Viscous and filamentous bulking in activated sludge: Rheological and hydrodynamic modelling based on experimental data

V. Bakos, B. Gyarmati, P. Csizmadia, S. Till, L. Vachoud, P. Nagy Göde, G. M. Tardy, A. Szilágyi, A. Jobbágy, C. Wisniewski

Research output: Contribution to journalArticlepeer-review

13 Citations (SciVal)

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.

Original languageEnglish
Article number118155
JournalWater Research
Volume214
Early online date3 Feb 2022
DOIs
Publication statusPublished - 1 May 2022

Bibliographical note

Funding Information:
The cross-border cooperation was supported both by Hungarian National Research, Development and Innovation Office (TÉT-14-FR-1-2015-0033) and Campus France (PHC Balaton No.34474QA). Professional contribution of Michele Delalonde and the technical help of Emilie Ruiz (UMR QualiSud, University of Montpellier) is highly acknowledged. Additional support of the Higher Education Excellence Program of the Ministry of Human Capacities (EMMI) within the frame of both Biotechnology and Water Science and Disaster Prevention research areas of Budapest University of Technology and Economics (BME FIKP-BIO and FIKP-VIZ) is also highly appreciated. Authors acknowledge the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and the ÚNKP-19-4-BME-421, ÚNKP-20-5-BME-156, ÚNKP-21-5-BME New National Excellence Program of the Ministry of Human Capacities.

Funding Information:
The cross-border cooperation was supported both by Hungarian National Research, Development and Innovation Office (TÉT-14-FR-1-2015-0033) and Campus France (PHC Balaton No.34474QA). Professional contribution of Michele Delalonde and the technical help of Emilie Ruiz (UMR QualiSud, University of Montpellier) is highly acknowledged. Additional support of the Higher Education Excellence Program of the Ministry of Human Capacities (EMMI) within the frame of both Biotechnology and Water Science and Disaster Prevention research areas of Budapest University of Technology and Economics (BME FIKP-BIO and FIKP-VIZ) is also highly appreciated. Authors acknowledge the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and the ÚNKP-19-4-BME-421, ÚNKP-20-5-BME-156, ÚNKP-21-5-BME New National Excellence Program of the Ministry of Human Capacities.

Publisher Copyright:
© 2022

Keywords

  • Activated sludge
  • Computational fluid dynamics
  • Filamentous bulking
  • Hydrodynamics
  • Non-Newtonian flow
  • Viscous bulking

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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