Dual point adjustable depth air sparging well system

Abstract

An adjustable depth air sparging well system having a fixed depth air injection point and an adjustable depth air injection point for injecting compressed air into saturated or groundwater regions of the soil's subsurface to remove volatile contaminants from the soil's subsurface. A flow-through air sparge packer which is slidably mounted within the well casing of the air sparging well system allows a user to adjust the depth at which the adjustable depth air injection point is set.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a system for removing environmentally harmful volatile contaminants from saturated or groundwater regions of the soil subsurface. More particularly, the present invention relates to a dual point adjustable depth air sparging system which uses injected air to remove volatile contaminants from saturated or groundwater regions of the soil's subsurface.

2. Description of the Prior Art

Air sparging is a relatively recent and a very innovative technology that uses air injected under pressure to remove environmentally harmful volatile contaminants. Air sparging systems are capable of removing volatile contaminants such as gasoline, certain solvents and jet fuels from the groundwater region of the soil subsurface. In particular, air sparging systems are used to remove residual source contamination, clean up dissolved phase contamination, and contain a migrating contaminant plume.

U.S. Pat. No. 6,305,378 for an “Adjustable Depth Air Spargimg Well” discloses a flow through packer which is slidably mounted within a well casing allowing for vertical movement of the flow through packer within the well casing. The flow through packer includes an inflatable packer fabricated from inflatable elastomeric tubing, a lower end portion of an air supply tube which has a plurality of openings for providing pressurized air to inflate the packer, and a pair of elastomer/rubber packer end caps. An air compressor is coupled to the air supply tube supplying pressurized air to the inflatable packer which inflates the packer holding the packer at a fixed depth within the well casing. Deflating the inflatable packer allows for vertical movement of the inflatable packer within the well casing. Positioned at the lower end of the air supply tube is a check valve and screen pressure regulator through which air under pressure passes to a well screen. The well screen, which comprises the lower portion of the well casing, is mounted in the soil's saturated zone. The pressurized air next passes through the well screen into the soil's saturation zone removing volatile contaminants and transferring the contaminants to the soil's vadoze zone.

There is a need, however, for a second point of air injection, preferably at a fixed depth to provide additional air flow channels resulting in the removal of all volatile contaminants from the saturated or ground water regions of the soil subsurface being treated.

SUMMARY OF THE INVENTION

The dual point adjustable depth air sparging well system comprising the present invention provides for an adjustable point of air injection and a second stationary point of air injection to remove all volatile contaminants from the saturated or ground water regions of the soil subsurface being treated.

The dual point adjustable depth air sparging well system requires two sources of pressurized air to supply the air sparging well system for full functionality. A flexible air supply line supplies pressurized air to an adjustable depth flow-through packer which includes a check valve and screen pressure regulator through which the pressurized air under pressure passes to a well screen. This combination forms a first point of air injection. An annular air supply line supplies air to a second point of air injection, which is located at a fixed depth above an air sparge packer for the flow-through packer.

An air blower supplies pressurized air via the flow-through packer flexible air supply line and an annular air supply line to a well head air supply manifold positioned at the upper end of the well casing for dual point adjustable depth air sparging well. The manifold is pneumatically sealed using a compression fitting containing a rubber o-ring. The compression fitting prevents pressurized air from escaping into the atmosphere through the well head. In addition, the compression fitting seal serves the purpose of mechanically locking the flow-through packer in place at a pre-selected depth chosen by operator. This prevents vertical movement of the flow-through packer when the air sparging well system is operational.

The air traveling through the flow-through packer inflates the packer, sealing it against the well casing's internal wall and preventing the injected air from flowing back up the interior of the well casing.

A well screen, which comprises the lower portion of the well casing, is mounted in the soil's saturated zone. Pressurized air passes through the well screen into the soil's saturation zone removing volatile contaminants and transferring the contaminants to the soil's vadoze zone.

