| 1. |
- Kallner Bastviken, Sofia, et al.
(författare)
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Effects of vegetation and hydraulic load on seasonal nitrate removal in treatment wetlands
- 2009
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Ingår i: Ecological Engineering. - Amsterdam : Elsevier. - 0925-8574 .- 1872-6992. ; 35:5, s. 946-952
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Tidskriftsartikel (refereegranskat)abstract
- Optimising nitrate removal and identifying critical factors for nitrate removal in wetlands is an important environmental task in the effort to achieve better surface water quality. In this study, eighteen free water surface wetlands with similar shape and size (22 m2 each) received groundwater with a high nitrate-N concentration (about 11 mg l−1). The effects of two hydraulic loads, 0.13 m d−1 and 0.39 m d−1, and three vegetation types – emergent, submersed and freely developing vegetation – on the nitrate-N removal were investigated through mass inflow and outflow measurements.No significant difference in nitrate removal between the different hydraulic loads could be detected. Significantly higher area-specific nitrate removal and first-order area-based rate coefficients were found in the basins with emergent vegetation, with no difference between the basins with submersed and freely developing vegetation. The nitrate-N removal increased as the wetlands matured and the vegetation grew denser, emphasizing the role of dense emergent vegetation for nitrate removal at high nitrate concentrations.
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| 2. |
- Weisner, Stefan E.B, et al.
(författare)
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Influence of alternative states on nitrogen removal in experimental wetlands
- 2007
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Ingår i: 2nd International Symposium on Wetland Pollutant Dynamics and Control - WETPOL 2007. - Tartu : Institute of Geography, University of Tartu. - 9789949116881 ; , s. 357-359
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Denitrification is the main process that remove nitrate from the water in wetlands. Plants can supply denitrifying bacteria with organic carbon and suitable attachment surfaces (Weisner et al. 1994). They also promote the development of anaerobic conditions through litter accumulation and decomposition, which would favour denitrification. The presence of plants has been shown to enhance nitrate removal in field studies (Bachand and Horne 2000). Toet et al. (2005) found a higher nitrogen removal in wetland compartments with emergent plants than with submersed plants. Results from microcosm studies have shown that the potential for denitrification is specific for different plant species (Bastviken et al. 2005).Wetlands may typically exist in alternative states, dominated by different kinds of vegetation. The purpose of this study was to investigate the effect of alternative state on nitrogen removal under controlled conditions in experimental wetlands.
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