Facility and method for the detection and monitoring of plumes below a waste containment site with radiowave tomography scattering methods

• US 5,408,182 A
• Filed: 11/13/1992
• Issued: 04/18/1995
• Est. Priority Date: 11/13/1992
• Status: Expired due to Fees

• Current Assignee: Stolar Incorporated
• Original Assignee: Rim Tec, Inc. (Kyriba Corp.)
• Inventors: Mondt, William E., Stolarczyk, Larry G.
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): PATIDAR, JAY M
• Application Number:
  US07/975,776
• Time in Patent Office: 886 Days
• Field of Search: 324/338, 324/337, 324/334, 324/335, 324/339, 324/324, 324/325, 324/326, 324/342-343, 342/459, 342/463, 364/422
• US Class Current: 324/338
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves
• CPC Class Codes: G01V 3/34 Transmitting data to recording or processing apparatus; Recording data

Abstract

An embodiment of the present invention is a toxic waste containment facility subject to leaking hazardous plumes into soils beneath and adjacent to the site. The facility includes a plurality of substantially horizontal underground drillholes adjacent to and below a waste containment pit. A radio transmitter and antenna are placed in a first underground drillhole proximate to a surface waste containment site. A radio receiver and antenna are placed in a second underground drillhole opposite to the first drillhole. A position indicator is used for gauging a plurality of locations of the radio transmitter and antenna within the first underground drillhole and the radio receiver and antenna within the second underground drillhole. A data processing unit analyzes data received from radio receiver and antenna and position indicator to measure radio signal attenuation between the radio transmitter and antenna and radio receiver and antenna. The transmitted signal from the radio transmitter and antenna are synchronized by a signal from the data processing unit. Fiber optic cables are used to couple signals between the radio transmitter and antenna and radio receiver and antenna with the data processing unit. Along each path, the operating frequency is increased until all of the transmitted energy is absorbed along the path to maximize resolution. Tomographic techniques are used to translate the data collected from a variety of transmitter and receiver positions into attenuation profiles that can image a toxic plume beneath the containment pit.

Claims

1. A system for locating mobile plumes in soils beneath and adjacent to surface waste containment sites, comprising:

a radio transmitter and antenna for placement in a first underground drillhole proximate to a surface waste containment site;

a radio receiver and antenna for placement in a second underground drillhole opposite to said first drillhole relative to said surface waste containment site and for measuring phase and attenuation data related to received radio signals from the radio transmitter and antenna;

position determining means coupled to each of the radio transmitter antenna and radio receiver antenna for gauging a plurality of locations of said radio transmitter antenna within said first underground drillhole and a plurality of locations of said radio receiver antenna within said second underground drillhole and having an output for antenna position data;

a data processing unit coupled to the radio transmitter, the radio receiver and the positioning determining means for analyzing phase and attenuation data from the radio receiver together with said antenna position data from said output of the position determining means, and for synchronizing a transmitted signal from the radio transmitter and a local oscillator signal for the radio receiver;

soil plane imaging means and time keeping means connected to the data processing unit for constructing a time series of conductivity images of soil plane that includes the positions of the radio transmitter antenna and radio receiver antenna as represented in said antenna position output data; and

non-metallic means for coupling a plurality of signals between the radio transmitter and antenna and radio receiver and antenna with the data processing unit, wherein re-radiated radio signals are prevented.

2. The system of claim 1, further comprising:

frequency adjustment means connected to the radio transmitter and radio receiver for making an operational frequency of the radio transmitter and antenna and radio receiver and antenna adjustable wherein said operational frequency may be increased to a point at which said received radio signals from the radio transmitter and antenna are reduced substantially to zero due to increasing absorption by a material body located between the radio transmitter and antenna and radio receiver and antenna;

3. The system of claim 1, further comprising:

tomographic means coupled to the data processing unit and soil plane imaging means for generating radiowave attenuation and electrical conductivity maps of soil planes intersecting said first and second underground drillholes wherein a plume related to the surface waste containment site may be profiled if present.

4. The system of claim 1, wherein:

the radio receiver antenna comprises a gradiometer type of electromagnetic dipole antenna and the radio receiver includes computational means for summing and differencing signals from two identical, but opposite-polarity halves, wherein sensitivity to a scattered secondary field may be improved by use of said differencing signals.

5. The system of claim 4, further comprising:

tomography algorithmic means connected to the data processing unit and soil plane imaging means for processing data extracted from a reception of signals related to said scattered secondary field and for generating conductivity maps of regions between said underground drillholes.

