Effects on the Underlying Water Column by Extensive Floating Treatment Wetlands

Abstract

Floating treatment wetlands (FTWs) are an emerging engineering option with promise for simultaneous water quality improvement and habitat creation. Relatively little research has been published regarding their construction or effects on the underlying water column. In this field-scale experiment, four different extensive FTW designs were constructed using minimal materials, including drainpipe, burlap, mulch, utility netting, and reused polyethylene bottles. The FTWs were then planted with spp. (cattail) and L. (common rush). Over 28 mo, the water column beneath FTWs in two test ponds was compared to that in an open water control pond. The ponds (190 ± 10 m) were fed with well water enriched with nitrate to emulate agricultural ponds. Although observed differences were relatively small, statistically significant differences were noted. With respect to the control, waters underneath FTWs had lower dissolved oxygen, sulfate, nitrate, and pH, dampened diurnal temperature fluctuations, and greater alkalinity. The FTWs created habitat and were colonized by species of insects, birds, amphibians, snails, and spiders. Results indicated that spp. is suitable for FTW creation. However, a more supportive planting matrix is suggested to encourage faster plant growth and protect against wind and wave action damage. Although plant growth was limited, results suggest that FTWs may be applied to encourage less aerobic and more organic rich and thermally insulated conditions for water quality improvement in agricultural ponds and other aquatic systems while also creating valuable habitat.

Neonicotinoid pesticide and nitrate mixture removal and persistence in floating treatment wetlands

“…The FTW treatments had FTWs established in the mesocosms for several months prior to the beginning of this experiment. Further, observations of lower DO concentrations in the FTW treatments were consistent with previous observations in environments with prolonged floating treatment wetland establishments (Strosnider et al., 2017). Although ORP dropped below 250 after Day 5 in control mesocosms, the presence of DO (4.0–5.1 mg L −1 ) and low C source (1.1–1.8 mg mg L −1 ) availability may account for limited NO 3 –N removal.…”

Field-Scale Constructed Floating Wetland Applied for Revitalization of a Subtropical Urban Stream in Brazil

“…Macrophytes were selected as recommended by Wang and Sample [34]: (1) native and non-invasive species, and (2) wetland plants with aerenchyma. The Typha dominguensis was selected due its native availability in Florianopolis, and its recognized performance in wastewater and stormwater treatment [35,36]. A density of 30 plants per m 2 or 6 plants per plastic crate was chosen, similarly tested by Rigotti et al [13] in mesocosm in south Brazil.…”

Floating Wetland Islands Implementation and Biodiversity Assessment in a Port Marina

“…They have identified several common colonizers similar to the ones found in the FWI, such as mussels, barnacles, and macroalgae. Other authors also mentioned the presence of several organisms in FWI implemented in freshwater ecosystems [32,33]. The biodiversity increment observed in the present study might be advantageous because some of these organisms, such as Ulva genus members, have the capacity to remove several pollutants [34], and mussels are ecosystem engineers, with capacity to form The upper surface of the platform was, in general, dry (with exception of periodic flooding due to waves from the tides), receiving total light exposure, which may explain the lower colonization.…”