Heterogeneous diffusion in aerobic granular sludge

Lenno van den Berg, Catherine M. Kirkland, Joseph D. Seymour, Sarah L. Codd, Mark C.M. van Loosdrecht, Merle K. de Kreuk

Research output: Contribution to journalArticleScientificpeer-review

2 Downloads (Pure)

Abstract

Aerobic granular sludge (AGS) technology allows simultaneous nitrogen, phosphorus, and carbon removal in compact wastewater treatment processes. To operate, design, and model AGS reactors, it is essential to properly understand the diffusive transport within the granules. In this study, diffusive mass transfer within full-scale and lab-scale AGS was characterized with nuclear magnetic resonance (NMR) methods. Self-diffusion coefficients of water inside the granules were determined with pulsed-field gradient NMR, while the granule structure was visualized with NMR imaging. A reaction-diffusion granule-scale model was set up to evaluate the impact of heterogeneous diffusion on granule performance. The self-diffusion coefficient of water in AGS was ∼70% of the self-diffusion coefficient of free water. There was no significant difference between self-diffusion in AGS from full-scale treatment plants and from lab-scale reactors. The results of the model showed that diffusional heterogeneity did not lead to a major change of flux into the granule (<1%). This study shows that differences between granular sludges and heterogeneity within granules have little impact on the kinetic properties of AGS. Thus, a relatively simple approach is sufficient to describe mass transport by diffusion into the granules.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalBiotechnology and Bioengineering
DOIs
Publication statusE-pub ahead of print - 2020

Keywords

  • aerobic granular sludge
  • diffusion
  • granule structure
  • heterogeneity
  • NMR

Fingerprint Dive into the research topics of 'Heterogeneous diffusion in aerobic granular sludge'. Together they form a unique fingerprint.

  • Cite this