A multi-component model for granular activated carbon filters combining biofilm and adsorption kinetics. (1st June 2021)

• Record Type: Journal Article
• Authors: Acevedo Alonso, Vanessa; Kaiser, Tobias; Babist, Roman; Fundneider, Thomas; Lackner, Susanne
• Is Part Of: Water research. Volume 197(2021)
• Publication Date: 2021-06-01
• Subjects: Adsorption -- Advanced wastewater treatment -- Biodegradation -- Biofilm -- Micropollutants; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2021.117079
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: DOC is fractionated according to its adsorbability and biodegradability Multi-component adsorption and biofilm kinetics are combined for the first time DOC breakthrough curves are predicted for bGAC-filters treating WWTP effluents A lumped variable for the adsorbed components (qT ) is successfully implemented The model reproduces the EBCT effect on the adsorptive and biological DOC removal Abstract: Along with the rise of biological active granular activated carbon (bGAC) filtration as advanced treatment technology for wastewater treatment plant (WWTP) effluents, the mathematical representation of such systems is gaining increasing importance. This work introduces a model that describes the performance of bGAC-filters for Dissolved Organic Carbon (DOC) removal from a WWTP effluent. The DOC removal within bGAC-filters is accomplished by two mechanisms: adsorptive removal and biological transformation. An appropriate representation of the adsorptive removal requires the DOC to be divided into fictive fractions according to its adsorbability. Likewise, a further DOC classification according to its biodegradability is necessary. Modeling a bGAC-filter then becomes a multi-component adsorption problem, with the simultaneous occurrence of DOC degradation within a biofilm. For dealing with this modeling task, this work integrated the Ideal Adsorbed Solution (IAS) theory into a traditional biofilm model compatible with the Activated Sludge Model (ASM) Framework. For the description of the adsorption dynamics, a Freundlich isotherm for the equilibrium and a pseudo first order model for the kinetics were selected. The biofilm consisted of heterotrophic bacteria able to oxidize DOC using oxygen as electron acceptor. The correctness of the model was evaluated using experimental data from a pilot plant. The predicted DOC breakthrough curve satisfactorily fitted the experimental measurements for empty bed contact times (EBCT) of 6, 12, 24 and 33 min. Moreover, the model predicted the relationship between EBCT, DOC removal and bGAC-filter lifespan. The developed model is the first that combines multi-component adsorption and biofilm kinetics in a wastewater treatment context. Graphical abstract: Image, graphical abstract