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Title (Primary) Dynamics of arsenic species in laboratory-scale horizontal subsurface-flow constructed wetlands treating an artificial wastewater
Author Rahman, K.Z.; Wießner, A.; Kuschk, P.; Mattusch, J.; Kästner, M.; Müller, R.A.;
Journal Engineering in Life Sciences
Year 2008
Department UBT; ANA; UBZ;
Volume 8
Issue 6
Language englisch;
Keywords Arsenic removal; Artificial wastewater; Biotransformation; Laboratory-scale constructed wetlands
Abstract Knowledge regarding the dynamics of arsenic species and their interactions under gradient redox conditions in treatment wetlands is still insufficient. The aim of this investigation was to gain more information on the biotransformation of As and the dynamics of As species in horizontal subsurface-flow constructed wetlands. Experiments were carried out in laboratory-scale wetland systems, two planted with Juncus effusus and one unplanted, using an As-containing artificial wastewater under defined organic C- and SO42--loading conditions. Immobilization of As was found in all systems under conditions of limited C, mainly due to adsorption and/or co-precipitation. The removal efficiencies were substantially higher in the planted systems (60-70 %) as compared to the unplanted system (37 % on average). Immobilization under the conditions mentioned above appeared to decrease over time in all systems. At the beginning, the dosage of organic carbon immediately caused intensive microbial dissimilatory sulfate reduction in all systems (in the range of 85-95 %) and highly efficient removal of total arsenic (81-96 % on average). Later on, in this operation period, the intensity of sulfate reduction and simultaneous removal of As decreased, particularly in the planted wetlands (ranging from 30-46 %). One reason could be the re-oxidation of reduced compounds due to oxygenation of the rhizosphere by the emergent wetland plants (helophytes). A significant amount of reduced As [As(III)] was found in the planted systems (> 75 % of total As) during the period of efficient microbial sulfate reduction, compared to the unplanted system (> 25 % of total As). The immobilization of arsenic was found to behave more stably in the planted beds than in the unplanted bed. Both systems (planted and unplanted) were suitable to treat wastewater containing As, particularly under sulfate reducing conditions. The unplanted system seemed to be more efficient regarding the immobilization of As, but the planted systems showed a better stability of immobilized As.
ID 1332
Persistent UFZ Identifier http://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=1332
Rahman, K.Z., Wießner, A., Kuschk, P., Mattusch, J., Kästner, M., Müller, R.A. (2008):
Dynamics of arsenic species in laboratory-scale horizontal subsurface-flow constructed wetlands treating an artificial wastewater
Eng. Life Sci. 8 (6), 603 - 611