Air supplied to the well head manifold flows through the space between an air supply tube, which is connected to the flow-through packer, and an internal surface of the wall casing. The air exits the top portion of the well screen above the inflated flow-through packer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a dual point adjustable depth air sparging well system which has a well head manifold allowing for a sealed secondary stream of air to be injected through the upper portion of the well system;

FIG. 2 illustrates a typical air flow pattern generated by the well system of FIG. 1 to remove volatile contaminants from the saturated or groundwater regions of the soil subsurface;

FIG. 3 is a detailed view illustrating the flow through air sparge packer for the dual point adjustable depth air sparging well of FIG. 2; and

FIG. 4 illustrates another embodiment of the adjustable depth air sparging well system which provides for a third stream of air to be injected into the soil subsurface at a pre-selected depth.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, FIG. 2 illustrates a typical air flow pattern generated by the dual point adjustable depth air sparging well system 20 of FIG. 1 to remove volatile contaminants from the saturated or groundwater regions of the soil subsurface. The dual point adjustable depth air sparging well 20 is vertically positioned and passes through the vadoze zone 22 of the soil 24 into the saturated zone 26 of the soil 24. It should be noted that the saturated zone 26 of the soil 24 is homogeneous except for the confining soil lense. Boundary line or water table 28 indicates where in the soil the boundary between vadoze zone 22 and saturated zone 26 occurs.

An air blower 38 supplies pressurized air via a flexible air supply line 40 and an annular air supply line 42 to a well head air supply manifold 44 positioned at the upper end of the well casing 68 for dual point adjustable depth air sparging well 20. An air compressor may be used as air blower 38.

Well head sir supply manifold 44 has two air inlet ports 46 and 48 with air inlet port 46 being connected to flexible air supply line 40 and air inlet port 48 being connected to air inlet line 48. The packer air stream represented by arrow 50 is supplied to an air sparge flow-through packer 54 and a well screen 96. The annular air stream represented by arrow 51 is supplied to a stationary secondary air injection point 58. Blower 38 is capable of supplying pressurized air at flow rates of between 5 scfm and 40 scfm to air sparge flow-through packer 54 and screened well 96 which is that portion of a well casing 68 extending into the soil's saturated zone 26. Blower 38 is also capable of supplying pressurized air at flow rates of between 5 scfm and 40 scfm to secondary air injection point 58.

Located at the upper end of dual point adjustable depth air sparging well system 20 is a compression fitting seal and packer lock mechanism 62. Compression fitting seal and packer lock mechanism 62, which contains a rubber O-ring, secures the flexible air supply tube 40 to the air inlet port 46 of air sparging well system 20. The compression fitting prevents leakage of compressed air into the atmosphere through the well head. In addition, the compression fitting seal and packer lock mechanism 62 allows a user of air sparging well system 20 to mechanically lock the flow-through packer 54 in place at a pre-selected depth within the saturated zone 26, which is chosen by the user. This prevents vertical movement of the flow-through packer when the air sparging well system is operational.

Referring to FIGS. 2 and 3, flow-through air sparge packer 54 is slidably mounted or positioned within a well casing 68 allowing for vertical movement of flow-through air sparge packer 54 within well casing 68. As shown in FIG. 1 well casing 68 extends from the soil's surface 45 through the vadoze zone 22 into the saturated zone 26 from which volatile contaminants are to be removed.

Flow-through air sparge packer 54 comprises an inflatable packer fabricated from inflatable elastomeric tubing, a lower end portion 72 of air supply tube 52 which has a plurality of openings 74, and a pair of elastomeric packer end caps 76 and 78. Packer end cap 76 is secured to one end of lower end portion 72 by a first stainless steel strapping 80. Packer end cap 78 is also secured to the other end of lower end portion 72 by a second stainless steel strapping 82. Stainless steel straps 80 and 82 respectively seal end caps 76 and 78 to packer air supply tube 52 in the manner illustrated in FIG. 4.

When air under pressure passes through openings 74 (in the manner indicated by arrows 84) the outer surface 86 of inflatable packer 54 presses against the inner surface 88 of well casing 68 which holds adjustable depth flow-through air sparge packer 54 in a fixed position within well casing 68. When inflatable packer 54 is not under pressure, inflatable packer 54 deflates which allows for vertical movement of flow-through air sparge packer 54 within well casing 68. When inflatable packer 54 is inflated a seal is formed which prevents injected air from reentering the well casing 68 and subsequently short circuiting air flow through the contaminated regions of the soil's saturation zone 26.

At this time it should be noted that flow through packer air supply tube 52 has an outside diameter of approximately 0.5-1.0 inches, while well casing 68 has an inside diameter of approximately 1.0-2.5 inches.

Positioned at the lower end of flow through packer air supply tube 52 is a check valve and screened pressure regulator 92. The check valve and screened pressure regulator 92 has its pressure regulator screen fitted to the regulator's exit port to prevent sediment from entering the flow-through packer 54. Air under pressure passes the one valve 92 in the manner indicated by arrows 94. The pressurized air next passes through well screen 96 (also depicted by arrows 94) into the soil's saturated zone 26.

