Publication
Title
High-resolution mapping and modeling of anammox recovery from recurrent oxygen exposure
Author
Abstract
Oxygen inhibits anammox, a bioconversion executed by anoxic ammonium oxidizing bacteria (AnAOB). Nonetheless, oxygen is mostly found in the proximity of AnAOB in nitrogen removal applications, being a substrate for nitritation. The experiments performed to date were mostly limited to batch activity tests where AnAOB activity is estimated during oxygen exposure. However, little attention has been paid to the recovery and reversibility of activity following aerobic conditions, of direct relevance for bioreactor operation. In this work, anoxic and autotrophic reactor cultivation at 20 degrees C yielded an enriched microbial community in AnAOB, consisting for 75% of a member of the genus Brocadia. High-resolution kinetic data were obtained with online ammonium measurements and further processed with a newly developed Python data pipeline. The experimentally obtained AnAOB response showed complete inhibition until micro-aerobic conditions were reached again (<0.02 mg O-2 L-1). After oxygen inhibition, AnAOB recovered gradually, with recovery times of 5-37 h to reach a steady-state activity, dependent on the perceived inhibition. The recovery immediately after inhibition was lowest when exposed to higher oxygen concentrations (range: 0.5-8 mg O-2 L-1) with long contact times (range: 9-24 h). The experimental data did not fit well with a conventional 'instant recovery' Monod-type inhibition model. Yet, the fit greatly improved by incorporating a dynamic growth rate formula accurately describing gradual activity recovery. With the upgraded model, long-term kinetic simulations for partial nitritation/anammox (PN/A) with intermittent aeration showed a decrease in growth rate compared to the instant recovery mode. These results indicate that recovery of AnAOB after oxygen exposure was previously overlooked. It is recommended to account for this effect in the intensification of partial nitritation/anammox. (C) 2018 Elsevier Ltd. All rights reserved.
Language
English
Source (journal)
Water research / International Association on Water Pollution Research. - Oxford, 1967, currens
Water research / International Association on Water Pollution Research. - Oxford, 1967, currens
Publication
Oxford : 2018
ISSN
0043-1354
Volume/pages
144 (2018) , p. 522-531
ISI
000447569300051
Pubmed ID
30077912
Full text (Publisher's DOI)
Full text (open access)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 30.08.2018
Last edited 20.09.2021
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