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Influence of NOM concentration on parameter sensitivity of a mechanistic ozone decomposition model

Wim Audenaert UGent, Mathieu Vandevelde, Stijn Van Hulle UGent and Ingmar Nopens UGent (2011) Natural Organic Matter, 4th IWA specialist conference, Proceedings.
abstract
Aqueous ozone decomposition proceeds through a complex chain mechanism of radical reactions. When natural organic matter (NOM) is present, the system becomes even more complex and often (semi-)empirical modelling approaches are used to describe ozonation of water and wastewater systems. Mechanistic models, however, can be of great value to gain knowledge in the chemical pathways of ozonation and advanced oxidation processes (AOPs) in view of engineering applications. However, the numerous model parameters and model complexity often restrict their applicability. Model simplification is then an option to cure these drawbacks. In this study, sensitivity analyses (SAs) were used to determine the most important elementary reactions from the complex kinetic model. Additionally, SAs were used to understand the reaction mechanism. It was demonstrated that only seven of the twenty-eight first and second order rate constants showed to impact ozone and hydroxyl radical (HO•) concentrations. Processes involving HO• scavenging by inorganic carbon were of minor importance. Mass-transfer related parameters were of major importance in all cases. Hence, it is of extreme importance that these parameters are determined with high accuracy. It was shown that the aqueous ozone concentration is extremely sensitive to parameters involving NOM at very low scavenger concentrations implying that impurities should always be considered in AOP models, even in ultrapure water systems. Uncertainty analysis showed that especially the HO• concentration is susceptible to variations in influent composition. The uncertainty regarding this species significantly reduced with increasing levels of scavengers and especially NOM. It was demonstrated that simplification of the elementary radical scheme should be considered. On the other hand, a model extension with regard to reactions involving NOM should be performed in order to improve the applicability of future wastewater ozonation models.
Please use this url to cite or link to this publication:
author
organization
year
type
conference
publication status
published
subject
keyword
natural organic matter, sensitivity analysis, ozone kinetics, ozone decomposition
in
Natural Organic Matter, 4th IWA specialist conference, Proceedings
pages
21 pages
publisher
International Water Association (IWA)
conference name
4th IWA Specialist conference on Natural Organic Matter
conference location
Irvine, CA, USA
conference start
2011-07-27
conference end
2011-07-29
language
English
UGent publication?
yes
classification
C1
copyright statement
I have transferred the copyright for this publication to the publisher
id
1910931
handle
http://hdl.handle.net/1854/LU-1910931
date created
2011-09-28 16:09:32
date last changed
2011-09-29 09:00:33
@inproceedings{1910931,
  abstract     = {Aqueous ozone decomposition proceeds through a complex chain mechanism of radical reactions. When natural organic matter (NOM) is present, the system becomes even more complex and often (semi-)empirical modelling approaches are used to describe ozonation of water and wastewater systems. Mechanistic models, however, can be of great value to gain knowledge in the chemical pathways of ozonation and advanced oxidation processes (AOPs) in view of engineering applications. However, the numerous model parameters and model complexity often restrict their applicability. Model simplification is then an option to cure these drawbacks. In this study, sensitivity analyses (SAs) were used to determine the most important elementary reactions from the complex kinetic model. Additionally, SAs were used to understand the reaction mechanism. It was demonstrated that only seven of the twenty-eight first and second order rate constants showed to impact ozone and hydroxyl radical (HO{\textbullet}) concentrations. Processes involving HO{\textbullet} scavenging by inorganic carbon were of minor importance. Mass-transfer related parameters were of major importance in all cases. Hence, it is of extreme importance that these parameters are determined with high accuracy. It was shown that the aqueous ozone concentration is extremely sensitive to parameters involving NOM at very low scavenger concentrations implying that impurities should always be considered in AOP models, even in ultrapure water systems. Uncertainty analysis showed that especially the HO{\textbullet} concentration is susceptible to variations in influent composition. The uncertainty regarding this species significantly reduced with increasing levels of scavengers and especially NOM. It was demonstrated that simplification of the elementary radical scheme should be considered. On the other hand, a model extension with regard to reactions involving NOM should be performed in order to improve the applicability of future wastewater ozonation models.},
  author       = {Audenaert, Wim and Vandevelde, Mathieu and Van Hulle, Stijn and Nopens, Ingmar},
  booktitle    = {Natural Organic Matter, 4th IWA specialist conference, Proceedings},
  keyword      = {natural organic matter,sensitivity analysis,ozone kinetics,ozone decomposition},
  language     = {eng},
  location     = {Irvine, CA, USA},
  pages        = {21},
  publisher    = {International Water Association (IWA)},
  title        = {Influence of NOM concentration on parameter sensitivity of a mechanistic ozone decomposition model},
  year         = {2011},
}

Chicago
Audenaert, Wim, Mathieu Vandevelde, Stijn Van Hulle, and Ingmar Nopens. 2011. “Influence of NOM Concentration on Parameter Sensitivity of a Mechanistic Ozone Decomposition Model.” In Natural Organic Matter, 4th IWA Specialist Conference, Proceedings. International Water Association (IWA).
APA
Audenaert, W., Vandevelde, M., Van Hulle, S., & Nopens, I. (2011). Influence of NOM concentration on parameter sensitivity of a mechanistic ozone decomposition model. Natural Organic Matter, 4th IWA specialist conference, Proceedings. Presented at the 4th IWA Specialist conference on Natural Organic Matter, International Water Association (IWA).
Vancouver
1.
Audenaert W, Vandevelde M, Van Hulle S, Nopens I. Influence of NOM concentration on parameter sensitivity of a mechanistic ozone decomposition model. Natural Organic Matter, 4th IWA specialist conference, Proceedings. International Water Association (IWA); 2011.
MLA
Audenaert, Wim, Mathieu Vandevelde, Stijn Van Hulle, et al. “Influence of NOM Concentration on Parameter Sensitivity of a Mechanistic Ozone Decomposition Model.” Natural Organic Matter, 4th IWA Specialist Conference, Proceedings. International Water Association (IWA), 2011. Print.