Wu R.M.Feng W.H.Tsai I.H.Lee D.J.2019-05-142019-05-14199810614303https://scholars.lib.ntu.edu.tw/handle/123456789/408205This 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.Activated sludgeFloc permeabilityFreeze-thaw treatmentHydrodynamic drag forcejournal article10.2175/106143098X1236152-s2.0-0032215341https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032215341&doi=10.2175%2f106143098X123615&partnerID=40&md5=fa900b4d0bbafdab68e66e88ff00c86d