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Bakos V, Gyarmati B, Csizmadia P, Till S, Vachoud L, Nagy Göde P, Tardy GM, Szilágyi A, Jobbágy A, Wisniewski C. Viscous and filamentous bulking in activated sludge: Rheological and hydrodynamic modelling based on experimental data. Water Res 2022; 214:118155. [PMID: 35184017 DOI: 10.1016/j.watres.2022.118155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 01/04/2022] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Although achieving good activated sludge settleability is a key requirement for meeting effluent quality criteria, wastewater treatment plants often face undesired floc structure changes. Filamentous bulking has widely been studied, however, viscous sludge formation much less investigated so far. Our main goal was to find relationship between sludge floc structure and related rheological properties, moreover, to estimate pressure loss in pipe networks through hydrodynamic modelling of the non-Newtonian flows in case of well settling (ideal-like), viscous and filamentous sludge. Severe viscous and filamentous kinds of bulking were generated separately in continuous-flow lab-scale systems initially seeded with the same reference (ideal-like) biomass and the entire evolution of viscous and filamentous bulking was monitored. The results suggested correlation between the rheological properties and the floc structure transformations, and showed the most appropriate fit for the Herschel-Bulkley model (vs. Power-law and Bingham). Validated computational fluid dynamics studies estimated the pipe pressure loss in a wide Reynolds number range for the initial well settling (reference) and the final viscous and filamentous sludge as well. A practical standard modelling protocol was developed for improving energy efficiency of sludge pumping in different floc structure scenarios.
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Affiliation(s)
- V Bakos
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary; Department of Chemical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - B Gyarmati
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - P Csizmadia
- Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - S Till
- Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - L Vachoud
- Qualisud, Université de Montpellier, CIRAD, Institut Agro, Avignon Université, Université de La Réunion, Montpellier, France
| | - P Nagy Göde
- DMRV Co. Ltd., Kodály Zoltán út 3., H-2600 Vác, Hungary
| | - G M Tardy
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - A Szilágyi
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - A Jobbágy
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - C Wisniewski
- Qualisud, Université de Montpellier, CIRAD, Institut Agro, Avignon Université, Université de La Réunion, Montpellier, France
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