Information Last Revised: 19 July 1993
TTP Reference Number: AL221114
1. Technical Name of Technology: Advanced In Situ Moisture Logging System
2. Common Name of Technology: Moisture Logging
3. PI and Telephone No: Robert Knowlton, 505-848-0425, Fax:505-848-0417
4. Affiliation: Department 7723, Sandia National Laboratories-NM
5. Technology Category: Characterization
6. Developers: Sandia National Laboratories
7. Application
7.1. Where (in-situ/ex-situ): In Situ
7.2. Media: Arid Soils
7.3. Targeted Contaminants: detect the change in fluid concentrations attributable to leaks/contaminant migration from a waste site
8. Scope of project (feasibility study, treatability, bench, pilot, field):
Field demonstration and testing.
9. Integrated Demonstration (ID) Need/Requirements:
Mixed Waste Landfill Integrated Demo: Need 1 - In Situ Sensors and Sampling Devices; Need 5 - Vadose Zone Post-Closure Monitoring. A method is needed to demonstrate and evaluate a self-contained nuclear moisture/density probe for use in directionally drilled access tubing beneath waste sites for the purpose of leak/contaminant detection and post-closure monitoring.
10. Objective
10.1. Objective of technology (e.g., This technology will destroy VOCs in groundwater.):
To demonstrate and evaluate a self-contained nuclear moisture/density probe for use in directionally drilled access tubing beneath waste sites for the purpose of leak/contaminant detection and post-closure monitoring.
10.2. Baseline (baseline technology to which it is compared):
Conventional Cabled Nuclear Logging Devices (Conv. Logging)
11. Process Description:
The neutron source/detector consists of an Americium/Beryllium combination (10 mCi). The source and detector are located in close proximity to each other, and the probe counts thermalized "slow" neutrons that have contacted hydrogen atoms, which is significantly different from the mineral and oil industries, where the source and detector are widely spaced, and the probe counts "fast" neutrons. The Troxler count ratio is generally linear with respect to percent moisture. Its configuration allows for quantification of the moisture content to within plus or minus 2% volumetric water content, when calibrated to a given soil and has an approximate radius of influence of about 30 cm. The mineral/oil industry probes integrate soil moisture over much larger volumes, with much less accuracy and precision. The gamma source, for measuring soil density, is an 8 mCi cesium-137 configuration.
The conventional means of deploying such a probe is to lower a logging tool down an access tube to a depth of several meters or possibly tens of meters The electronics to operate and process data from the probe are located in a housing which sits at the top of the access casing. The cable used to lower the probe down the access tube serves as both support cabling and electronic communications. The signal noise ratio may become impaired with increasing length of the cable Therefore, there exists a practical limitation on hole depth. The new Troxler probe is self-contained. In other words, the electronics required to take a reading and to program subsequent readings of moisture content and soil density are contained within the housing of the device itself. The probe is drawn through an access tube via a support cable which requires no electronic communications to the top of the casing. Therefore, length of the access tubing is not prohibitive, and long horizontal tubes may be used if a delivery system is engineered properly. The proposed choice for a delivery system is to employ a constant velocity winch, or one which can be hooked up to a data logger or laptop computer to record cable take-up rate and time and.or length. Such a system has just become available from Mount Sopris Instrument Co., Inc., Golden, CO. Other devices exist to monitor in situ moisture content and soil density but are general point source devices. The advantage of a downhole logging device is the continuous data collection along the length of the access tubing. Therefore a greater spacial coverage is obtained. With the advent of the horizontal/directional drilling technologies, the applications of the downhole self-contained monitoring devices becomes significantly enhanced. One could envision a network of horizontally drilled access tubes emplaced beneath a facility which, coupled with the right monitoring technology, could provide an early warning system for leak detection. In addition, information from downhole logging devices is essential in evaluating the performance of such remedial alternatives as capping or soil venting strategies, and as input to risk assessment modeling methodologies. In deep vadose zone regimes, this type of device/monitoring system might be use in lieu of expensive monitor well installations, if the regulators will buy in. The tool being evaluated with this funding will provide a self-contained neutron/gamma moisture/density probe for use in vertical or horizontal access tubing of practically any length. The tool may be used at practically any waste site throughout the DOE complex where moisture content and.or soil density data are needed whether for leak detection or performance of a facility.
