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International Journal of Chemical Engineering
Volume 2010, Article ID 412734, 6 pages
http://dx.doi.org/10.1155/2010/412734
Research Article

Modeling the Effect of Plants and Peat on Evapotranspiration in Constructed Wetlands

1Institut de Recherche en Biologie végétale, Université de Montréal, 4101 Sherbrooke St. East, Montréal, QC, Canada H1X 2B2
2Department of Civil, Geological and Mining Engineering, École Polytechnique, Montréal, QC, Canada H3C 3A7
3Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement, Université de Savoie, Campus Scientifique, 73 376 Le Bourget du Lac Cedex, France

Received 15 January 2010; Accepted 17 April 2010

Academic Editor: Evans M. Nkhalambayausi-Chirwa

Copyright © 2010 Florent Chazarenc et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Evapotranspiration (ET) in constructed wetlands (CWs) represents a major factor affecting hydrodynamics and treatment performances. The presence of high ET was shown to improve global treatment performances, however ET is affected by a wide range of parameters including plant development and CWs age. Our study aimed at modelling the effect of plants and peat on ET in CWs; since we hypothesized peat could behave like the presence of accumulated organic matter in old CWs. Treatment performances, hydraulic behaviour, and ET rates were measured in eight 1 m2 CWs mesocosm (1 unplanted, 1 unplanted with peat, 2 planted with Phragmites australis, 2 planted with Typha latifolia and 2 planted with Phragmites australis with peat). Two models were built using first order kinetics to simulate COD and TKN removal with ET as an input. The effect of peat was positive on ET and was related to the better growth conditions it offered to macrophytes. Removal efficiency in pilot units with larger ET was higher for TKN. On average, results show for COD a k20 value of 0.88 d1 and 0.36 d1 for TKN. We hypothesized that the main effect of ET was to concentrate effluent, thus enhancing degradation rates.