As the elastomeric tubing inflates, pressure within inflatable packer 54 will rise until pore and hydrostatic pressures associated with the injection depth of adjustable depth air sparging well 20 are overcome. Once these pressures are overcome, pressurized air flows out the check valve and screened pressure regulator 92 of inflatable packer 54 through well screen 96 into the contaminated aquifer or saturated zone 26. Air flow within saturated zone 26 is depicted in FIG. 1 as being through air channels 98. Pressurized air which passes through the well screen 96 into the soil's saturation zone 22 removes volatile contaminants from saturation zone 26 and transfers the contaminants to the soil's vadoze zone 22.

Pressurized air supplied to the well head manifold 44 flows from inlet port 48 through the space between the packer air supply tube 52, and an internal surface 102 of the well casing 68. The pressurized air exits the top portion of the well screen 96 above the inflated flow-through packer 54 in the manner depicted by arrows 106.

Referring to FIG. 1, illustrates an air flow pattern of sparged air as it exits both the stationary injection point 58 and adjustable injection points 56. The stationary injection point 58 is typically positioned at a shallow depth (as shown in FIG. 1) to allow the user to place the adjustable depth flow-through packer 54 at a greater range of injection depths. Injecting compressed air in the soil at a shallow depth results in the generation of air flow channels 108, which have the advantage of stripping a significant portion of volatile Nonaqueous phase contaminants from the saturated region 26 that tend to reside at or just below the water table. Applying two points of injection 56 and 58 through a single air sparging well system 20 significantly improves the overall cleanup process and the speed at which it occurs.

Referring to FIG. 4, the air sparging well system 20 can be modified to include additional stationary points for air injection. FIG. 4 illustrates a well system 120 that has been modified to have three points of air injection 122, 124 and 126. Air injection points, which are represented by arrows 122 and 124 are fixed points of air injection and air injection point 126 is an adjustable point of air injection which is selected by the user by adjusting the depth at which air sparge flow through packer 128 is positioned.

A second air supply manifold 130 having a compression fitting seal is also required for adjustable depth air sparging well system 120. The air supply manifold 130 is positioned near the upper end of the well casing 140 for well system 120 directly underneath the well head air supply manifold 142 which is positioned at the upper end of the well casing 140. Air supply manifold 130 has an air inlet port 132 which receives an outer annular pressurized air stream (indicated by arrow 134) from an external source such as the blower 38 illustrated in FIG. 1. The pressurized air passes from air inlet port 132 through the space between the outer surface of well casing 140, and an internal surface of a manifold wall 146 which extends vertically downward from manifold 130. The pressurized air exits the well system 120 at a second fixed injection point in the manner indicated by arrows 122 to remove soil contaminants from the ground.

In a similar manner, pressurized air (represented by arrow 138) supplied to air inlet port 136 of manifold 142 exits the well system 120 a second fixed injection point in the manner indicated by arrows 124 to remove soil contaminants from the ground. System 120 also has an adjustable injection point (represented by arrows 126) below packer 128 through which pressurized passes into the ground to remove soil contaminants from the ground. The packer air stream (represented by air 139) for the adjustable injection point is supplied to manifold 142 by a blower of the type illustrated in FIG. 1.

Additional injection points may be added with each point requiring its own air supply manifold and annular wall section.

From the foregoing, it is readily apparent that the present invention comprises a new, unique, and exceedingly useful dual point adjustable depth air sparging well for removing volatile contaminants from saturated and groundwater regions of the soil which constitutes a considerable improvement over commercially available air sparging system which do not allow for depth adjustment of the system.

Claims

1. An adjustable depth air sparging system for removing volatile contaminants from a saturated zone within the soil subsurface comprising:

(a) a vertically oriented well casing extending downward into the saturated zone within the soil subsurface, said well casing having a screened portion at a lower end thereof positioned within said saturated zone;

(b) an air supply tube movably disposed within said well casing, said air supply tube having a plurality of openings positioned at a lower end thereof;

(c) air supply means for providing pressurized air to said air supply tube;

(d) a flow-through air sparge packer affixed to the lower end of said air supply tube, said flow-through air sparge packer covering the openings within said air supply tube forming an air tight seal around the lower portion of said air supply tube;

(e) adjustable depth injecting means affixed to the lower end of said air supply tube to receive said pressurized air, said adjustable depth injecting means injecting said pressurized air through the screened portion of said well casing below said air sparge packer into said saturated zone at a plurality of pre-selected depths, forming air channels at each of said pre-selected depths through which said pressurized air flows to remove said volatile contaminants from said saturated zone;

(f) locking means for locking said adjustable depth injecting means in a fixed position at each of said pre-selected depths to prevent vertical movement of said adjustable depth injecting means when said air sparging system is operational; and

(g) fixed depth injecting means located within the screened portion of said well casing above said air sparge packer, said fixed depth injecting means receiving said pressurized air from said air supply means and then injecting said pressurized air through the screened portion of said well casing above said air sparge packer into said saturated zone forming additional air channels through which said pressurized air flows to remove said volatile contaminants from said saturated zone.

