Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF THE INVENTION:
Dual phase contaminated soil remediation apparatus
FIELD OF THE INVENTION
The present invention relates to a soil remediation apparatus for use in
treating soils
contaminated by hydrocarbons, which is capable to dealing with both liquid
phase and gas
phase contaminants.
BACKGROUND OF THE INVENTION
Whenever it is not practical to remove contaminated soil, the soil must be
treated in
situ. For successful soil remediation, one may require an apparatus capable of
treating liquid
phase contaminants, an apparatus capable of treating gas phase contaminants or
both types of
apparatus.
SUMMARY OF THE INVENTION
What is required is a dual phase contaminated soil remediation apparatus.
According to the present invention there is provided a dual phase contaminated
soil
remediation apparatus which includes means for connection with a well. A
groundwater
2 0 holding tank is provided having a groundwater feed inlet through which
contaminated
groundwater is fed into the holding tank from the well and a treated
groundwater outlet. The
level of groundwater in the holding tank fluctuates with the level of
groundwater in the well.
An air diffuser is positioned in a lower portion of the holding tank. An air
blower is provided
having a blower discharge conduit which places the air blower in fluid
communication with
2 5 the air diffuser. Air supplied by the air blower is discharged into the
air diffuser and bubbles
up though contaminated groundwater in the holding tank thereby providing an
air stripping
treatment to the contaminated groundwater. A first air supply conduit is
provided, which is
adapted to supply air from atmosphere to the air blower. A second air supply
conduit is
provided, which adapted to supply air from the well to the air blower. When
the second air
3 0 supply conduit is used a suction force is applied to the well to extract
hydrocarbon vapours
from surrounding soils into the well. A float activated valve is provided
which is adapted to
selectively switch between the first air supply conduit and the second air
supply conduit,
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depending upon the groundwater level in the holding tank. The use of the float
activated
valve enable vapour extraction to be performed whenever groundwater levels in
the well are
low, as determined by the relative level of groundwater in the holding tank.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the
following description in which reference is made to the appended drawings, the
drawings are
for the purpose of illustration only and are not intended to in any way limit
the scope of the
invention to the particular embodiment or embodiments shown, wherein:
FIGURE 1 is a side elevation view, in section, of a dual phase contaminated
soil
remediation apparatus constructed in accordance with the teachings of the
present invention.
FIGURE 2 is a side elevation view, in section, of a dual phase contaminated
soil
remediation apparatus illustrated in FIGURE 1, air stripping mode due to
relatively high
water levels.
FIGURE 3 is a side elevation view, in section, of a dual phase contaminated
soil
remediation apparatus illustrated in FIGURE 1, vapour extraction mode due to
relatively low
water levels.
FIGURE 4 is a side elevation view, in section, of a dual phase contaminated
soil
2 0 remediation apparatus illustrated in FIGURE 1, in an overflow mode.
FIGURE 5 is a side elevation view, in section, of a dual phase contaminated
soil
remediation apparatus illustrated in FIGURE 1, in a cleaning mode.
2 5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a dual phase contaminated soil remediation apparatus
generally identified by reference numeral 10, will now be described with
reference to
FIGURES 1 through 5.
3 0 Structure and Relationship of Parts:
Referring now to FIGURE 1, there is shown dual phase contaminated soil
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remediation apparatus 10. Apparatus 10 is connected to a well 12 by connection
14. There is
a ground water holding tank 16, which has a groundwater feed inlet 18 and a
treated
groundwater outlet 19. Water is pumped from well 12 to holding tank 16 through
groundwater feed inlet 18 by a pump 21, which is responsive to the level of
groundwater in
well 12. The flow of contaminated groundwater may be controlled by flow
control valve 17.
Contaminated groundwater is fed into holding tank 16 from well 12 through
groundwater
feed inlet 18. The level of groundwater in holding tank 16 fluctuates with the
level of
groundwater in well 12, but, as shown in FIGURES 2 to 4, the level only drops
to just
below treated groundwater outlet 19, and is prevented from rising above a
holding tank
overflow 36. Referring again to FIGURE l, an air diffuser 22 is positioned in
a lower
portion of holding tank 16. There is an air blower 24 and a blower discharge
conduit 26 that
places air blower 24 in fluid communication with air diffuser 22, as well as a
exhaust conduit
25 at the top of holding tank 16. Referring to FIGURE 2, in this arrangement,
air supplied by
air blower 24 is discharged into air diffuser 22 and bubbles up through
contaminated
groundwater 20 in holding tank 16 thereby providing an "air stripping"
treatment to
contaminated groundwater 20, which may also be referred to as "air sparging".
