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Limitations of ROI Testing for Venting Design: Description of an Alternative Approach Based on Attainment of a Critical Pore‐Gas Velocity in Contaminated Media
Author(s) -
DiGiulio Dominic C.,
Varadhan Ravi
Publication year - 2001
Publication title -
groundwater monitoring and remediation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 47
eISSN - 1745-6592
pISSN - 1069-3629
DOI - 10.1111/j.1745-6592.2001.tb00635.x
Subject(s) - permeability (electromagnetism) , petroleum engineering , relative permeability , volumetric flow rate , computation , critical ionization velocity , simulation , environmental science , computer science , mechanics , geology , geotechnical engineering , chemistry , algorithm , biochemistry , physics , membrane , porosity
Abstract We utilize data from a Superfund site where radius of influence (ROI) testing was conducted in support of a venting design to describe limitations of ROI evaluation in more detail than has been done previously, and to propose an alternative method of design based on specification and attainment of a critical pore‐gas velocity in contaminated subsurface media. Since accurate gas permeability estimation is critical to pore‐gas velocity computation, we assess the usefulness of ROI testing data on estimation of radial permeability, vertical permeability, and leakance. We apply information from published studies on rate‐limited vapor transport to provide the basis for selection of a critical design pore‐gas velocity for soils at this site. Using single‐well gas flow simulations, we evaluate whether this critical pore‐gas velocity was achieved at measured ROIs. We then conduct a series of multi‐well gas flow simulations to assess how variation in anisotropy and leakance affect three‐dimensional vacuum and pore‐gas velocity profiles and determination of an ROI. Finally, when attempting to achieve a critical design pore‐gas velocity we evaluate whether it is more efficient to install additional wells or pump existing wells at a higher flow rate.