Hydraulic and earth engineering – Soil remediation – In situ contaminant removal or stabilization
Reexamination Certificate
2000-04-03
2001-10-23
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Soil remediation
In situ contaminant removal or stabilization
C405S128150, C405S128450, C166S387000, C166S311000, C166S188000, C166S242200, C210S170050
Reexamination Certificate
active
06305878
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a system for removing environmentally harmful volatile containments from saturated or groundwater regions of the soil subsurface. More particularly, the present invention relates to an adjustable depth air sparging well which uses injected air to remove volatile containments from the saturated or groundwater regions of the soil 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.
Referring to
FIG. 1
, the major components of an air sparging system, designated generally by the reference numeral
18
, (as shown in
FIG. 1
) consist of a permanently installed, vertical, single depth air sparge well
20
, an air blower or compressor
22
which supplies air under pressure to sparge well
20
and monitoring sensors and equipment (not illustrated in FIG.
1
). A screened bottom portion
24
of the air sparging system
20
is located below the contamination level
27
. Air under pressure is injected through the screened bottom portion
24
of system
20
into the soil's saturated zone
28
. This injected air strips the contaminants from a liquid phase to a vapor phase, and then transports the contaminants via air channels
30
to the soil's vadoze zone
32
for removal from the vadoze zone
32
.
Referring to
FIG. 2
, clay soils and highly stratified layers, represented generally by the reference numeral
34
, limit the effectiveness of air sparging systems
18
of the type illustrated in
FIG. 1
by significantly decreasing uniform air distribution throughout soil's saturated zone
28
. As shown in
FIG. 2
, the air channels
36
are not uniformly distributed throughout the soil's saturated zone
28
, resulting in areas of the saturated zone
28
from which volatile contaminants can not be removed. In particular, injected air will not penetrate the clay soils and highly stratified layers
34
, which leaves the volatile contaminants in the region
29
above the clay soils and highly stratified layers
34
in the saturated zone.
Nested air sparge wells have been used as an alternative to vertical sparge wells to remove volatile contaminants when the soil is highly stratified. Nested air sparge wells are costly due to the drilling cost associated with these wells.
A second alternative is to place vertical sparge wells adjacent to one another for uniform injection of air within the soil which will generally result in significant cost increases, while not assuring complete success at stratified sites within a contaminated saturated zone.
In addition, once nested or adjacent air sparge wells are installed, there is currently no method to adjust the sparging depth to assure that volatile contaminates are completely removed from contaminated saturated zones of the type illustrated in FIG.
2
.
Accordingly, there is a need for an adjustable depth air sparge well which will allow for the removal of environmentally harmful volatile contaminants from saturated or groundwater regions of the soil, especially where stratification is a significant problem. In addition, there is a need to provide an adjustable depth air sparge well which is relatively simple in design and provides for significant operational cost reduction over air sparging systems currently in use.
SUMMARY OF THE INVENTION
The present invention overcomes some of the disadvantages of the prior art including those mentioned above in that it comprises a relatively simple design yet highly efficient and effective system which uses injected air for the removal of environmentally harmful volatile containments from the saturated or groundwater regions of the soil.
The adjustable depth air sparging well system comprises 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 vitron 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 vitron rubber packer end caps. An air compressor is coupled to the air supply tube supplying pressurized air to inflate the packer. Deflating the inflatable packer allows for verticle movement of the inflatable packer within the well casing.
Positioned at the lower end of the air supply tube is a one way valve through which air under pressure passes to a well screen. The well screen comprises the lower portion of the well casing that is in contact with 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.
REFERENCES:
patent: 5348420 (1994-09-01), Bernhardt
patent: 5389267 (1995-02-01), Gorelick et al.
patent: 5577558 (1996-11-01), Abdul et al.
patent: 5855775 (1999-01-01), Kerfoot
patent: 5879108 (1999-03-01), Haddad
patent: 6109358 (2000-08-01), McPhee et al.
patent: 6174107 (2001-01-01), Martinell
patent: 6174108 (2001-01-01), Suthersan
Bagnell David
Kalmbaugh David
Lagman Frederick L.
The United States of America as represented by the Secretary of
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