2. The adjustable depth air sparging system of claim 1 wherein a user of said air sparging system selects each of said pre-selected depths at which said adjustable depth injecting means is positioned within said saturation zone prior to activating said air sparging system.

3. The adjustable depth air sparging system of claim 1 wherein said air supply means comprises an air blower.

4. The adjustable depth air sparging of claim 1 wherein said adjustable depth injecting means comprises a check valve and screened pressure regulator through which said pressurized air passes to the screened portion of said well casing.

5. The adjustable depth air sparging system of claim 1 wherein said flow-through air sparge packer is inflatable, said flow-through air sparge packer when inflated by said pressurized air passing through said plurality of openings holding said adjustable depth injecting means in said fixed position at each of said plurality of pre-selected depths to prevent the vertical movement of said adjustable depth injecting means when said air sparging system is operational.

6. The adjustable depth air sparging system of claim 5 wherein said flow-through air sparge packer is fabricated from inflatable rubber or elastomeric tubing.

7. The adjustable depth air sparging system of claim 6 wherein said flow-through air sparge packer includes:

(a) first and second end caps, said first end cap being located at an upper end of said air sparge packer and said second end cap being located at a lower end of said air sparge packer, said first and second end caps being adapted to secure said air sparge packer to the lower end of said air supply tube, wherein said first and second end caps are fabricated from rubber or an elastomer;

(b) a first stainless steel strapping mounted on said first end cap, said first stainless steel strapping when tightened securing said first end cap to said air supply tube; and

(c) a second stainless steel strapping mounted on said second end cap, said second stainless steel strapping when tightened securing said second end cap to said air supply tube.

8. An adjustable depth air sparging system for removing volatile contaminants from a saturated zone within the soil subsurface comprising:

(a) a vertically oriented well casing extending downward into the saturated zone within the soil subsurface, said well casing having a screened portion at a lower end thereof which is positioned within said saturated zone;

(b) an air supply tube movably disposed within said well casing, said air supply tube having a plurality of openings positioned at a lower end thereof;

(c) air supply means for providing pressurized air to said air supply tube;

(d) a flow-through air sparge packer affixed to the lower end of said air supply tube, said flow-through air sparge packer covering the openings within said air supply tube forming an air tight seal around the lower portion of said air supply tube;

(e) adjustable depth injecting means affixed to the lower end of said air supply tube to receive said pressurized air, said adjustable depth injecting means injecting said pressurized air through the screened portion of said well casing below said air sparge packer into said saturated zone at a plurality of pre-selected depths, forming air channels at each of said pre-selected depths through which said pressurized air flows to remove said volatile contaminants from said saturated zone;

(f) locking means for locking said adjustable depth injecting means in a fixed position at each of said pre-selected depths to prevent vertical movement of said adjustable depth injecting means when said air sparging system is operational; and

(g) first and second fixed depth injecting means located within the screened portion of said well casing above said air sparge packer, said first and second fixed depth injecting means receiving said pressurized air from said air supply means and then injecting said pressurized air through the screened portion of said well casing above said air sparge packer into said saturated zone, each of said first and second fixed depth injecting means injecting said pressurized into said saturation zone forming additional air channels through which said pressurized air flows to remove said volatile contaminants from said saturated zone.

9. The adjustable depth air sparging system of claim 8 wherein a user of said air sparging system select's each of said pre-selected depths at which said adjustable depth injecting means is positioned within said saturation zone prior to activating said air sparging system.

10. The adjustable depth air sparging system of claim 8 wherein said air supply means comprises an air blower.

11. The adjustable depth air sparging of claim 8 wherein said adjustable depth injecting means comprises a check valve and screened pressure regulator through which said pressurized air passes to the screened portion of said well casing.

12. The adjustable depth air sparging system of claim 8 wherein said flow-through air sparge packer is inflatable, said flow-through air sparge packer when inflated by said pressurized air passing through said plurality of openings holding said adjustable depth injecting means in said fixed position at each of said plurality of pre-selected depths to prevent the vertical movement of said adjustable depth injecting means when said air sparging system is operational.

