Method and apparatus for detection of volatile soil contaminants in situ

The invention relates to methods and apparatus for agitating and heating a sub-surface volume of soil to liberate volatile compositions therefrom which are transmitted through a special flow passage created through the soil to the soil surface where they are analysed to determine the presence or absence of selected contaminants. A low pressure sink is provided to ensure proper flow of volatiles rapidly to the surface and to prevent contamination of adjacent soil blocks or cylinders during treatment.

CROSS REFERENCES TO RELATED APPLICATIONS 
My co-pending U.S. applications Ser. No. 865,745, filed Aug. 26, 1985 now 
U.S. Pat. No. 4,776,409, for In Situ Waste Impoundment Treating Apparatus 
and Method of Using Same and Ser. No. 049,861 each disclose apparatus 
which physically agitates a subsurface volume of soil in situ, and 
preferably injects a heated fluid such as steam into the agitating soil 
which then releases volatile components which percolate upwardly through 
the soil to the ground surface where they can be analysed. Treatment 
methods and chemicals are then selected depending on the composition of 
the volatile components liberated from the sub-surface soil. 
My co-pending U.S. patent application Ser. No. 093,305 filed Sept. 3, 1987 
for a Device for Sampling Soils and Retaining Volatiles Therein and Method 
of Using Same discloses a soil sampling device which is inserted into the 
ground for taking an undisturbed soil sample and removing it from its 
subterranean location without loss of volatile components from the soil 
sample. 
BACKGROUND OF THE INVENTION AND PRIOR ART 
Although the inventions disclosed in my prior pending applications 
mentioned above perform perfectly well for their intended purposes, the 
apparatus shown in Ser. Nos. 865,745 and 049,861 is designed not only for 
the purpose of analysing the composition of soil contaminants but also for 
treating the soil, if necessary. In general, this results in apparatus 
which is larger and slower than need be for preliminary site testing where 
it is desirable to provide analytical results in real time. 
The inventions disclosed in Ser. No. 093,305 are intended for site analysis 
by gathering physically undisturbed samples of soil rather than for making 
a real time analysis of the contaminant content by liberating volatiles 
from the soil which are then analysed at the surface. 
Accordingly, it is an object of the present invention to provide an 
improved method and apparatus for liberating volatile gases from 
sub-surface soil locations which more quickly conducts the volatiles to 
the surface to enable analysis of such gases to determine the soil 
contents in real time. An additional object of the invention is to provide 
improved treatment methods and apparatus designed to ensure that no 
contamination of adjacent soil blocks takes place during treatment of the 
currently treated block or blocks. 
SUMMARY OF THE INVENTION 
The present invention accordingly provides a method of analysing soil to 
determine contaminants therein wherein a block or cylinder of soil is 
agitated and heated to release volatile contaminants which are then 
conducted through a relatively unobstructed flow path created in the soil 
to the surface where they may be analysed. Two different embodiments of 
apparatus for performing the method are disclosed.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a vertically extending main frame 10 comprised of four corner 
members 12, 14 extending vertically between an upper platform 16 and a 
lower platform 18. The corner members 12, 14 are connected together by a 
plurality of cross pieces 20 and diagonal reinforcing members 22 to 
provide structural rigidity. 
The main frame 10 is connected to a mobile tractor rig 24 by a plurality of 
struts 26 which are pivotally connected at one end to a lifting frame 37 
and at the other end to the tractor rig 24 as shown. A counterweight 28 
and hydraulic piston unit 30 on the tractor rig 24 permit lateral 
positioning of the main frame 10 relative to the tractor as desired. A 
vertical lifting piston/cylinder unit 35 connected at one end to the main 
frame 10 and at the other end to the lifting frame 35 is used to raise and 
lower the apparatus during movement from one location to the next. 
Mounted within the frame 10 is a vertically extending stem or rotatable 
Kelly 40 driven for rotary movement by a motor 46 shown on the lower 
platform 18. A geared connection between the motor 46 and a rotary drive 
table 48 which surrounds the Kelly 40 imparts rotary movement thereto. A 
motor load monitor is also provided for the purpose of obtaining motor 
load data which is representative of the plasticity of the soil being 
worked. The plasticity data is then used by the operator to adjust the 
speed of rotation of the Kelly 40 as necessary. Guide rollers 60 mounted 
on the table 48 engage vertically extending splines 50 on the Kelly 40 to 
guide vertical movement thereof. The mounting and the drive arrangement 
for the Kelly 40 are shown herein schematically as the detailed 
construction is well known in the prior art as, for example, in my prior 
application Ser. No. 049,861 mentioned above. 
