An estimate of activated-sludge floc permeability: A novel hydrodynamic approach
Journal
Water Environment Research
Journal Volume
70
Journal Issue
7
Pages
1258-1264
Date Issued
1998
Author(s)
Abstract
This work estimates the interior permeability of waste activated sludge flocs by observing the motion of individual flocs moving vertically toward an impermeable flat plate. Through a comparison of experimental data with theoretical predictions in the literature, floc permeabilities of original sludge and freeze-thaw-conditioned sludges are found to be 0.7 X 10-7 to 5 x 10-7 m2 and 0.9 x 10-9 to 6 X 10-9 m2, respectively. Moreover, incorporating inertial effect delays the influence of the flat plate, thereby causing the creeping-flow-based correlation to fail.This work estimates the interior permeability of waste activated sludge flocs by observing the motion of individual flocs moving vertically toward an impermeable flat plate. Through a comparison of experimental data with theoretical predictions in the literature, floc permeabilities of original sludge and freeze-thaw-conditioned sludges are found to be 0.7 ¡Ñ 10-7 to 5 ¡Ñ 10-7 m2 and 0.9 ¡Ñ 10-9 to 6 ¡Ñ 10-9 m2, respectively. Moreover, incorporating inertial effect delays the influence of the flat plate, thereby causing the creeping-flow-based correlation to fail.
Subjects
Activated sludge
Floc permeability
Freeze-thaw treatment
Hydrodynamic drag force
Type
journal article