.
• Assistant Examiner(s): Pechhold, Alexandra K.
• Application Number:
  US09/566,508
• Time in Patent Office: 421 Days
• Field of Search: 405/128, 405/258, 405/129, 405/131, 210/747, 166/267, 166/266, 166/272, 166/273
• US Class Current: 210/747.7
• 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 from the phreatic zone, also known as the saturation zone, or groundwater. The technique preferably involves gas sparging while slowing down the sparging process by placing packing balls into an eductor tube. A preferred embodiment of the system is comprised of a means for supplying gas to the lower extent of a well which induces a flow of groundwater and gas bubbles up the well. The system may also contain 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 to the water table. The system may further comprise an eductor tube contained in the conduit which extends from the top extent of the conduit to the saturation zone. Packing balls may be located between the eductor tube and the means for supplying gas to the lower extent of the well. The system may also include separating the gas bubbles from the groundwater at the top of the conduit.

Claims

1. A method for gas sparging of contaminants from groundwater, said method comprising the steps of:

injecting a gas into the lower extent of a well, said injected gas producing gas bubbles in groundwater located therein and forcing a combination of said groundwater and said gas bubbles to simultaneously rise up said well, whereby VOCs in said groundwater are transferred to said rising gas bubbles inside said well;

placing material into said well, such that said groundwater and said gas bubbles are forced to pass over the surface of said material as said groundwater and said gas bubbles simultaneously travel up said well, thereby improving the transfer efficiency of said VOC'"'"'s to said gas bubbles; and

separating said gas bubbles from said groundwater.

2. The method of claim 1 further comprising:

supplying gas to the lower extent of said well by operating a pump in fluid communication with a tube positioned within a conduit extending within said well;

wherein said tube has an opening at its lower extent.

3. The method of claim 1 further comprising:

capturing said separated gas bubbles as a gas mixture; and

storing said gas mixture.

4. The method of claim 3 further comprising:

removing contaminants from said gas mixture; and

oxygenating said gas mixture.

5. The method of claim 4 further comprising returning said gas mixture which has been oxygenated to a supply of said gas.

6. The method of claim 1 wherein said gas is air.

7. The method of claim 1 wherein said gas is carbon monoxide.