Short and long term continuous hydroxylamine feeding in a granular sludge partial nitritation reactor

Aina Soler-Jofra; Lisbeth Schmidtchen; Lluc Olmo; Mark C M van Loosdrecht; Julio Pérez

doi:10.1016/j.watres.2021.117945

Short and long term continuous hydroxylamine feeding in a granular sludge partial nitritation reactor

Water Res. 2022 Feb 1:209:117945. doi: 10.1016/j.watres.2021.117945. Epub 2021 Dec 7.

Authors

Aina Soler-Jofra¹, Lisbeth Schmidtchen¹, Lluc Olmo², Mark C M van Loosdrecht³, Julio Pérez²

Affiliations

¹ Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands.
² Department of Chemical, Biological and Environmental Engineering, Universitat Autonoma de Barcelona, Cerdanyola del Valles, Spain.
³ Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands. Electronic address: M.C.M.vanLoosdrecht@tudelft.nl.

PMID: 34936973
DOI: 10.1016/j.watres.2021.117945

Abstract

Hydroxylamine is a nitrogen intermediate of ammonium oxidizing bacteria (AOB) that can transiently accumulate during nitrification. The impact of hydroxylamine on aerobic ammonium oxidations is still obscure. In the present study the short and long term impact of hydroxylamine on partial nitritation granular sludge was investigated. Dissolved oxygen was the governing factor determining the hydroxylamine impact in short term studies with continuous hydroxylamine feeding. Continuous short term hydroxylamine feeding together with low dissolved oxygen resulted in higher hydroxylamine accumulation, higher N₂O production and decreased or maintained ammonium consumption. Instead, high dissolved oxygen reduced hydroxylamine accumulation and N₂O production and increased ammonium consumption. Long term continuous hydroxylamine feeding reduced ammonium consumption rate while the constant nitrite production rate indicated that dosed hydroxylamine was mainly transformed to nitrite. This indicates that hydroxylamine was preferred over ammonium as substrate. Nitrosomonas sp. was shown to be predominant during continuous hydroxylamine feeding while the side community shifted.

Keywords: Ammonium; Ammonium oxidizing bacteria; Hydroxylamine; Nitrite.