1. Addressing the C/N imbalance in the treatment of irrigated agricultural water by using a hybrid constructed wetland at field-scale.
- Author
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Guerrero-Brotons M, Álvarez-Rogel J, Arce MI, and Gómez R
- Subjects
- Water, Nitrogen, Soil, Plants, Denitrification, Waste Disposal, Fluid, Carbon, Wetlands
- Abstract
To mitigate excess of nitrate-N (NO
3 - -N) derived from agricultural activity, constructed wetlands (CWs) are created to simulate natural removal mechanisms. Irrigated agricultural drainage water is commonly characterized by an organic carbon/nitrogen (C/N) imbalance, thus, C limitation constrains heterotrophic denitrification, the main biotic process implicated in NO3 - -N removal in wetlands. We studied a pilot plant with three series (169 m2 ) of hybrid CWs over the first two years of functioning to examine: i) the effect of adding different C-rich substrates (natural soil vs. biochar) to gravel on NO3 - -N removal in a subsurface flow (Phase I), ii) the role of a second phase with a horizontal surface flow (Phase II) as a source of dissolved organic C (DOC), and its effect in a consecutive horizontal subsurface flow (Phase III) on NO3 - -N removal, and iii) the contribution of each phase to global NO3 - -N removal. Our results showed that the addition of a C-rich substrate to gravel had a positive effect on NO3 - -N removal in Phase I, with mean efficiencies of 40% and 17% for soil and biochar addition, respectively, compared to only gravel (0.75%). In Phase II, the algae growth turned into a DOC concentration increase, but it did not enhance NO3 - -N removal in Phase III. In series with C-rich substrate addition, the largest contribution to NO3 - -N removal was found in Phase I. However, in series with only gravel, Phase II was the most effective on NO3 - -N removal. Contribution of Phase III to NO3 - -N removal was almost negligible., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)- Published
- 2023
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