Print Email Facebook Twitter How to measure diffusion coefficients in biofilms Title How to measure diffusion coefficients in biofilms: A critical analysis Author van den Berg, L. (TU Delft Sanitary Engineering) van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology) de Kreuk, M.K. (TU Delft Sanitary Engineering) Date 2020 Abstract Biofilm and granular sludge processes depend on diffusion of substrates. Despite their importance for the kinetic description of biofilm reactors, biofilm diffusion coefficients reported in literature vary greatly. The aim of this simulation study was to determine to what extent the methods that are used to measure diffusion coefficients contribute to the reported variability. Granular sludge was used as a case study. Six common methods were selected, based on mass balances and microelectrodes. A Monte Carlo simulation was carried out to determine the theoretical precision of each method, considering the uncertainty of various experimental parameters. A model-based simulation of a diffusion experiment was used to determine the theoretical accuracy as a result of six sources of error: solute sorption, biomass deactivation, mass transfer boundary layer, granule roughness, granule shape, and granule size distribution. Based on the Monte Carlo analysis, the relative standard deviation of the different methods ranged from 5% to 61%. In a theoretical experiment, the six error sources led to an 37% underestimation of the diffusion coefficient. This highlights that diffusion coefficients cannot be determined accurately with existing experimental methods. At the same time, the need for measuring precise diffusion coefficients as input value for biofilm modeling can be questioned, since the output of biofilm models has a limited sensitivity toward the diffusion coefficient. Subject biofilmdiffusion coefficienterror analysisgranular sludgewastewater treatment To reference this document use: http://resolver.tudelft.nl/uuid:3272859b-3247-43fc-931b-621167b0ae08 DOI https://doi.org/10.1002/bit.27650 ISSN 0006-3592 Source Biotechnology and Bioengineering, 118 (2021) (3), 1273-1285 Part of collection Institutional Repository Document type journal article Rights © 2020 L. van den Berg, Mark C.M. van Loosdrecht, M.K. de Kreuk Files PDF bit.27650.pdf 1.11 MB Close viewer /islandora/object/uuid:3272859b-3247-43fc-931b-621167b0ae08/datastream/OBJ/view