title: Sludge reduction via biodegradation of the endogenous residue (XE): experimental verification and modeling.
abstract: The feasibility of sludge reduction via the XEbiodegradation process was explored both experimentally and through modeling, where the main focus was on determining the value of the bEparameter (first order degradation of XE) from a continuous process. Two activated sludge (AS) systems (30 L) were operated in parallel with synthetic wastewater during 16 months: a conventional activated sludge (CAS) system and a modified low-sludge production activated sludge (LSP-AS) process equipped with a side-stream digester unit (DU). First, the long term data of the CAS reactor (1 year) were used to calibrate the ASM model and to estimate the heterotrophic decay constant of the cultivated sludge (bH= 0.29 d-1, death-regeneration basis). Second, pre-simulations were performed to design the LSP-AS system and to estimate the DU volume required (40 L), to avoid XEaccumulation in the process. Third, the LSP-AS process was built, put in operation and monitored for more than 9 months. This allowed assessment of the actual behavior of the quasi-complete solids retention system. Once calibrated, the modified AS model estimated the value of the bEparameter to be in the range of 0.003-0.006 d-1, satisfactorily describing the overall sludge yield reduction of up to 49% observed in the experiments.
authors.affiliation: Universidad Autonoma del Estado de Mexico (UAEM), Apdo postal 367, Toluca C.P. 50091, Mexico E-mail: c-fa-ll@hotmail.com.
authors.forename: Cheikh
authors.initials: C
authors.lastname: Fall
authors.affiliation: Universidad Autonoma del Estado de Mexico (UAEM), Apdo postal 367, Toluca C.P. 50091, Mexico E-mail: c-fa-ll@hotmail.com.
authors.forename: Ericka L
authors.initials: EL
authors.lastname: Millan-Lagunas
authors.affiliation: UNESCO-IHE, Westvest 7, Delft 2611 AX, The Netherlands.
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopez-Vazquez
authors.affiliation: UNESCO-IHE, Westvest 7, Delft 2611 AX, The Netherlands.
authors.forename: Christine Maria
authors.initials: CM
authors.lastname: Hooijmans
authors.affiliation: Polytechnique Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, Québec, Canada H3C 3A7.
authors.forename: Yves
authors.initials: Y
authors.lastname: Comeau
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D052836:Heterotrophic Processes; D008962:Models, Theoretical; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*
chemical_list: D012722:Sewage; D062065:Wastewater