title: Modelling the degradation of endogenous residue and 'unbiodegradable' influent organic suspended solids to predict sludge production.
abstract: Activated sludge models have assumed that a portion of organic solids in municipal wastewater influent is unbiodegradable. Also, it is assumed that solids from biomass decay cannot be degraded further. The paper evaluates these assumptions based on data from systems operating at higher than typical sludge retention times (SRTs), including membrane bioreactor systems with total solids retention (no intentional sludge wastage). Data from over 30 references and with SRTs of up to 400 d were analysed. A modified model that considers the possible degradation of the two components is proposed. First order degradation rates of approximately 0.007 d(-1) for both components appear to improve sludge production estimates. Factors possibly influencing these degradation rates such as wastewater characteristics and bioavailability are discussed.
authors.affiliation: Université de Toulouse, Toulouse, France. Sperandio@insa-toulouse.fr
authors.forename: Mathieu
authors.initials: M
authors.lastname: Spérandio
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Labelle
authors.forename: Abdellah
authors.initials: A
authors.lastname: Ramdani
authors.forename: Alain
authors.initials: A
authors.lastname: Gadbois
authors.forename: Etienne
authors.initials: E
authors.lastname: Paul
authors.forename: Yves
authors.initials: Y
authors.lastname: Comeau
authors.forename: Peter L
authors.initials: PL
authors.lastname: Dold
mesh_terms: D019149:Bioreactors; D008567:Membranes, Artificial; D008962:Models, Theoretical; D012722:Sewage
chemical_list: D008567:Membranes, Artificial; D012722:Sewage