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Air Channel Formation, Size, Spacing, and Tortuosity During Air Sparging
Author(s) -
Elder Carl R.,
Benson Craig H.
Publication year - 1999
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.1745-6592.1999.tb00231.x
Subject(s) - air sparging , tortuosity , sparging , volume (thermodynamics) , range (aeronautics) , secondary air injection , channel (broadcasting) , materials science , particle size , air gap (plumbing) , mineralogy , mechanics , composite material , geology , chemistry , porosity , physics , engineering , ecology , contamination , biology , environmental remediation , paleontology , quantum mechanics , electrical engineering , thermodynamics
Characterizing mass transfer during in situ air sparging requires knowledge of the size, shape, and interfacial area of air channels. These characteristics were determined by analysis of digital images of air channels passing through submerged glass beads having particle size in the sand range. Pore‐scale channeling occurred in all cases. The analysis showed that the air channels were narrower, more tortuous, more closely spaced, and moved nearly vertically through the coarser media. In the finer media, air channels had larger diameter, were spaced further apart, and passed nearly horizontally through the media. The mean diameter of the channels varied between 2.8 and 8.1 mm, and the mean spacing varied between 8.3 and 19.4 mm. Estimates of the area of the air‐water interface per unit volume of soil (a 0 ), computed using data from the digital images and an assumed arrangement of channels, ranged from 0.02 to 0.2 mm 2 /mm 3 . Larger a 0 were obtained for coarser media and uniformly graded media. These estimates of a 0 compare well with published values for common packed‐column materials and for unsaturated soils.