Performance Evaluation of a Full‐Scale Constructed Wetland for Treating Stormwater Runoff

Abstract

The performance of a stormwater wetland consisting of a retention pond followed by a horizontal subsurface flow (SSF)‐constructed wetland is evaluated during 11 stormwater events. Samples collected from the inlet and outlet of the wetland are analyzed for total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH4+‐N), nitrate (NO3−‐N), PO43−, total phosphorus (TP), and trace metals. Despite the high variability in inflow concentrations, high removal efficacies for TSS (84.3%) and COD (79.2%) are observed. The overall nitrogen removal is satisfactory with a removal efficiency (RE) of 53.5% for TN, 56.5% for NH4+‐N, and 76.5% for NO3−‐N. Lower inflow concentrations limit the TP removal (29.5%) and can allow previously sorbed phosphorus to be released from sediments into the water column. In addition, retention pond is limited in removing dissolved and fine fractions. Lower concentrations of heavy metals are observed compared to influent, and the average RE is 67.2% for Zn, 73.2% for Cu, 41.7% for Cr, 7.1% for Cd, 44.1% for Ni, and 60.6% for Pb, respectively. Relatively high levels of Zn in the roots of Phragmites australis are observed, followed by Cu, Ni, and Cr. Mean concentrations of TSS, TN, and TP are all moderately correlated to inflow intensity during stormwater events in contrast to dissolved nutrients. Flow intensity and effluent concentrations of TSS, TN, TP, and PO43− are also significantly positively correlated.

Assessing nitrogen and phosphorus removal potential of five plant species in floating treatment wetlands receiving simulated nursery runoff

“…Unlike traditional constructed wetlands, FTWs float and so can adjust to water level fluctuations (Headley and Tanner 2007;Lane et al 2016). FTWs have been used and evaluated for treatment of urban stormwater (Borne et al 2013;Li et al 2017;Winston et al 2013), overflows from combined sewage systems (Shen et al 2018;Van de Moortel 2008), acid mine drainage (Smith and Kalin 2000), agricultural runoff, and other waste waters (Chen et al 2016;Stewart et al 2008). Benefits associated with FTWs include improved water quality, reduced shoreline erosion, and provision of wildlife habitat (Borne et al 2015;Lynch et al 2015;.…”

Assessing Hydrological Effects of Bioretention Cells for Urban Stormwater Runoff in Response to Climatic Changes

“…Due to their flexibility of scale, BCs' positive life-cycle benefits can be effectively integrated into dense urban areas [32][33][34]. BCs have been widely applied in urban areas through strong support from local governments, such as in the Sponge City program [35].…”

Floating Wetlands: A Sustainable Tool for Wastewater Treatment

“…Although plants can partially degrade the organic compounds, nevertheless, complete degradation is indispensable without effective partnership with microorganisms . The partnership can be neutral, commensal, and dormant . Plant roots are the primary site for bacteria to colonize plant tissue.…”

“…[76,77] The partnership can be neutral, commensal, and dormant. [75,[78][79][80] Plant roots are the primary site for bacteria to colonize plant tissue. However, they do not remain limited to roots surface but can also enter the plant to dwell inside and to get nutrients.…”