SEAMIST Instrumentation/Sampling System
The SEAMISTª Instrumentation/Sampling System is designed to replace the traditional method of installing and operating a common monitoring well. The old method involves drilling a hole and forcing a metal casing down the hole to keep the walls from collapsing. The SEAMIST Instrumentation/Sampling System keeps the walls of the well from collapsing with an inexpensive membrane made of a coated fabric. The membrane is airtight. Driven by air or water pressure into the borehole, it presses up against the walls. This effectively lines the surface, prevents flow into the hole, and maintains integrity of the hole. The SEAMIST membrane can travel into vertical and horizontal holes, traversing curves and penetrating to a depth or length of over 200 feet. After the hole is in place, various types of instruments can be fed into it to monitor and sample hydrological and chemical parameters.
Limitations and Concerns
A major limitation is that the borehole must remain open long enough for the system to be installed. Deep boreholes often collapse before the SEAMIST membrane can be put in place.
SEAMIST cannot be used at some sites. The liner does not seal well in formations that contain large cobbles.
Some of the sensors used with SEAMIST have been plagued with difficulties.
The best applications of SEAMIST technology are at sites where contamination is relatively deep (greater than 50 ft) and boreholes can be kept open long enough for installation of the membrane; at sites where different characterization technologies are needed; and at sites where measurements must be taken at different depths. A well with the SEAMIST membrane can also be used to install electrodes for geophysical measurements. It may also be used to inject fluids into the subsurface—for example nutrients for microorganisms or tracers.
Additional applications may include: mapping the vertical distribution of contaminant plumes and radioactive isotopes; monitoring plume migration beneath surface obstacles; monitoring in-situ bioremediation progress; and towing moisture monitors to map saturation distributions.
Technology Development Status
The technology is commercially available.
Other Resources and Demonstrations
See http://www.osti.gov/bridge/servlets/purl/224259-h0N0xq/webviewable/ for a description of demonstrations at Department of Energy sites.