11.1. Input:
Device measures moisture content and soil density around access tubing within a soil/rock media
11.2. Output:
Determination of changes in fluid potential which in turn is indicative of leakage/contaminant movement from a waste site
12. Summary of Technology Advantages (relative to the baseline: faster, better, cheaper, safer):
Device is self-contained and programmable, making the application faster and easier, with longer access tubing, than conventional technology. Affords an opportunity for an alternative vadose zone monitoring scheme, in lieu of costly monitor well networks.
13. Limitations of Technology (relative to the baseline: faster, better, cheaper, safer):
None
14. Major Technical Challenges:
Reproducibility of results, and adequately defining the accuracy and precision of the method. Further, the delivery system needs to be developed.
15. Technical Effectiveness:
15.1. Performance:
15.1.1. Remaining Contamination: (contamination mobility reduction, volume reduction, toxicity reduction)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2. Process Waste
15.1.2.1. Status of waste (mobility, volume, hazard, recyclability)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2.2. Treatment (needed, available)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2.3. Decontamination / Decommissioning
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.2.4. Disposal (needed, available)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
15.1.3. Practicality
15.1.3.1. Foreclose Future Options
Summary (20 words or less): Does not reduce future options. Is only a characterization technology.
Further Description (unlimited length):
15.1.3.2. Reliability
Summary (20 words or less): Quite reliable
Further Description (unlimited length):
15.1.3.3. Failure Control
Summary (20 words or less): If the tool becomes stuck inside the hole, there are still a number of options.
Further Description (unlimited length): If a surface to surface hole is being used, the tool may still be dislodged by pulling on it from either end and retrieving it. If that fails, it is possible that the directional drilling technology could somehow be employed to retrieve the moisture logging tool. In the event that that fails, the last resort would be to excavate out the tool, if there are not too many contaminants in the soil above it. Typically, it would be about thirty to forty feet down.
15.1.3.4. Ease of Use
Summary (20 words or less): Easy, but need to exercise caution when using nuclear device
Further Description (unlimited length):
15.1.3.5. Infrastructure
Summary (20 words or less): Only a borehole is necessary. Beyond that, the device is self-contained.
Further Description (unlimited length):
15.1.3.6. Versatility
Summary (20 words or less): Used in vertical as well as horizontal access tubes. Provides an alternative vadose zone monitoring scheme, instead of costly monitor well networks.
Further Description (unlimited length): Moisture/density logging is the only demonstrated technology to date capable of detecting the potential for leaks/contaminant movement from waste sites.
15.1.3.7. System Compatibility
Summary (20 words or less): The tool is self-contained.
Further Description (unlimited length):
15.1.3.8. Off-the-Shelf (procurement ease)
Summary (20 words or less): Available for purchase or lease from Troxler Electronics Laboratories, Inc.
Further Description (unlimited length):
15.1.3.9. Maintainability
Summary (20 words or less): No user serviceable parts; however, the user can recalibrate the tool if needed.
Further Description (unlimited length):
15.1.3.10. Safety Measures
Summary (20 words or less): Standard precautions for nuclear logging devices necessary.
Further Description (unlimited length):
15.1.4. "Works" (functions as intended):
Summary (20 words or less): The first trials found that the device needs alteration for use in the field (i.e., needs to be "ruggedized").
Further Description (unlimited length): Subsequent testing shows it works as intended. Deployment methods are under evaluation.
15.2. Cost
15.2.1. Start-Up Cost
Summary (20 words or less): $18K for probe, $16K for winch. Due to the large start-up costs, it is likely that Troxler will make this tool available through a leasing program.
Further Description (unlimited length):
15.2.2. Operations and Maintenance Cost
Summary (20 words or less): No routine maintenance
Further Description (unlimited length):
15.2.3. Life-cycle cost
Summary (20 words or less): Above.
Further Description (unlimited length):
15.3. Time
15.3.1. Years Until Available
Summary (20 words or less): At the end of FY93
Further Description (unlimited length):
15.3.2. Speed/Rate
Summary (20 words or less): Variable. It can be set for different counting times. Typically, however, it takes fifteen minutes per one hundred feet of tube.
Further Description (unlimited length):
15.3.3. Years to Finish
Summary (20 words or less): It depends on the length of the tube.