A rigid gas containment shroud 58 is affixed to the underside of lower 
platform 18 at the lower end of the frame 10 and is positioned such that 
its lower edge 59 sealingly engages the earth surface S during operation 
of the device so as to prevent gases escaping from the block or cylinder 
of soil being worked from contaminating the ambient atmosphere. A rotary 
cutter 64 having a pair of oppositely disposed horizontally extending 
cutter blades 65 is affixed to the lower end of the Kelly 40. Powered 
drive means including a motor 70 and chain 72 trained over pulleys 74 is 
provided for vertical movement of the Kelly 40 and attached cutter 64 as 
is well known in the art. 
Turning now to FIG. 2, a schematic view of a first and presently preferred 
embodiment of the invention is shown in which a vertically extending 
hollow Kelly 40 is provided with at least one longitudinally extending 
spline 50 or annulus cutter welded to the exterior thereof. The spline or 
splines 50 preferably continuously extends along the vertical length of 
the Kelly 40 from the elevation of the cutter 64 at the bottom upwardly to 
the soil surface S and thence through a rotary gas seal 80 in the shroud 
58, then through the lower platform 18 and Kelly drive table 48 and 
finally upwardly to a swivel 90 attached to the upper end of the Kelly 40 
for vertical movement therewith for a purpose to be described. The spline 
50, during rotation of the Kelly 40, continuously cuts and keeps open, an 
annular passageway 56 which extends vertically from a first elevation E1 
at the cutter blades 65 upwardly to a second elevation E2 from which gas 
is withdrawn from the annulus 56. Preferably gas is withdrawn from the 
annulus 56 at the elevation of the shroud 58; however, it is possible to 
withdraw the gas from a different elevation than the elevation of the 
shroud. 
The swivel 90 is for the purpose of introducing pressurized fluid which may 
comprise steam or hot air from sources 97, 98 thereof into the rotating 
Kelly 40 through which it can be conducted downwardly for discharge at the 
cutter 64. A pressure intensifier pump 99 is provided as shown. The swivel 
90 has a non-rotatable upper portion 94 and a lower rotatable portion 96 
affixed to the Kelly 40 for rotation therewith. Both portions of the 
swivel 90 move vertically with the Kelly 40 as it is raised and lowered 
into operative positions for cutting at different elevations. The source 
of high pressure fluid connected by a flexible hose 102 to the upper 
swivel portion 94 in fluid communication with the interior of the hollow 
Kelly 40 or, alternatively, into a separate conduit (not shown) which may 
be provided in the Kelly 40. Typically, a separate conduit inside the 
Kelly will be chosen if it is desired to eject steam from the cutter 64 
into the soil whereas if only hot air is to be ejected, the interior of 
the Kelly 40 can be used as the air flow passageway and a separate conduit 
is not needed. 
FIGS. 3 A and 3 B show alternative cross sectional configurations of the 
Kelly 40. In either instance at least one longitudinally extending radial 
protrusion or spline 50 is needed to cut the annulus 56 during rotation of 
the Kelly 40. 
A pilot bit 66 may be affixed to the lower end of the Kelly 40. Cutter 
blades 65 as best seen in FIGS. 5 and 6 are affixed to the lower end of 
the hollow Kelly 40 and the Kelly interior (or the conduit therein if 
present) is placed into fluid communication with fluid passageways 106, 
108 in the cutter blades 65 and fluid discharge jets 100 in fluid 
communication with the passageways 106, 108. 
High pressure fluid from the sources 97, 98 is jetted outwardly from a 
plurality of jets 100 provided in the cutter 64 for this purpose. The 
heated fluid volatilizes many of the contaminant components typically 
found in waste disposal sites and causes them to migrate upwardly to the 
ground surface where they are collected in the shroud 58. 
A vertical travel monitor 110 is provided on the lower platform 18 for the 
purpose of accurately recording the vertical position of the Kelly 40 and, 
hence the first elevation or depth of the cutter 64 below a reference 
datum plane. This position data is then sent to a central processing unit 
for correlation with data provided by a gas analyser 120 which receives 
gas from the shroud 58 via a conduit 122 and a blower 124 for determining 
the composition of the gas collected in the shroud 58. The gas analyser 
typically comprises one or more of a flame ionization detector (FID), a 
gas chromatograph, a radiation detector, reactivity and conductivity 
analysers, a biological analyser, pH and oxidation reduction potential 
(ORP) meters, temperature and moisture meters and other components well 
known in the art. As described below, depth data can be correlated with 
gas contaminant composition and concentration data with sufficient 
precision to provide an accurate profile of the soil contaminants, their 
concentration and the depth at which the contaminants were encountered. 
