Our Portfolio: Sensors Projects

CMST Index | Sensors | SCFA

Color Recognition Sensor for Direct Push Systems

Information
Resources

Technology
Summary Sheet

Technology
Deployment
Fact Sheets:
AR #1592

Images

 

Tech ID: 2949
Project Overview
The Color Recognition Sensor is deployed using the Cone Penetrometer Technology (CPT). It provides a continuous quantitative record of subsurface color. Color changes can indicate the presence of thin layers, blobs, etc. of subsurface contaminants, in addition to revealing the subsurface structure. The CRS is typically combined with a fluorescence monitor which can indicate the presence of organic constituents. Output typically consists of a continuous log showing soil color overlaid with a fluorescence intensity chart; the fill color of the intensity chart provides a crude indication of the nature of the constituent producing the fluorescence.

Technology Description
The Color Recognition Sensor is combined with a fluorescence sensor in Dakota Technology's Hyperlogger. This device makes optical measurements through a sapphire window in a cone penetrometer probe. These are converted to electrical signals and relayed to a lap-top computer on the surface. Measurements are made, stored, and analyzed in real time during a CP push. At the standard push rate of 2 cm/s, spatial resolution approaching 0.5 cm can be achieved, allowing detection and even rudimentary identification of thin layers, blobs, and ganglia of DNAPLs and other organic constituents in the subsurface. The fluorescence module measures emissions at three wavelengths, which are combined into a false color image: 350 nm is assigned to blue, 420 nm to green, and 480 nm to red. The resulting intensity/'spectral' log is superimposed on a background showing soil color; these are plotted as a function of depth. In the image shown in the Technology Summary Sheet, the `blue' fluorescence peak at a depth of 63.3-64.3 ft corresponds to light colored soils. The `blue' false-color could indicate a kerosene type product, although precise identification is not possible with only three emission channels. The Membrane Interface Probe (OST 2950) could be exchanged for the Hyperlogger to sample the contaminant and provide precise identification of the organic constituent(s) present at this depth.

Return to Top