Abstract

EPA’s Superfund Innovative Technology Evaluation Program evaluated the performance of HydroTechnics, Inc., flow sensors in measuring the three-dimensional flow pattern created by operation of the Wasatch Environmental, Inc. (WEI), ground water circulation well (GCW).

The GCW is a dual-screened, in-well, air-stripping system designed to remove volatile organic compounds from ground water. Operation of the GCW creates a ground water flow pattern that forms a three-dimensional regime known as a “circulation cell.” EPA’s evaluation of the GCW circulation cell involved use of in situ ground water velocity flow sensors that were developed at Sandia National Laboratories and manufactured by HydroTechnics, Inc. This Technology Evaluation Report documents and summarizes the findings of EPA’s evaluation of HydroTechnics’ flow sensors.

The flow sensors are in situ instruments that use a thermal perturbation technique to directly measure the velocity of ground water flow in unconsolidated, saturated, porous media. The manufacturer claims that the flow meter can measure horizontal and vertical flow rates and direction in the range of 0.01 to 2.0 feet per day (ft/day) (0.3 to 60.96 centimeters per second). The GCW is a patented system manufactured by WEI and was demonstrated at Cape Canaveral Air Station by the U.S. Air Force Center for Environmental Excellence (AFCEE).

AFCEE conducted a comprehensive evaluation of the GCW, including contaminant mass removal rates, ground water dye tracer studies, and numerical modeling. Demonstration data collected by AFCEE are documented separately in “Ground Water Circulation Well Technology Evaluation at Facility 1381, Cape Canaveral Air Station, Florida Technology, Summary Report.”

The primary conclusions of EPA’s evaluation of the HydroTechnics flow sensors include the following:

• During GCW operation, the ground water velocities measured by all seven sensors increased by more than 0.1 ft/day, indicating that the sensors were within the circulation cell established by the GCW and that the horizontal extent of ground water circulation was greater than 15 feet. Flow direction data further support the establishment of a circulation cell and demonstrate that all the flow sensors are within the horizontal extent of the ground water circulation cell.
• The demonstration data suggest that the flow sensors are responsive to changes in ground water flow conditions and can be used to help define and evaluate the three-dimensional flow patterns.

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Superfund Innovative Technology Evaluation

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