Dynamic modeling of manganese removal in a pyrolusite fluidized bed contactor. (1st May 2019)

• Record Type: Journal Article
• Authors: Dashtban Kenari, Seyedeh Laleh; Shabanian, Jaber; Barbeau, Benoit
• Is Part Of: Water research. Volume 154(2019)
• Page Start: 125
• Page End: 135
• Publication Date: 2019-05-01
• Subjects: Drinking water -- Manganese removal -- Pyrolusite fluidized bed contactor -- Modeling -- Breakthrough; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2019.01.046
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: A novel pyrolusite fluidized bed (PFB) contactor, which we recently developed for dissolved manganese (Mn(II)) removal through surface adsorption and subsequent oxidation by free chlorine, was modeled in this study. The hydrodynamic behavior of the filter media and water in the fluidized bed was described by the axial dispersion model. The model incorporated the effects of axial mixing in the liquid and solid phases, mass transfer resistance in a laminar fluid boundary layer surrounding a media grain, and a second order oxidation rate expression. The experimental data from lab-scale and field pilot-scale contactors was adopted for the model development and its validation. For the former, the data was employed to estimate the oxidation rate constant, the mass transfer coefficient, and the axial solid phase dispersion coefficient for the model. The model simulations matched the experimental data with less than 20% error across a wide range of Mn(II) and free chlorine concentrations and hydraulic loading rates that might be encountered in a drinking water treatment plant. The sensitivity analysis showed that the time to breakthrough is most sensitive to the adsorption isotherm constants and the oxidation rate constant. These observations indicate that the alluded parameters mainly control the performance of the PFB contactor as well as the process stability. Finally, a sample application of the model to acquire operational inputs was illustrated by analyzing the effect of free chlorine concentration on Mn(II) removal performance and breakthrough time within a PFB contactor. Graphical abstract: Image 1 Highlights: A dynamic mechanistic model for manganese removal within a pyrolusite fluidized bed. Model validation with lab and field pilot-scale experimental data. Breakthrough most sensitive to the Freundlich isotherm and oxidation rate constants. Model application under various conditions.