title: Nitrogen transforming bacteria within a full-scale partially saturated vertical subsurface flow constructed wetland treating urban wastewater.
abstract: The aim of this study was to characterize the nitrogen transforming bacterial communities within a partially saturated vertical subsurface flow constructed wetland (VF) treating urban wastewater in southern Brazil. The VF had a surface area of 3144m2, and was divided into four wetland cells, out of which two were operated while the other two rested, alternating cycles of 30days. The nitrifying and denitrifying bacterial communities were characterized in wetland cell 3 (764m2surface area) over a period of 12months by using the FISH technique. Samples were collected monthly (from Feb 2014 to Feb 2015) from different layers within the vertical profile, during operation and rest periods, comprising a total of 6 sampling campaigns while the cell was in operation and another 6 when the cell was at rest. This wetland cell operated with an average organic loading rate (OLR) of 4gCODm-2d-1and a hydraulic loading rate of 24.5mmd-1. The rest periods of the wetland cell presented influences on the abundance of ammonia-oxidizing bacteria (AOB) (8% and 3% for feed and rest periods, respectively), and nitrite-oxidizing bacteria (NOB) (5% and 2% for feed and rest periods, respectively). However, there was no influence of the rest periods on the denitrifying bacteria. AOB were only identified in the top layer (AOB β-proteobacteria) in both operational and rest periods. On the other hand, the NOB (Nistrospirae and Nitrospina gracilis) were identified in feed periods just in the top layer and during rest periods just in the intermediate layer. The denitrifying bacteria (Pseudomonas spp. and Thiobacillus denitrificans) were identified from the intermediate layer downwards, and remained stable in both periods. Based on the identified bacterial dynamics, the partially saturated VF wetland operated under low OLR enabled favorable conditions for simultaneous nitrification and denitrification.
authors.affiliation: GESAD-Decentralized Sanitation Research Group, Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Trindade, Florianópolis, Santa Catarina Zip Code 88040-900, Brazil.
authors.forename: Catiane
authors.initials: C
authors.lastname: Pelissari
authors.affiliation: GEMMA-Environmental Engineering and Microbiology Group, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Ávila
authors.affiliation: GESAD-Decentralized Sanitation Research Group, Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Trindade, Florianópolis, Santa Catarina Zip Code 88040-900, Brazil.
authors.forename: Camila Maria
authors.initials: CM
authors.lastname: Trein
authors.affiliation: GEMMA-Environmental Engineering and Microbiology Group, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: García
authors.affiliation: Department of Cellular Biology, Embryology and Genetics, Federal University of Santa Catarina, Trindade, Santa Catarina Zip Code 88040-900, Florianópolis, Brazil.
authors.forename: Rafael Dultra
authors.initials: RD
authors.lastname: de Armas
authors.affiliation: GESAD-Decentralized Sanitation Research Group, Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Trindade, Florianópolis, Santa Catarina Zip Code 88040-900, Brazil. Electronic address: pablo.sezerino@ufsc.br.
authors.forename: Pablo Heleno
authors.initials: PH
authors.lastname: Sezerino
mesh_terms: D001938:Brazil; D058440:Denitrification; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D011549:Pseudomonas / Q000378:metabolism*; D013855:Thiobacillus / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D062065:Wastewater; D053833:Wetlands
chemical_list: D009584:Nitrogen; D062065:Wastewater
keywords: Bacterial community structure; Low organic loading rate; Nitrogen removal; Treatment wetland