Estimation of floc permeability and porosity
Journal
Journal of the Chinese Institute of Chemical Engineers
Journal Volume
34
Journal Issue
2
Pages
275-280
Date Issued
2003
Author(s)
Abstract
This paper briefly reviewed the progress made recently to the estimation of hydrodynamic permeability of sludge flocs, which is essential for determining the extent of advection flow through the floc interior. The large pores mainly contribute the hydrodynamic permeability of sludge floc through which the fluid could readily flow. Permeability models that assume a homogeneous floc interior normally yield marked uncertainties in model outputs. Wu et al. (1998) proposed a hydrodynamic approach for estimating the hydrodynamic permeability that considers the response of the sludge floc when moves toward a flat plate. The floc permeability for waste activated sludge was noted higher than the cupric hydroxide sludge, while the polyelectrolyte flocculation and fluid shear could reduce the permeability. The bubble-tracking technique describes the fluid flow field around and through the floc interior. The existence of advection flow is noted unexceptional. The misuse of permeability model has been demonstrated with a case study leading to the floc porosity based on free-settling test.
Subjects
Advection flow
Bubble-tracking
Floc
Hydrodynamics
Permeability
Porosity
Type
journal article