Further Description (unlimited length):
16. Environmental Safety and Health
16.1. Worker Safety
16.1.1. Exposure to Hazardous Materials/Hazards
Summary (20 words or less): Nuclear logging tool, with low-level radiation hazard.
Further Description (unlimited length):
16.1.2. Physical Requirements
Summary (20 words or less): Storage in shielded case, with proper security
Further Description (unlimited length):
16.1.3. Number of People Required
Summary (20 words or less): One to two
Further Description (unlimited length):
16.2. Public Health and Safety
16.2.1. Accidents
Summary (20 words or less): None expected
Further Description (unlimited length):
16.2.2. Routine Releases
Summary (20 words or less): None
Further Description (unlimited length):
16.2.3. Transportation
Summary (20 words or less): Must meet DOT requirements for nuclear materials
Further Description (unlimited length):
16.3. Environmental Impacts
16.3.1. Ecological Impacts
Summary (20 words or less): The source is self-contained and totally sealed.
Further Description (unlimited length):
16.3.2. Aesthetics
Summary (20 words or less): Tool makes no noise. The winch and the generator for the winch if used may make some noise.
Further Description (unlimited length):
16.3.3. Natural Resources
Summary (20 words or less): Not applicable
Further Description (unlimited length):
16.3.4. Energy Demands
Summary (20 words or less): 7 volts of direct current (DC)
Further Description (unlimited length):
17. Socio-Political Interests
17.1. Public Perception
17.1.1. Proponent Reputation
Summary (20 words or less): Troxler, in the soil physics community and in the transportation engineering community, is recognized as one of the standard bearers in the field.
Further Description (unlimited length): Troxler is the only company with a self-contained moisture logging probe.
17.1.2. Familiarity / Understandability
Summary (20 words or less): It should not be difficult to explain, nor controversial, as it is only a characterization technology.
Further Description (unlimited length):
17.2. Tribal Rights / Future Land Use
17.2.1. Capacity for Unrestricted Use (terrestrial, aquatic)
Summary (20 words or less): Not applicable
Further Description (unlimited length):
17.3. Socio-Economic Interests
17.3.1. Economic Impacts
Summary (20 words or less): None
Further Description (unlimited length):
17.3.2. Labor Force Demands
Summary (20 words or less): None
Further Description (unlimited length):
18. Regulatory Objectives
18.1. Compatibility with Cleanup Milestones
Summary (20 words or less): This device will aid in the achievement of cleanup milestones.
Further Description (unlimited length):
18.2. Regulatory Infrastructure / Track Record
Summary (20 words or less): Nuclear logging is recommended by EPA
Further Description (unlimited length): Loren Everett, a professor at UC-SB who contracts with the EPA to write guidance documents includes neutron logging as a characterization method.
18.3. Regulatory Compliance
Summary (20 words or less): Nuclear logging is recommended by EPA
Further Description (unlimited length): Regulatory approval is not specifically required for this type of monitoring technology, unless it is proposed as an alternative monitoring strategy to an expensive monitoring well network.
19. Industrial Partnerships
19.1. Company Names:
EPA Environmental Monitoring Systems Laboratory, Las Vegas, NV; Troxler Electronics Laboratories, Inc., Research Triangle Park, NC; Mount Sopris, Inc., Golden, CO; University of California at Santa Barbara
19.2. Rationale:
19.3. Contract Mechanism:
19.4. Other Potential Companies:
19.5. International:
20. Intellectual Property
20.1. Patent Ownership:
Troxler Electronics Laboratories, Inc. "Apparatus and Method for Detecting Subterranean Leakage from a Large Storage Vessel"
20.2. Other Owners:
20.3. Patent Number:
5155356
21. Cost Sharing:
Field testing setup will be shared with the Sandia National Laboratories Environmental Restoration Program.
22. Background on this technology (Where did the idea come from? Who else is doing similar work? What have the results been to date? What is the most significant competitor to this technology?):
This idea arose from a familiarity with logging tools and needs. It is unknown whether others are conducting similar work. Other logging tool manufacturers may develop these tools as well, b to date have not. The results so far have been excellent, as hoped.
23. Reference Documents:
Kramer, John, Lorne Everett, and Stephen Collen. "Innovative Vadose Zone Monitoring at a Landfill Using the Neutron Probe." presented at the Outdoor Action Conference. 24-25 May 1991. Las Vegas: Outdoor Action Conference, 1991.