Coupling anammox and heterotrophic denitrification activity at mainstream conditions in a single reactor unit
Juan Díaz, Xènia (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Pérez Cañestro, Julio (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Carrera, Julian (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Date:	2022
Abstract:	Mainstream partial nitritation/anammox (PN/AMX) has attracted large attention in the last decade. Two-stage configurations have been pointed out as an appealing technology for the application of the PN/AMX process at mainstream conditions. However, the process requires of an efficiency improvement by designing a new technology to remove the nitrate produced by anammox bacteria. A new reactor configuration was developed by coupling anammox to heterotrophic denitrification in a single reactor unit while avoiding competition between both processes. The addition of acetate as an external C-source allowed the removal of nitrate by heterotrophic microorganisms without hampering the anammox process by maintaining high nitrogen removal rates (0. 16 ± 0. 03 g N L-1 d-1) and nitrogen removal efficiencies (91 ± 8 %) (on average from acetate addition periods). Further, a proper organic load management showed to be effective to face the drawbacks derived from previous mainstream treatment stages (i. e. undesired nitrate production), without compromising effluent COD concentrations. By withdrawing samples along the sludge bed, nitrogen compounds and COD concentrations were determined at different reactor heights. This set of experimental data demonstrated that the combination of anammox and heterotrophic denitrification in a single reactor unit was possible as anammox activity dominated within bottom sludge bed sections, while heterotrophic denitrification occurred within middle and upper sludge sections. Microbial diversity results of 16S rRNA gene-targeted sequencing analyses confirmed that anammox and heterotrophic denitrifiers communities occupied two differentiated sludge bed sections along the reactor being dominated by Candidatus Brocadia (30 %) and Thauera (33 to 46 %), respectively. When heterotrophic denitrification occurred, the average N2O emissions with COD addition was ca. 50 % lower than that in periods without COD addition.
Grants:	Agencia Estatal de Investigación CTQ2017-82404-R
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Mainstream anammox ; Heterotrophic denitrification ; Organic carbon ; Cooperation network ; Single reactor unit ; Effluent quality
Published in:	Chemical engineering journal, Vol. 431, Issue 2 (March 2022) , art. 134087, ISSN 1873-3212

DOI: 10.1016/j.cej.2021.134087

11 p, 1.6 MB

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