6. The system of claim 1, further comprising:

transmitter calibrating means connected to the radio transmitter for adjusting and controlling the power output level and phase of a transmitter output carrier.

7. The system of claim 1, further comprising:

receiver calibrating means connected to the radio receiver for determining the input sensitivity and phase shifts of said receiver to received radio signals.

8. A system for locating mobile plumes in soils beneath and adjacent to a surface waste containment site, comprising:

a radio transmitter and antenna for placement in a first plurality of underground drillholes proximate to a surface waste containment site;

a radio receiver and antenna for placement in a second plurality of underground drillholes opposite to corresponding members of said first plurality of drillholes and relative to said surface waste containment site;

position determining means for gauging the location of said radio transmitter and antenna within said first plurality of underground drillholes and the location of said radio receiver and antenna within said second plurality of underground drillholes and having an output for antenna position data;

a data processing unit for analyzing data from radio receiver and antenna and position determining means and for measuring radio signal attenuation and carrier phase shift between the radio transmitter and antenna and radio receiver and antenna, and for synchronizing a transmitted carrier signal from the radio transmitter and antenna;

soil plane imaging means and time keeping means connected to the data processing unit for constructing a time series of conductivity images of a soil plane that includes the positions of the radio transmitter antenna and radio receiver antenna as represented in said antenna position output data; and

non-metallic means for coupling signals between the radio transmitter and antenna and radio receiver and antenna with the data processing unit.

9. The system of claim 8, further comprising:

three-dimensional tomographic means coupled to the data processing unit for generating radiowave attenuation maps of soil volumes having intersections with said first and second plurality of underground drillholes wherein a plume related to the surface waste containment site may be profiled in three-dimensions if present.

10. The system of claim 8, wherein:

the radio receiver antenna comprises a gradiometer type of electromagnetic dipole antenna and the radio receiver includes computational means for summing and differencing signals from two identical, but oppositely wound parts, wherein sensitivity to a scattered secondary field may be improved by use of said differencing signals.

11. The system of claim 10, further comprising:

tomography algorithmic means connected to the data processing unit for processing data extracted from a reception of signals related to said scattered secondary field and for generating conductivity maps of regions between said underground drillholes.

12. The system of claim 10, further comprising:

frequency adjustment means connected to the radio transmitter and the radio receiver for making an operational frequency of the radio transmitter and antenna and radio receiver and antenna adjustable wherein said operational frequency may be increased to a point at which said received radio signals from the radio transmitter and antenna are reduced substantially to zero due to increasing absorption by a material body located between the radio transmitter and antenna and radio receiver and antenna;

13. A toxic waste containment facility subject to leaking hazardous plumes into soils beneath and adjacent to the site, comprising:

a plurality of substantially horizontal underground drillholes adjacent to and below a waste containment pit;

a radio transmitter and antenna for placement in a first of said underground drillholes proximate to said waste containment pit;

a radio receiver and antenna for placement in a second of said underground drillholes opposite to said first drillholes;

position determining means for gauging a plurality of locations of said radio transmitter and antenna within said first underground drillhole and of said radio receiver and antenna within said second underground drillhole and having an output for antenna position data;

a data processing unit for analyzing data from radio receiver and antenna and position determining means and for measuring radio signal attenuation between the radio transmitter and antenna and radio receiver and antenna, and for synchronizing a transmitted carrier signal from the radio transmitter and antenna to a local oscillator included in the receiver for synchronous operation;

soil plane imaging means and time keeping means connected to the data processing unit for constructing a time series of conductivity images of a said plane that includes the positions of the radio transmitter antenna and radio receiver antenna as represented in said antenna position output data; and

non-metallic means for coupling signals between the radio transmitter and antenna and radio receiver and antenna with the data processing unit.

14. The facility of claim 13, wherein:

the radio transmitter includes a phase synchronous continuous wave transmitter; and

the data processing unit comprises means for accepting as data a plurality of phase shift measurements.

15. The facility of claim 13, further comprising:

transmitter calibrating means connected to the radio transmitter for adjusting and controlling the power output level and phase of said transmitted carrier signal from the radio transmitter and antenna; and

receiver calibrating means connected to the radio receiver for determining the input sensitivity and phase shifts of the receiver to a received radio signal.

