Nitrate removal processes in a constructed wetland treating drainage from dairy pasture |
| |
| Authors: | Fleur E Matheson James P Sukias |
| |
| Institution: | 1. Umweltbundesamt (FG Trinkwasserressourcen und Wasseraufbereitung), Schichauweg 58, 12307 Berlin, Germany;2. Kompetenzzentrum Wasser Berlin (KWB), Cicerostrasse 24, 10709 Berlin, Germany;3. The Wetlands Institute – 1075 Stone Harbor Boulevard, Stone Harbor, NJ 08247, USA;4. Technische Universität Berlin (FG Standortkunde und Bodenschutz), Ernst Reuter Platz 1, 10587 Berlin, Germany;1. Hydrosystems and Bioprocesses Research Unit, Irstea, Antony, France;2. Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia;1. Department of Catchment Hydrology, UFZ – Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, 06120 Halle/Saale, Germany;2. Department of Environmental Biotechnology, UFZ – Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany;3. Department of Soil Physics, UFZ – Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, 06120 Halle/Saale, Germany;4. Department of Biotechnology for Water Treatment, BTU-Cottbus-Senftenberg, Cottbus, Germany;5. Department of Microbiology, Institute for Water and Wetland Research, Radboud University of Nijmegen, Nijmegen, The Netherlands;1. Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD 57006, USA;2. Iowa Soybean Association, 1255 SW Prairie Trail Pkwy, Ankeny, IA 50023, USA;1. Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA, Waste and Wastewaters Laboratory USER-R4R, Via Martiri di Monte Sole 4, 40129, BO, Italy;2. Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA, Agrifood Sustainability, Quality and Safety Laboratory BIOAG-SOQUAS, Via Anguillarese 301, 00123 Santa Maria di Galeria (RM) Italy;3. Via di Monte Pendola 3-00061 Anguillara S., RM, Italy |
| |
| Abstract: | 15N-labelled NO3? was used in a surface-flow constructed wetland in spring to examine the relative importance of competing NO3? removal processes. In situ mesocosms (0.25 m2) were dosed with 2 l of 15NO3? (NaNO3, 300 mg N l?1, 99 atom% 15N) and bromide (Br?) solution (LiBr, 4.3 g l?1, as a conservative tracer). Concentrations of NO3?, Br?, dissolved oxygen and 15N2 were monitored periodically and replicate mesocosms were destructively sampled prior to and 6 days after 15N addition. Denitrification, immobilisation, plant uptake and dissimilatory NO3? reduction to NH4+ (DNRA) accounted for 77, 11, 9 and 2% of 15NO3? transformed during the experiment. Only 6% of denitrification gases were directly measured as atmospheric or dissolved 15N2; the remainder (71%) was determined via 15N mass balance. This indicated that a large proportion of the denitrification gases were entrapped within the soil matrix and/or plant aerenchyma. The floating plant Lemna minor exhibited a significantly higher NO3? uptake rate (221 mg kg?1 d?1) than Typha orientalis (10 mg kg?1 d?1), but periodic harvest of plants would remove <3% of annual NO3? inputs. Our results suggest that this 6-year-old constructed wetland functions effectively as a sink for NO3? during the growing season with less than one-quarter of the NO3? processed sequestered into wetland plant, algal and microbial N pools and the balance permanently removed by denitrification. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
