title: Role of plants in nitrogen and sulfur transformations in floating hydroponic root mats: A comparison of two helophytes.
abstract: Knowledge about the roles helophytes play in constructed wetlands (CWs) is limited, especially regarding their provision of organic rhizodeposits. Here, transformations of inorganic nitrogen and sulfur were monitored in a CW variety, floating hydroponic root mat (FHRM), treating synthetic wastewater containing low concentration of organic carbon. Two helophytes, Phragmites australis and Juncus effusus, were compared in duplicates. Striking differences were found between the FHRM of the two helophytes. Whereas ammonium was removed in all FHRMs to below detection level, total nitrogen of 1.15 ± 0.4 g m(-2) d(-1) was removed completely only in P. australis systems. The mats with J. effusus displayed effective nitrification but incomplete denitrification as 77% of the removed ammonium-nitrogen accumulated as nitrate. Furthermore, the P. australis treatment units showed on average 3 times higher sulfate-S removal rates (1.1 ± 0.45 g m(-2) d(-1)) than the systems planted with J. effusus (0.37 ± 0.29 g m(-2) d(-1)). Since the influent organic carbon was below the stoichiometric requirement for the observed N and S transformation processes, helophytes' organic rhizodeposits apparently contributed to these transformations, while P. australis provided about 6 times higher bioavailable organic rhizodeposits than J. effusus.
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig, Germany.
authors.forename: Rania A B
authors.initials: RAB
authors.lastname: Saad
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kuschk
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig, Germany.
authors.forename: Arndt
authors.initials: A
authors.lastname: Wiessner
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Kappelmeyer
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig, Germany. Electronic address: jochen.mueller@ufz.de.
authors.forename: Jochen A
authors.initials: JA
authors.lastname: Müller
authors.affiliation: Otto-von-Guericke-University Magdeburg, FVST Chair Environmental Technology, Universitätsplatz 2, D-39106 Magdeburg, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Köser
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D058440:Denitrification; D005858:Germany; D018527:Hydroponics / Q000379:methods*; D009566:Nitrates / Q000378:metabolism; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism* / Q000502:physiology; D013045:Species Specificity; D013455:Sulfur / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry; D053833:Wetlands
chemical_list: D064751:Ammonium Compounds; D002244:Carbon; D009566:Nitrates; D009584:Nitrogen; D013455:Sulfur; D062065:Wastewater
keywords: Constructed wetlands; Dissimilatory sulfate reduction; Floating hydroponic root mat; Juncus effusus; Nitrogen removal; Phragmites australis