Stormwater Treatment Evaluation of a Constructed Floating Wetland after Two Years Operation in an Urban Catchment

Abstract

Constructed Floating Wetlands (CFW) for stormwater treatment are increasingly used to treat urban runoff. However, studies of large-scale systems and the long-term evaluation of their treatment efficiency are scarce. This article presents the final results of a two-year study of the pollutant removal performance of a CFW in a stormwater pond capturing runoff from a low-residential catchment in South-East Queensland (Australia) under subtropical conditions. Although the CFW treatment area to catchment ratio was only 0.14%, the results demonstrated a significant removal of both Total Suspended Solids (TSS) and Total Phosphorus (TP) from the stormwater inflows by the CFW. The efficiency ratios for TSS and TP were 81% and 52%, respectively. While the removal rate for total nitrogen was not significant for the CFW evaluated in this study, the ER was still 17%. However, the ERs for nitrate and nitrogen oxide were both 47%. The study results suggest that it may be possible to increase the pollution removal performance of the CFW by upsizing the system and including intermittent re-aeration zones in the surrounding stormwater pond. The results of this research study clearly demonstrate that CFW can be an effective treatment solution for the removal of pollution from urban stormwater runoff.

Sustainable Management and Successful Application of Constructed Wetlands: A Critical Review

“…For treatment of urban stormwater runoff, FWS CWs are mostly used. Walker et al [75], in their two-year field study, used a FWS design to treat stormwater runoff from an existing urban area in Queensland, Australia. However, there are some examples of the utilization of HSSF and VSSF designs as well.…”

“…where EMC in and EMC out are respectively the pollutant EMCs measured at the inlet and outlet of the system, µ EMCin and µ EMCout represent the mean of EMCs measured respectively at the inlets and at the outlets of the CW. Walker et al [75] calculated these two efficiencies by taking into account some of the common pollutants detected in urban runoff (TSS, TN, TP, NH 3 -N, NO 3 -N, NO x -N), measured over two years (Table 3).…”

Root and Shoot Biomass Growth of Constructed Floating Wetlands Plants in Saline Environments

“…Constructed Floating Wetlands (CFWs) are an innovative stormwater treatment technology, designed to mimic both the structure and function of naturally occurring floating wetlands [1]. CFWs consist of buoyant artificial medium which floats on the water surface and is planted with emergent wetland plants.…”

“…There have been numerous studies undertaken in the past to assess the nutrient removal performance of CFWs for stormwater runoff in freshwater environments such as lakes and ponds [1,2,5,6,7,11]. Headley and Tanner [7] reported on different plant species that had been used in CFWs worldwide for water quality enhancement in freshwater environments.…”

Study on the Application of Floating Beds of Macrophites (Vetiveria zizanioides and Phragmites australis) in Pilot Scale for the Removal of Heavy Metals from Água Forte Stream (Alentejo-Portugal)

“…FTWs are made up of floating matrices (floating bed), which are associated with ecological communities such as macrophytes and microorganisms (Kadlec & Wallace, 2009). The FTWs have been used since the 1900s in the US and 1920 in Japan (Ning et al, 2014), but are currently considered as an affordable and environmentally friendly technology for surface water eco-remediation (Walker et al, 2017).…”