Site Characterization and Analysis Penetrometer System (SCAPS)

Description

The Site Characterization and Analysis Penetrometer System (SCAPS) is a rapid in-field soil and groundwater analysis system that provides cost-effective characterization of soil conditions to depths of up to a hundred feet or more. SCAPS uses a truck-mounted cone penetrometer system to directly push an instrumented probe into the ground for rapidly characterizing soil types and detecting and delineating the presence and extent of subsurface contamination. A variety of sensors can be attached to the probe to detect different compounds. Sensors to detect petroleum compounds and metals have been demonstrated (see descriptions of Laser Induced Fluorescence (LIF) and X-Ray Fluorescence).

Several different types of sensors and sampling tools mounted on the SCAPS are being tested. The thermal desorption and Hydrosparge sensors/samplers are used to detect volatile organic compounds (VOCs) in soil and groundwater. The thermal desorption sensor/sampler consists of a nose cone with a sampling chamber that can be opened to collect a soil sample. The sample is heated, volatilizing VOCs. Vapors are transported to the surface, where they are analyzed by a portable mass spectrometer. The Hydrosparge sensor/sampler inserts a sparge into a groundwater boring formed by the cone penetrometer. Using helium gas, it then purges the VOCs from the water, and transports them to the surface, where they are also analyzed by a portable mass spectrometer.

Sensors that detect explosive compounds (trinitrotoluene, Royal Demolition Explosive, and High Melting Explosive) and their degradation products in soil and water are also being demonstrated. A probe is equipped with a high-temperature heater for heating the soil. The probe warms the soil to a high temperature that is still below the ignition point of the explosive. The vaporized explosive compounds are collected and continuously monitored in the truck’s mobile laboratory.

Limitations and Concerns

SCAPS is an on-site characterization tool that can be used to delineate contaminant plumes and provide soil information. However, the sensors are field-screening tools and probably do not eliminate the need for laboratory analyses.

Some of the sensors and sampling devices may have difficulty detecting small concentrations.

Verification of the Hydrosparge sample is difficult to obtain, as only a small volume of water is sampled.

There are concerns that the thermal desorption sensor/sampler will have different efficiencies relative to soil types.

SCAPS has a limited use as a monitoring tool. A new hole has to be punched every quarter because the holes collapse after the penetrometer is withdrawn.

Applicability

This characterization technique can be used to detect explosive compounds, VOCs and petroleum products. It is adaptable to contaminant type.

Technology Development Status

The basic technology (i.e., the truck mounted cone penetrometer) is commercial. Sensors and sampling devices for VOCs and for explosive compounds are still being field-tested. Those for characterizing soil and identifying metals and petroleum are commercial.

Web Links

http://www.estcp.org/projects/cleanup/199603-TDS-v.cfm

http://www.estcp.org/projects/cleanup/199603-HS-v.cfm

http://www.estcp.org/projects/cleanup/199716o.cfm

http://www.environmental.usace.army.mil/library/success/itsucc/crrel/crrel.html

http://www.environmental.usace.army.mil/library/success/itsucc/donald/donald.html

http://www.environmental.usace.army.mil/library/success/itsucc/scaps/scaps.html

http://www.environmental.usace.army.mil/library/success/itsucc/turner/turner.html

http://enviro.nfesc.navy.mil/erb/erb_a/restoration/technologies/invest/access_tools/scaps.htm

Other Resources and Demonstrations

See related Technology Descriptions of the Cone Penetrometer, LIF Sensor, and XRF Analysis.

See Tri-Service Site Characterization and Analysis Penetrometer System-SCAPS: Innovative Environmental Technology from Concept to Commercialization, Jane W. Adams and George Robitaille, Army Environmental Center SFIM-AEC-ETT, January 2000.

See http://www.environmental.usace.army.mil/library/success/itsucc/scaps/scaps.html for DoD demonstrations of various sensors.

See http://www.wes.army.mil/el/elpubs/pdf/trirrp98-1.pdf for the development of a volatile organic compound analysis system (VOC sampler) by the U.S. Army Engineer Waterways Experiment Station (WES) for SCAPS.

See http://www.etd.ameslab.gov/etd/technologies/projects/esc/technologies/cptlif.html for a description of the GeoVIS probe developed by the Space and Naval Warfare Systems Center/San Diego. This system is used with SCAPS to obtain detailed information about subsurface soil characteristics on very small spatial scales. The GeoVIS device illuminates the surrounding soil through a sapphire window on the side of the probe. Video signals from the camera are returned to the surface over a 100 foot-long video cable, where they can be viewed in real time on a video monitor and documented on a video recorder. The standard GeoVIS optics system provides a viewing field of approximately 2 by 3 millimeters, and a magnification factor of 100 when viewed on a standard 13-inch monitor. GeoVIS has been used several times to characterize Non-Aqueous Phase Liquid contaminants at the former Alameda Naval Air Station.