title: Modelling the effect of shear history on activated sludge flocculation.
abstract: The aim of this paper is to investigate the effect of shear history on activated sludge flocculation dynamics and to model the observed relationships using population balances. Activated sludge flocs are exposed to dramatic changes in the shear rate within the treatment process, as they pass through localised high and low mixing intensities within the aeration basin and are cycled through the different unit operations of the treatment process. We will show that shear history is a key factor in determining floc size, and that the floc size varies irreversibly with changes in shear rate. A population balance model of the flocculation process is also introduced and evaluated.
authors.affiliation: Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK. c.biggs@sheffield.ac.uk
authors.forename: C
authors.initials: C
authors.lastname: Biggs
authors.forename: P
authors.initials: P
authors.lastname: Lant
authors.forename: M
authors.initials: M
authors.lastname: Hounslow
mesh_terms: D019149:Bioreactors; D005427:Flocculation; D008962:Models, Theoretical; D012722:Sewage / Q000382:microbiology*; D033081:Shear Strength; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage