In-Line Measurement of Trichloroethylene Vapors Using Tin Dioxide Sensors |
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| Authors: | G Heron M van Zutphen C G Enfield |
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| Institution: | Gorm Heron is a research engineer at the University of California, Berkeley. He has a Ph.D. in environmental science and an M.S. in civil engineering from Technical University of Denmark. His e-mail address is;Marcus van Zutphen is an engineer at Netherlands Institute of Applied Geoscience TNO (Schoemakerstraat 97, NL-2628 VK, Delft, The Netherlands). He has an M.S. in engineering from the Technical University of Delft, The Netherlands. His e-mail address is .;Carl G. Enfield is a senior environmental scientist at the U.S. Environmental Protection Agency (Cincinnati, Ohio). He has a Ph.D. in soils, water, and engineering from the University of Arizona. His e-mail address is . |
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| Abstract: | During thermally enhanced in situ remediation of soils and ground water, gas streams are generated with varying temperatures, moisture content, and organic compound concentrations. In this study, we evaluated the performance of tin dioxide sensors for measuring trichloroethylene (TCE) concentrations in gas streams from a thermally enhanced soil vapor extraction system. Temperature, pressure, moisture content, and vapor flow rates affected the resistivity of the sensors, and thus the signal. When fluctuations in these parameters were eliminated by condensing excess water and healing to a constant temperature prior to measurement, the sensors provided reliable in-line measurement of TCE concentrations. Gas tracers such as methane were easily monitored in-line, providing quick and inexpensive data on subsurface vapor flow velocities and direction. |
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