Permanent monitoring for containment structures such as subsurface tanks, geosynthetic lined ponds, landfills, mine tailings, dams, and heap piles is now a reality with HGI’s Leak Detection and Monitoring (LDM) system. The LDM system can be deployed in a range of environmental settings to monitor single, or multiple structures, installed at the surface or buried in the subsurface. The system can potentially incorporate currently installed infrastructure as sensors (electrodes) or completely design a custom sensor network where needed. Able to be deployed in any environment and monitor any type of waste, the LDM system has a number of in-built digital filters, allowing it to operate in noisy electrical environments of industrial sites where cathodic protection and other electrical noise are present.
Permanent Monitoring & the Hanford Nuclear Reservation
hydroGEOPHYSICS’ ‘Permanent Monitoring’ technology was developed through our many years of experience and ongoing work with storage tank characterization and monitoring, and has become a recognized leader in the application of geophysical methods to perform leak detection and monitoring at industrial complexes. HGI currently provides permanent, real-time monitoring to the Department of Energy (DOE) for nuclear waste storage tanks. The DOE Hanford Site in eastern Washington is home to 177 underground storage tanks, used from 1943 to 1986, to store waste generated during uranium processing. Many of the storage tanks have been confirmed, or assumed, to have leaked.
HGI provides permanent monitoring for leak detection at the Hanford Nuclear Reservation in Washington State…
The DOE is currently managing waste transfer to safer storage tanks, and monitoring tanks during the retrieval processes is critical. In 2000, HGI participated in a rigorous proof of concept test that included several national research labs and HGI was chosen, unanimously, by the EPA, DOE, and Washington Ecology for having the most accurate leak monitoring system. Consequently, our High Resolution Resistivity Leak Detection Monitoring (LDM) program to detect leaks has been in place since May of 2004. The system currently boasts a reliability record of 99.9% up-time, and is constructed with modular components and redundant systems. Based on the deployment and testing at the Hanford Site, the LDM system has a detection limit of 5 gallons within 30 minutes of leak onset for newly occurring leaks.
The monitoring program takes advantage of changes in electrical resistivity of the subsurface should a storage tank leak occur. Electrical current is transmitted on electrodes (such as available monitoring wells, installed surface and subsurface sensors), while voltages are measured on the storage tanks and surface and subsurface electrodes. As the data are acquired and processed, trends are evaluated for leaks and a web-based alarm system is in place should a leak be confirmed, providing around the clock, real-time assurance monitoring.
The monitoring program takes advantage of changes in electrical resistivity of the subsurface should a storage tank leak occur.
In the case of the Hanford Site, monitoring the electrical resistivity sensors consists of the storage tanks themselves and surrounding monitoring wells. HGI can use such existing metallic infrastructure, often present in industrial sites, to save on installation costs and logistic in setting up a monitoring network. In addition, HGI can design an optimized sensor network based on site logistics and requirements to ensure adequate coverage and to minimize costs on sites where infrastructure is absent or minimal. For long-term or permanent monitoring, a custom data acquisition system (DAS) is housed in a small trailer sited adjacent to the storage tank(s), providing real-time data processing and leak alert services. The site specific sensor network, which can be customizable in terms of number of channels, climate control, power supply to the site logistics, is connected back to the DAS. As the data are acquired and processed, they are graphed and the trends are evaluated for leaks. Our LDM AutoPro and AutoView Software provide automated data assessment, web based remote access, 24/7 system status monitoring, and daily expert visual assessment.