Two or three dimensional maps of the contaminated ground area can then be 
made to display the correlated data. A monitor 126 for visual observance 
and a strip chart recorder 128 which provides a paper printout of the data 
in real time are provided so that the operator may then, if desired, 
repeat the process for verification. The blower 124 maintains a 
sufficiently negative pressure in the shroud 58 so that gases therein are 
not transmitted to atmosphere before passing through a gas scrubber 130 
which removes harmful contaminants therefrom. 
A vertical cross section of the gas seal 80 in the shroud 58 is shown in 
FIG. 4 to comprise an inner, rotatable section 82 affixed to the Kelly 40 
for rotation therewith and a stationary outer section 84 mounted in the 
top wall of the shroud 58. Bearings 86 mounted in a packed multi-part race 
88 provide minimum friction between the relatively rotating parts 82, 84. 
The cutter assembly is affixed to the lower end of the Kelly 40 and may be 
provided with a pilot bit 66 as shown. 
FIGS. 5, 6 and 7 show a presently preferred radial blade cutter design and 
the manner in which the cutter blades 65 create a zone of influence, i.e. 
a zone in which volatilization of contaminants takes place due to the 
combined action of agitation of the soil by the cutter blades 65 and the 
heating thereof by the high pressure fluid injection. Momentary heating of 
the soil in the zone of influence is coupled with physical agitation and 
homogenization of the soil near the cutters resulting in volatilization of 
contaminants in the soil. The cutter blades 65, together with the annulus 
cutter 50, open a substantially unobstructed flow path to rapidly conduct 
gases directly from the cutters to the shroud 58 where they can be 
analysed and correlated with the depth from which they originated. The 
blower 124 keeps the shroud 58 under a negative pressure, preferably minus 
about 4 inches of water, which creates a low pressure sink to which the 
volatile contaminants are directed. The cutter blade 65 has a generally 
planar horizontal portion 65a which extends radially from the Kelly 40 and 
which is provided with preferably two separate internal passageways 
106,108 for conducting air and/or steam therethrough. It will be 
appreciated that a single passageway can be provided instead of two 
separate passageways but that certain contaminant conditions encountered 
may make the use of air preferable to the use of steam (as for example 
when the ground water table is high or the soil is saturated) or vice 
versa. Thus, increased flexibility is afforded when separate passageways 
for air and steam are provided. As shown, the leading edge 65b of the 
cutter is provided with a plurality of spaced, downwardly inclined teeth 
65c for cutting into the soil. Intermediate the leading and trailing edges 
65b, 65d of the cutter an upstanding shield 67 is provided to protect the 
upwardly extending air and steam jets 100a, 100b during the cutting 
operation. The steam jets 100b are provided in a row behind the shield 67 
and the air jets 100a are provided in a row behind the steam jets 100b. 
This positioning of the air jets behind the steam jets asssists in keeping 
an open flow path from the cutters to the annulus 56 when both steam and 
air are used. The jets 100 may, if desired be angled toward the Kelly 40 
to assist in formation of the desired flow path. Finally, the cutter blade 
65 is provided with an upwardly inclined trailing edge 65d as shown. The 
trailing edge 65d creates a radially extending flow path which is 
relatively unobstructed behind the cutter blade 65 from the jets 100 to 
the annulus 56 and the upward inclination of the trailing edge 65d assists 
in withdrawing the cutter 64 from the soil when the direction of rotation 
of the Kelly 40 is reversed. 
Internally, each cutter blade 65 is provided with a pair of through bores 
106, 108 which in turn are intersected by vertical bores 110 into which 
individual jet nozzles 100 are threadedly connected. The through bores 
106, 108 terminate at the Kelly 40 which has been provided with a pair of 
fluid discharge ports 112 extending through the lower end of the Kelly 
wall so that high pressure fluid from the Kelly interior (or from a 
separate conduit if desired) is communicated to the jet nozzles 100. 
The speed of rotation of the Kelly 40 is continuously monitored and is 
increased with increasing moisture content of the soil as determined by a 
moisture content sensor so as to maintain the annular passageway 56 
unobstructed. It has been found that high water content in the soil has 
the effect of more rapidly clogging up the passageway 56. Rotation rates 
typically very from 5 RPM to 30 RPM with typical speeds for contaminant 
analysis comprising about 20-25 RPM and slower speeds being used for 
treatment of contaminated soil by repeated stripping or injection of 
treatment chemicals. Reversal of the direction of rotation when 
withdrawing the cutters 64 from the soil results in re-compaction of the 
soil to its initial condition. Also, higher speeds of rotation generally 
result in the intended volatilization of larger proportions of volatile 
contaminants. 