13. The adjustable depth air sparging system of claim 12 wherein said flow-through air sparge packer is fabricated from inflatable rubber or elastomeric tubing.

14. The adjustable depth air sparging system of claim 13 wherein said flow-through air sparge packer includes:

(a) first and second end caps, said first end cap being located at an upper end of said air sparge packer and said second end cap being located at a lower end of said air sparge packer, said first and second end caps being adapted to secure said air sparge packer to the lower end of said air supply tube, wherein said first and second end caps are fabricated from rubber or an elastomer;

(b) a first stainless steel strapping mounted on said first end cap, said first stainless steel strapping when tightened securing said first end cap to said air supply tube; and

(c) a second stainless steel strapping mounted on said second end cap, said second stainless steel strapping when tightened securing said second end cap to said air supply tube.

15. An adjustable depth air sparging system for removing volatile contaminants from a saturated zone within the soil subsurface comprising:

(a) a vertically oriented well casing extending downward into the saturated zone within the soil subsurface, said well casing having a screened portion at a lower end thereof which is positioned within said saturated zone;

(b) an air supply tube movably disposed within said well casing, said air supply tube having a plurality of openings positioned at a lower end thereof;

(c) an air compressor for providing pressurized air to said air supply tube;

(d) a flow-through air sparge packer affixed to the lower end of said air supply tube, said flow-through air sparge packer covering the openings within said air supply tube forming an air tight seal around the lower portion of said air supply tube;

(e) a flexible air supply line having one connected to said air compressor and an opposite end connected to said air supply tube, said flexible air supply line forming a passageway for supplying said compressed air from said compressor to said air supply tube

(e) a check valve and screened pressure regulator affixed to the lower end of said air supply tube to receive said pressurized air, said check valve and screened pressure regulator injecting said pressurized air through the screened portion of said well casing below said air sparge packer into said saturated zone at a plurality of pre-selected depths, forming air channels at each of said pre-selected depths through which said pressurized air flows to remove said volatile contaminants from said saturated zone, wherein a user of said air sparging system selects each of said pre-selected depths at which said check valve and screened pressure regulator is positioned within said saturation zone prior to activating said air sparging system;

(f) a packer locking mechanism located at an upper end of said well casing for locking said check valve and screened pressure regulator in a fixed position at each of said pre-selected depths to prevent vertical movement of said check valve and screened pressure regulator when said air sparging system is operational; and

(g) a fixed depth air injecting device located within the screened portion of said well casing above said air sparge packer, said fixed depth air injecting device being connected to said air compressor to receive said pressurized air from said air compressor and then inject said pressurized air through the screened portion of said well casing above said air sparge packer into said saturated zone, said fixed depth air injecting device injecting said pressurized into said saturation zone forming additional air channels through which said pressurized air flows to remove said volatile contaminants from said saturated zone.

16. The adjustable depth air sparging system of claim 15 further comprising a second fixed depth air injecting device positioned within the screened portion of said well casing above said air sparge packer, said second fixed depth air injecting device being connected to said air compressor to receive said pressurized air from said air compressor and then inject said pressurized air through the screened portion of said well casing above said air sparge packer into said saturated zone, said second fixed depth air injecting device injecting said pressurized into said saturation zone forming additional air channels through which said pressurized air flows to remove said volatile contaminants from said saturated zone.

17. The adjustable depth air sparging system of claim 16 wherein said second fixed depth air injecting device comprises an air supply manifold.

18. The adjustable depth air sparging system of claim 15 wherein said flow-through air sparge packer is inflatable, said flow-through air sparge packer when inflated by said pressurized air passing through said plurality of openings holding said adjustable depth injecting means in said fixed position at each of said plurality of pre-selected depths to prevent the vertical movement of said adjustable depth injecting means when said air sparging system is operational.

19. The adjustable depth air sparging system of claim 18 wherein said flow-through air sparge packer is fabricated from inflatable rubber or elastomeric tubing.

20. The adjustable depth air sparging system of claim 19 wherein said flow-through air sparge packer includes:

(a) first and second end caps, said first end cap being located at an upper end of said air sparge packer and said second end cap being located at a lower end of said air sparge packer, said first and second end caps being adapted to secure said air sparge packer to the lower end of said air supply tube, wherein said first and second end caps are fabricated from rubber or an elastomer;

(b) a first stainless steel strapping mounted on said first end cap, said first stainless steel strapping when tightened securing said first end cap to said air supply tube; and

(c) a second stainless steel strapping mounted on said second rubber end cap, said second stainless steel strapping when tightened securing said second end cap to said air supply tube.