Kinetics of hexavalent chromium reduction in constructed wetland mesocosms

CIM Journal, Vol. 5, No. 4, 2014

A. Rodriguez-Prado
Independent Consultant, Saskatoon, Saskatchewan, Canada
R. L. Legge
Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
W. C. Lennox
Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada
P. Kuschk
Department of Environmental Biotechnology,
Helmholtz Centre for Environmental Research, Leipzig, Germany
Abstract Using constructed wetlands to chemically reduce hexavalent chromium Cr(VI) to Cr(III) from industrial and mining wastewater has proven to be feasible and efficient. Applying first-order kinetics to describe the process is simple, but in some cases a more accurate model is required to reflect the process. This paper studies the feasibility of using non–first-order kinetics to describe the reduction process. Results indicate that half- and second-order kinetics adequately described Cr(VI) reduction in laboratory wetland mesocosms. The organic carbon content played a relevant role, whether it was built up by plant growth or spiked into the feed water.
Keywords: Constructed wetlands, Hexavalent chromium (Cr(VI)) reduction, Reduction kinetics, Wastewater treatment, Acid mine drainage
Résumé Les étudiants, même ceux qui ont de fortes connaissances mathématiques, ont souvent de la difficulté à comprendre les concepts de la géostatistique. L’un des principaux problèmes est la relation entre la variation des valeurs des paramètres dans l’espace ou le temps et le semi-variogramme expérimental calculé. Un autre défi est de différencier entre les semi-variogrammes directionnels et omnidirectionnels et leur interprétation. Des outils interactifs ont donc été développés; ils sont basés sur le logiciel libre R dans le domaine public. L’utilisation de ces outils interactifs est limitée à des situations éducatives (c.-à-d. pour visualiser les concepts de base). Les modules interactifs sont disponibles au : www.bwk.kuleuven.be/geostatistics.
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Publication: CIM Journal
Issue: 4
Volume: 5
Year: 2014
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Year: 2014
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Summary: RISKGATE is an interactive online risk management system that compiles and presents current practices from a diverse range of Australian coal mining experts. The system is designed to assist the industry in implementing continual improvement in management of major unwanted events, thus maximizing health and safety performance. This paper presents an overview of the comprehensive body of knowledge developed for management of unwanted strata incidents and explosions in the underground environme...
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B. Hebblewhite
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Issue: 4
Volume: 5
Year: 2014
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