FIG. 7 shows the path of flow of the fluid ejected from the jets 100 first 
radially inwardly toward the Kelly 40 through the path created behind the 
trailing edge 65d of the cutter blade 65 and thence upwardly in the 
annulus 56 surrounding the Kelly 40 to the underside of the shroud 58 
which is maintained under negative pressure. Although the embodiment of 
the apparatus shown in FIG. 2 creates an annular flow passageway, it will 
be appreciated that, in its broadest aspects, the passageway need not be 
annular in cross section. For example, an I beam can be used instead of a 
round Kelly and the flow passageway created by rotation of the I beam 
would comprise the essentially rectangular cross section areas between the 
flanges and web of the I beam. 
Although the present invention is concerned primarily with methods and 
apparatus for obtaining data concerning soil contamination, when 
contaminants are found, treatment may be dictated. This treatment may 
consist of any combination of steps including the injection of additional 
hot air or steam for stripping of volatile contaminants, injection of 
treatment chemicals or biological treatment media, etc. Pressures of up to 
5000 psi are typically used with fluids at temperatures usually exceeding 
50.degree. C. to liberate volatile contaminants. Concern has been 
expressed that such high pressures may result in the recontamination of 
soil in the block or cylinder of soil above the cutter or in the 
contamination of previously cut adjacent cylinders. 
FIG. 8 shows a plan view of the pattern of treatment of a contaminated soil 
area using a pair of overlapping counter rotating cutter injectors 65, 65' 
enclosed in a single rectangular shroud 58. The frame 10, shroud 58 , 
Kelly or Kelleys 40 and the cutter or cutters 65, 65' are moved as a unit 
from one location to the next during soil analysis and treatment. As seen, 
the zones 140 overlap and the apparatus is positioned such that there is 
overlap between the boundaries 150 of the cylinders to be treated so that 
there are no untreated areas. The low pressure sink and flow path for 
volatile contaminants created by the present design ensures that the high 
pressures employed do not overpressurize the cylinders of soil being 
worked 152, 154 or contaminate adjacent previously treated soil cylinders 
156, 158 but instead, the volatile contaminants are immediately 
communicated to the shroud 58 where they can be analysed and scrubbed to 
remove contaminants. 
By way of example rather than limitation, apparatus intended primarily for 
contaminant analysis rather than treatment employs a cutter diameter of 
about 2'0" whereas an apparatus designed for treatment employs a 5'0" dual 
cutter arrangement wherein each cutter-injector is sized to treat a 
rectangular block or zone shown within the boundaries in FIG. 8 of 7'4" by 
about 4'0" or less. 
FIGS. 9 and 10 show a second embodiment of the invention which employs a 
Kelly 40 having downwardly extending teeth 159 on the lower end thereof 
and a plurality of high pressure fluid jet cutters 160 rather than the 
blade cutters 64 shown in FIGS. 5 and 6. It has been found that fluid jet 
cutters 160 which employ fluid pressures as high as 30,000 psi are capable 
of thoroughly cutting and agitating the soil for a sufficiently large 
radius outwardly from the Kelly 40 that radially extending rigid cutter 
blades 65 are not required. In the FIG. 9 embodiment, three vertically 
spaced rows each comprising four equally spaced jets 160 which are 
directed downwardly and outwardly as shown. Some of the jets 160 may be 
positioned at the lower end of the Kelly between the teeth 159 such that 
the rotating cutting teeth 159 shield and protect the lowermost jets 160. 
The high pressure fluid source 98' may comprise an ultrahigh pressure 
water pump of the type supplied by Admac Corp. of Kent, Wash. 
Alternatively, a high pressure air compressor may be utilized. The use of 
very high pressure has the added benefit of eliminating the need for means 
to heat the fluid at the surface to a temperature required to volatize the 
contaminants because the extremely high pressure fluid automatically 
undergoes a substantial temperature elevation during its forced passage 
through the nozzles. It is essential that the annulus cutter 50 be sized 
to cut an annulus 56 of sufficient cross sectional area to conduct all of 
the extremely high pressure fluid to the surface so as to avoid 
recontamination of adjacent cylinders caused by the extremely high 
pressure. 
High pressure fluid from the source 98' thereof is conducted to the 
individual jet cutters 160 by high pressure conduit 102' and a swivel 90' 
as seen in FIG. 2, the main difference being to ensure that sufficiently 
high pressure swivels and conduit connections are employed to withstand 
the higher pressures involved. 
Persons skilled in the art will readily appreciate that various 
modifications can be made from the preferred embodiment thus the scope of 
protection is intended to be defined only by the limitations of the 
appended claims.