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Modelling a Lab-Scale Continuous Flow Aerobic Granular Sludge Reactor: Optimisation Pathways for Scale-Up

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Bibliographic Details
Title: Modelling a Lab-Scale Continuous Flow Aerobic Granular Sludge Reactor: Optimisation Pathways for Scale-Up
Authors: Melissa Siney, Reza Salehi, Mohamed G. Hassan, Rania Hamza, Ihab M. T. A. Shigidi
Source: Water ; Volume 17 ; Issue 14 ; Pages: 2131
Publisher Information: Multidisciplinary Digital Publishing Institute
Publication Year: 2025
Collection: MDPI Open Access Publishing
Subject Terms: Aerobic Granular Sludge (AGS), continuous flow reactor, Computational Fluid Dynamics (CFD), Monod kinetics, wastewater treatment, biochemical modelling, reactor scale-up, python simulation, mass transfer, Oxygen Uptake Rate (OUR)
Subject Geographic: agris
Description: Wastewater treatment plants (WWTPs) face increasing pressure to handle higher volumes of water due to climate change causing storm surges, which current infrastructure cannot handle. Aerobic granular sludge (AGS) is a promising alternative to activated sludge systems due to their improved settleability property, lowering the land footprint and improving efficiency. This research investigates the optimisation of a lab-scale sequencing batch reactor (SBR) into a continuous flow reactor through mathematical modelling, sensitivity analysis, and a computational fluid dynamic model. This is all applied for the future goal of scaling up the model designed to a full-scale continuous flow reactor. The mathematical model developed analyses microbial kinetics, COD degradation, and mixing flows using Reynolds and Froude numbers. To perform a sensitivity analysis, a Python code was developed to investigate the stability when influent concentrations and flow rates vary. Finally, CFD simulations on ANSYS Fluent evaluated the mixing within the reactor. An 82% COD removal efficiency was derived from the model and validated against the SBR data and other configurations. The sensitivity analysis highlighted the reactor’s inefficiency in handling high-concentration influents and fast flow rates. CFD simulations revealed good mixing within the reactor; however, they did show issues where biomass washout would be highly likely if applied in continuous flow operation. All of these results were taken under deep consideration to provide a new reactor configuration to be studied that may resolve all these downfalls.
Document Type: text
File Description: application/pdf
Language: English
Relation: Wastewater Treatment and Reuse; https://dx.doi.org/10.3390/w17142131
DOI: 10.3390/w17142131
Availability: https://doi.org/10.3390/w17142131
Rights: https://creativecommons.org/licenses/by/4.0/
Accession Number: edsbas.70707D13
Database: BASE
Description
Abstract:Wastewater treatment plants (WWTPs) face increasing pressure to handle higher volumes of water due to climate change causing storm surges, which current infrastructure cannot handle. Aerobic granular sludge (AGS) is a promising alternative to activated sludge systems due to their improved settleability property, lowering the land footprint and improving efficiency. This research investigates the optimisation of a lab-scale sequencing batch reactor (SBR) into a continuous flow reactor through mathematical modelling, sensitivity analysis, and a computational fluid dynamic model. This is all applied for the future goal of scaling up the model designed to a full-scale continuous flow reactor. The mathematical model developed analyses microbial kinetics, COD degradation, and mixing flows using Reynolds and Froude numbers. To perform a sensitivity analysis, a Python code was developed to investigate the stability when influent concentrations and flow rates vary. Finally, CFD simulations on ANSYS Fluent evaluated the mixing within the reactor. An 82% COD removal efficiency was derived from the model and validated against the SBR data and other configurations. The sensitivity analysis highlighted the reactor’s inefficiency in handling high-concentration influents and fast flow rates. CFD simulations revealed good mixing within the reactor; however, they did show issues where biomass washout would be highly likely if applied in continuous flow operation. All of these results were taken under deep consideration to provide a new reactor configuration to be studied that may resolve all these downfalls.
DOI:10.3390/w17142131