Aridland constructed treatment wetlands I: Macrophyte productivity, community composition, and nitrogen uptake

Abstract

Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Ecological Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be re ected in this document. Changes may have been made to this work since it was submitted for publication. A de nitive version was subsequently published in Ecological Engineering, December 2016December , 97, 649-657, 10.1016December /j.ecoleng.2015 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Urbanized areas increasingly rely on constructed treatment wetlands (CTW) for cost 9 effective and environmentally-based wastewater treatment. Constructed treatment wetlands are 10 particularly attractive treatment options in arid urban environments where water reuse is 11 important for dealing with scarce water resources. Emergent macrophytes play an important role 12 in nutrient removal, particularly nitrogen (N) removal, in CTW. However, the role of plant 13 community composition in nutrient removal is less clear. Numerous studies have shown that 14 macrophyte species differentially affect N uptake processes (e.g.: direct plant uptake, coupled 15 nitrification-denitrification, soil accretion). However, many of these studies have been based on 16 small-scale experiments and have been carried out in mesic environments, which means that 17 their findings are difficult to extrapolate to aridland CTW systems. Our study sought to examine 18 the relationships among emergent macrophyte productivity, plant community composition, and 19 N uptake [by both the plants and the entire ecosystem] at a 42 ha CTW in arid Phoenix, Arizona, 20 USA. We quantified above-and belowground biomass bimonthly and foliar N content annually 21 for four species groups (Typha latifolia + T. domingensis., Schoenoplectus californicus + S. 22 tabernaemontani, Schoenoplectus acutus, and Schoenoplectus americanus) from July 2011 to 23 September 2013. We quantified dissolved inorganic N fluxes into and out of the system and 24 compared plant N removal to total system fluxes. Additionally, we estimated monotypic N 25 content for each to compare the system's current community composition and plant N removal to 26

Wetlands for Wastewater Treatment

“…CW planted with a polyculture of five ornamental flowering species removed up to 92% of PO4 3and 84% of NH4 + (Calheiros et al, 2015). Another study also found higher N removal in wetland with diverse plant communities than monotypic stands (Weller et al, 2015). Two large-scale CWs in South Florida achieved 77% to 84% of TP reduction over long term operation (Pietro and Ivanoff, 2015).…”

The efficiency of free-floating and emergent aquatic macrophytes in constructed wetlands for the treatment of a fishpond effluent

“…According to Chyan, Lu, Shiu and Bellotindos (), a TP removal rate of 93% in CWs with substrate could be attributed to the processes of retention and adsorption of particulate material. Besides the retention and absorption of particulate forms of N and P, some authors reported that the substrate itself favours the precipitation and sedimentation of organic and inorganic particles (Brix, Koottatep & Laugesen, ; Kumar & Zhao, ; Weller et al., ). In the CWs without substrates, the retention of particulate material, removal of TSS, and the retention of TP and TKN were lower than in the CWs with substrates, probably because the particulate material is only retained by sedimentation and/or by the roots of the free‐floating macrophytes (Henares & Camargo, ).…”

“…For example, the contribution of Phragmites australis to the removal of total phosphorus was less than 5% compared to a system without macrophytes (Vymazal, ). In the case of domestic wastewater, the reduction of inorganic nitrogen by emergent macrophytes was only 7% (Weller, Childers, Turnbull & Upham, ). Vymazal () reported less than 5% of N and P stocked in the plant biomass in a CW that employed emergent macrophytes.…”

Linking science and decision making to promote an ecology for the city: practices and opportunities

“…In our five years of studying the Tres Rios constructed treatment wetlands ecosystem, we have documented the productivity and nutrient assimilation capacity of the wetland plants and soils (Weller et al. ). We have also documented plant‐mediated control of surface water hydrology, for the first time in any wetland, in the form of a “biological tide” that is driven by plant transpiration that brings both water and nutrients from the open water areas into the vegetated wetland, where near‐complete nutrient removal takes place (Sanchez et al.…”