Title
Oxygen transfer efficiency in an aerobic granular sludge reactor: Dynamics and influencing factors of alpha
Author
Strubbe, Laurence (Universiteit Gent)
van Dijk, E.J.H. (TU Delft BT/Environmental Biotechnology; Royal HaskoningDHV) 
Deenekamp, Pascalle J.M. (Royal HaskoningDHV)
van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)
Volcke, Eveline I.P. (Universiteit Gent)
Date
2023
Abstract
In the pursuit of reducing carbon footprint and in view of increasing energy prices, energy efficiency is more important than ever before. Batch-wise operated aerobic granular sludge reactors consume up to 50% less energy compared to conventional activated sludge systems because pumping energy is reduced and mixing equipment is not needed. Further energy reduction efforts should therefore target aeration energy requirements. The alpha factor is an important factor influencing the oxygen transfer efficiency, however the dynamic behaviour of alpha has hardly been investigated in general and never for an aerobic granular sludge reactor. This study showed that alpha increases during the aeration phase of a cycle due to the influence of different process parameters. Through a data analysis study of 175 batch cycles of the Prototype Nereda® installation in Utrecht over the summer and winter period of 2020–2021, the exchange ratio and temperature were identified as the main influencing factors on the rate of increase of alpha in a batch cycle. A higher exchange ratio was related to a slower increase in alpha over the aeration phase, while a higher temperature was related to a faster increase in alpha. Moreover, alpha was characterized by a same minimal value at the beginning of every aeration phase, which could be explained by the adsorption of soluble biodegradable organic carbon described by a Langmuir adsorption model. Two mathematical models, a decreasing exponential and a first order model, were set up to unravel the dynamic behaviour of alpha. Both models were discussed in view of their practical implications for the design and performance optimization of aerobic granular sludge reactors and other batch-wise operated aerobic wastewater treatment systems.
Subject
Aeration
Aerobic granular sludge (AGS)
Alpha factor
Batch-wise operation
Oxygen transfer efficiency
Wastewater treatment
To reference this document use:
http://resolver.tudelft.nl/uuid:b86dc8ba-f6a2-45ca-94ef-cc236678a1cf
DOI
https://doi.org/10.1016/j.cej.2022.139548
Embargo date
2023-07-01
ISSN
1385-8947
Source
Chemical Engineering Journal, 452
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2023 Laurence Strubbe, E.J.H. van Dijk, Pascalle J.M. Deenekamp, Mark C.M. van Loosdrecht, Eveline I.P. Volcke