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Influence of carbon to nitrogen ratio on nitrous oxide emission in an Integrated Fixed Film Activated Sludge Membrane BioReactor plant.

Authors :
Mannina, Giorgio
Ekama, George A.
Capodici, Marco
Cosenza, Alida
Di Trapani, Daniele
Ødegaard, Hallvard
Van Loosdrecht, Mark M.c.
Source :
Journal of Cleaner Production. Mar2018, Vol. 176, p1078-1090. 13p.
Publication Year :
2018

Abstract

In this study a University of Cape Town (UCT) Integrated Fixed Film Activated Sludge (IFAS) Membrane BioReactor (MBR) wastewater treatment plant was monitored in terms of nitrous oxide (N 2 O) emissions. The short term effect on the N 2 O emission due to the influent carbon-to-nitrogen (C/N) ratio variation (C/N ratios of 2, 5 and 10 gCOD/gN) was evaluated. Since in a previous study, the effect of the C/N ratio was studied in the same system without biofilm (UCT-MBR configuration) the main aim here was to investigate the role of biofilms on N 2 O emissions. Under all the investigated C/N ratios, the N 2 O fluxes and the average emission factors were lower than that of previous studies with no biofilm presence. The total average N 2 O emission was 0.5% of the influent nitrogen with biofilm (IFAS system) and 3.5% without biofilm. This result emphasizes the potential role of the biofilms in attenuating the N 2 O emissions especially in the case of stress conditions (i.e., low C/N influent ratios). An increase of N 2 O flux from the anoxic reactor (till 28 mgN 2 O m −2 h −1 ) occurred at the lowest influent C/N tested (2 gCOD/gN - phase III). At C/N equal to 2 gCOD/gN the anoxic reactor was the main source of N 2 O, contributing 45% of all produced N 2 O. This result was attributed to an incomplete denitrification caused by a lack of organic carbon and a slight increase of dissolved oxygen concentration. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09596526
Volume :
176
Database :
Academic Search Index
Journal :
Journal of Cleaner Production
Publication Type :
Academic Journal
Accession number :
127238029
Full Text :
https://doi.org/10.1016/j.jclepro.2017.11.222