title: Organic removal activity in biofilm and suspended biomass fractions of MBBR systems.
abstract: The moving bed biofilm reactor (MBBR) wastewater treatment process is usually designed based on the assumption that all activity in the process occurs in the biofilm on the MBBR carriers, although there is always some active biomass in the bulk liquid due to biofilm sloughing and, sometimes, free-growing bacteria. In this study the removal of organic matter is evaluated in laboratory-scale MBBR reactors under varying load, hydraulic retention time (HRT), oxygen concentration and volumetric filling degree of carriers in order to determine the heterotrophic activity in the different fractions of the MBBR biomass. The results showed that the heterotrophic conversions in an MBBR can show the same type of diffusion limited dependency on oxygen as nitrification, even for easily degradable substrates such as acetate. The contribution to the removal from the suspended biomass is shown to vary depending on HRT, as the amount of suspended solids changes. The developed method in this report is a useful tool for determining heterotrophic activity in the separate fractions of biomass in MBBRs.
authors.affiliation: AnoxKaldnes AB, Klosterängsvägen 11A, SE-226 47, Lund, Sweden E-mail: maria.piculell@anoxkaldnes.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Piculell
authors.affiliation: AnoxKaldnes AB, Klosterängsvägen 11A, SE-226 47, Lund, Sweden E-mail: maria.piculell@anoxkaldnes.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Welander
authors.affiliation: Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Jönsson
mesh_terms: D018441:Biofilms; D018533:Biomass; D014865:Waste Disposal, Fluid / Q000379:methods*