Negative Ion Sensors for Real-Time Downhole DNAPLs Detection
Final rept. 12 May 1998-11 May 2001
DAKOTA TECHNOLOGIES INC FARGO ND
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This final report summarizes the findings of a three-year RD project aimed at improved methodology for locating chlorinated solvent contamination in the subsurface. Current subsurface sampling methods soil cores, split spoon provide widely spaced data points for economic considerations and may be less than accurate because of the volatility of some species. Direct detection of subsurface contamination alleviates many of these negative factors, but itself brings additional difficulties such as contending with the water table. Direct push technology offers a promising alternative to the conventional approaches and has proven very useful in characterizing subsurface hydrocarbon contamination using laser induced fluorescence technology. The effort reported here employs a patented Membrane Interface Probe MIP to allow mass transfer across the MIP from the soil matrix to a carrier gas internal to the cone penetrometer. Placing the detector downhole allows immediate detection of the volatile compound requiring only the electrical signal to be transferred to the surface. During this effort three technologies were demonstrated for subsurface detection, a halogen specific detector XSD, a photoionization detector PID, and a photoemissive electron capture detector PE-ECD. Each was demonstrated at known contaminated sites with favorable results.
- Physical Chemistry
- Electrical and Electronic Equipment
- Water Pollution and Control