A first air
supply conduit 28 is adapted to supply air from atmosphere to air blower 24. A
second air
supply conduit 30 is adapted to supply air from well 12 to air blower 24, such
that a suction
force is applied to well 12 to extract hydrocarbon vapours from surrounding
soils 32 into well
2 0 12. A float activated valve generally indicated by 34 is adapted to
selectively switch between
first air supply conduit 28 and second air supply conduit 30 depending upon
the groundwater
levels in well 12, as determined by the relative level of groundwater in
holding tank 16. Float
activated valve 34 includes a float 46 within a housing 48, with float 46
connected by a rod 50
to an air control shuttle 52 within an air control assembly 54. As float 46
rises or falls, air
2 5 control shuttle rises or falls accordingly, such that air is diverted
through different conduits.
A holding tank overflow 36 is provided, which diverts excess groundwater 20
back to well
12. Overflow 36 includes a housing 37 with a float 39 within. As water enters
housing 37,
float 39 rises and unstops the overflow return line 41.
3 0 Referring now to FIGURE 5, a cleaning circuit 38, which is isolated by
valves 17, 39,
and 43 connects holding tank overflow 36 to groundwater feed inlet 18. A
circulation pump
44 permits cleaning solution 42 to be circulated through groundwater feed
inlet 18 into
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holding tank 16, out holding tank overflow 36 and then through cleaning
circuit 38 and back
through groundwater feed inlet 18 to holding tank 16. Cleaning solution is
introduced
through a container 40. Circulation pump 44 is placed within container 40,
such that cleaning
solution 42 is drawn from container 40 through circuit 38. It will be apparent
to those skilled
in the art that other methods of introducing cleaning solution are possible.
Operation:
The operation of dual phase contaminated soil remediation apparatus 10 will
now be
discussed with reference to FIGURES 1 to 5. Apparatus 10 is installed as shown
in
FIGURE 1. In FIGURES 2 to 4, the arrows represent the direction of air flow.
Refernng to
FIGURE 2, apparatus 10 is in an air stripping mode. Pump 21 is activated by
the level of
groundwater in well 12. As pump 21 pumps groundwater from well 12, holding
tank 16 and
housing 48 fills with groundwater 20. As groundwater rises in housing 48,
float 46 is forced
upward, which in turn forces air control shuttle 52 to a raised position, so
that air blower 24
draws air from atmosphere through first air supply conduit 28. The air is
transmitted through
air diffuser 22, such that the air bubbles up through contaminated groundwater
20 in holding
tank 16 thereby providing an air stripping treatment. The air is then
discharged through
2 0 exhaust conduit 25. Treated groundwater exits from holding tank 16 through
treated
groundwater outlet 19. Refernng now to FIGURE 3, there is illustrated a vapour
extraction
mode. As the level of groundwater in well 12 drops, pump 21 is deactivated and
the water in
housing 48 exits. As the level of water in housing 48 falls, float 46 and air
control shuttle 52
also fall. Once air control shuttle 52 is in a lowered position, air is drawn
by air blower 24
2 5 from well 12, which causes contaminated air to be drawn from surrounding
soils 32. Air is
circulated through air blower 24 and out first air supply conduit 28 which
acts as an exhaust
conduit in this situation. Referring now to FIGURE 4, apparatus 10 is in an
overflow mode.
If a problem occurs, such as treated groundwater outlet 19 becoming plugged,
excess
groundwater enters housing 39 causing float 37 in holding tank overflow 36 to
rise. Once
3 0 float 37 rises, excess groundwater is diverted through overflow diversion
line 41 back into
well 12. Refernng to FIGURE 5, apparatus 10 is in a cleaning mode. It is
preferable to
regularly clean apparatus 10 for preventative maintenance and to prolong the
working life.
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With previous devices, cleaning required partial disassembly. The present
invention enables
cleaning without such disassembly. Air blower 24 and pump 21 are not required
for this and
may be shut off. Valves 12, 39 and 43 are closed to isolate cleaning circuit
38. Circulation
pump 44 circulates cleaning solution 42 from container 40 along cleaning
circuit 38, into
5 groundwater feed inlet 18 of holding tank 16, out of holding tank 16 into
holding tank
overflow 36, then through cleaning circuit 38 back to container 40. This is
cycle through
cleaning circuit 38 is repeated numerous tunes to ensure that all deposits are
flushed from
holding tank 16 by cleaning solution 42.
In this patent document, the word "comprising" is used in its non-limiting
sense to
mean that items following the word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the
possibility that more than one of the element is present, unless the context
clearly requires that
there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made
to the
illustrated embodiment without departing from the spirit and scope of the
invention as
hereinafter defined in the Claims. For example, as is known in the art, water
from a well may
2 0 be pumped to a phase separation tank to remove floating contaminants, such
as oil. Water
may then be pumped from the bottom of this tank to the holding tank for
treatment, leaving
the contaminants floating in the tank. Also, filters may be required in some
jusrisdictions to
further clean the discharges. These, and other requirements, may be included
according to the
situation.