16. A toxic waste containment facility subject to leaking hazardous plumes into soils beneath and adjacent to the site, comprising:

a plurality of substantially horizontal underground drillholes adjacent to and below a waste containment pit;

a phase synchronous continuous wave radio transmitter and antenna for placement in a first of said underground drillholes proximate to said waste containment pit;

a radio receiver and an electromagnetic gradiometer type dipole antenna for placement in a second of said underground drillholes opposite to said first drillholes and including means for summing and differencing signals from two identical, but oppositely wound parts of the antenna, wherein sensitivity to a scattered secondary field may be improved by use of said differencing signals;

transmitter calibrating means for adjusting and controlling the power output level and phase of a transmitted carrier signal from the radio transmitter and antenna;

receiver calibrating means for determining the input sensitivity and phase shifts of the receiver to a received radio signal;

frequency adjustment means for making an operational frequency of the radio transmitter and antenna and radio receiver and antenna adjustable wherein said operational frequency may be increased to a point at which said received radio signals from the radio transmitter and antenna are reduced substantially to zero due to increasing absorption by a material body located between the radio transmitter and antenna and radio receiver and antenna;

position determining means for gauging a plurality of locations of said radio transmitter and antenna within said first underground drillhole and of said radio receiver and antenna within said second underground drillhole and having an output for antenna position data;

a data processing unit for analyzing data from radio receiver and antenna and position determining means and for measuring radio signal attenuation between the radio transmitter and antenna and radio receiver and antenna, and for synchronizing a transmitted carrier signal from the radio transmitter and antenna to a local oscillator included in the receiver for synchronous operation, and for accepting as data a plurality of phase shift measurements from the receiver;

soil plane imaging means and time keeping means connected to the data processing unit for constructing a time series of conductivity images of a soil plane that includes the positions of the radio transmitter antenna and radio receiver antenna as represented in said antenna position output data; and

non-metallic means for coupling signals between the radio transmitter and antenna and radio receiver and antenna with the data processing unit.

17. A method of monitoring chemical waste containment sites for underground seepage of plumes, the method comprising the steps of:

synchronizing a carrier frequency of a transmitter and a local oscillator of a receiver able to receive said carrier frequency such that a phase shift of a radiowave propagation between said transmitter and receiver may be measured;

calibrating a power output level of said transmitter and a reception sensitivity of said receiver such that attenuation of said radiowave propagation between said transmitter and receiver may be measured;

positioning said transmitter in a first underground drillhole proximate to a chemical waste containment site;

positioning said receiver in a second underground drillhole proximate to a chemical waste containment site;

measuring phase shift and attenuation of a plurality of radiowave propagations between said transmitter and receiver at a plurality of positions of said transmitter and receiver within their respective first and second underground drillholes;

soil plane imaging data representing antenna position, phase shift and attenuation obtained from the step of measuring with a data processing unit and thereafter constructing a time series of conductivity images of a soil plane that includes the positions of said radio transmitter antenna and said radio receiver antenna as represented in said antenna position output data; and

determining a set of electrical parameters related to an image plane of the underground geology between said plurality of positions of said transmitter and receiver.

18. The method of claim 17, wherein:

the step of determining includes calculating the phase shift, ##EQU19## where, α

is an attenuation constant, and β

is a phase constant.

19. The method of claim 17, further comprising the subsequent step of:

tomographically constructing a contour map of said underground geology using a known k^th ray path distance (d_ijk) through each pixel to determine the average attenuation rate (α

_ij) in each pixel from a measured total loss (α

r)_k, obtained in the step of measuring phase shift and attenuation, on the k^th path, according to;

##EQU20##

20. The method of claim 17, further comprising the subsequent steps of:

positioning said transmitter in a third underground drillhole proximate to said chemical waste containment site;

positioning said receiver in a fourth underground drillhole proximate to said chemical waste containment site;

measuring phase shift and attenuation of said radiowave propagation between said transmitter and receiver at a plurality of positions of said transmitter and receiver within their respective first through fourth underground drillholes; and

determining a set of electrical parameters related to a plurality of image planes of the underground geology between said plurality of positions of said transmitter and receiver; and

drawing three-dimensional images of said underground geology using tomographic reconstruction wherein plumes may be identified and tracked over time.

21. The method of claim 17, further comprising the preliminary step of:

increasing an operational frequency of said radio transmitter and antenna and radio receiver and antenna to a point (FT) at which a received radio signal from the radio transmitter and antenna is reduced substantially to zero due to increasing absorption by a material body located between said first and second underground drillholes; and

storing data related to said point F_T for tomographic processing.

22. The method of claim 17, further comprising the subsequent step of:

processing data corresponding to a signal received by a differencing electromagnetic gradiometer dipole antenna included in said receiver and related to a scattered secondary field for construction of a conductivity map of a region between said drillholes.