Nitrous Oxide Production in a Granule-based Partial Nitritation Reactor: A Model-based Evaluation.

ABSTRACT: Sustainable wastewater treatment has been attracting increasing attentions over the past decades. However, the production of nitrous oxide (N₂O), a potent GHG, from the energy-efficient granule-based autotrophic nitrogen removal is largely unknown. This study applied a previously established N₂O model, which incorporated two N₂O production pathways by ammonia-oxidizing bacteria (AOB) (AOB denitrification and the hydroxylamine (NH₂OH) oxidation). The two-pathway model was used to describe N₂O production from a granule-based partial nitritation (PN) reactor and provide insights into the N₂O distribution inside granules. The model was evaluated by comparing simulation results with N₂O monitoring profiles as well as isotopic measurement data from the PN reactor. The model demonstrated its good predictive ability against N₂O dynamics and provided useful information about the shift of N₂O production pathways inside granules for the first time. The simulation results indicated that the increase of oxygen concentration and granule size would significantly enhance N₂O production. The results further revealed a linear relationship between N₂O production and ammonia oxidation rate (AOR) (R²?=?0.99) under the conditions of varying oxygen levels and granule diameters, suggesting that bulk oxygen and granule size may exert an indirect effect on N₂O production by causing a change in AOR.

SUBMITTER: Peng L 

PROVIDER: S-EPMC5377315 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature