Floating wetlands

Floating wetlands

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• Key considerations
• Planning and design
• Construction and operation
• Links and references

Other name/s

Floating wetland, Floating treatment wetland

Description

Floating wetlands consist of a suspended matrix planted with wetland plants. This facilitates microbiological and plant processing of nutrients.

Floating wetlands encourage settling of sediments contained in the water and also remove nutrients due to plants roots.

The potential mechanisms that provide treatment in floating wetlands are known but the precise contributions are uncertain[1][3][4][5][6]. Plant roots are believed to play a major role in treatment processes within floating wetland systems as the water passes directly through the extensive root system hanging beneath the floating mat. The roots release enzymes, develop extensive biofilms and promote flocculation of suspended matter, at the surface of the submerged plant organs[1].

Other processes that may be important include plant uptake of nutrients and metals if harvested[3][4][5][6], enhancement of anoxic conditions in the water column beneath the floating mat, which promote microbial processes such as denitrification, and promotion of settling and binding of contaminants in the sediment pool[1].

Floating wetlands can be used in existing water bodies or waterways or in a purpose built pond. As they can be used in existing water bodies, they are particularly suited to locations where there is limited space for a constructed treatment wetland or similarly large treatment system.

Highly variable flows are likely to reduce the effectiveness of the treatment[2].

The main services floating wetlands provide include:

• Water treatment (sediment, nutrients and pesticides)
• Habitat
• Amenity

References

1. ^ a b c Headley, TR & Tanner, CC (2006), Application of Floating Wetlands for Enhanced Stormwater Treatment: A Review, vol. 324, Auckland Regional Council, Auckland.
2. ^ Nichols, P, Lucke, T, Drapper, D & Walker, C (2016), 'Performance Evaluation of a Floating Treatment Wetland in an Urban Catchment', Water, vol. 8, p. 244.
3. ^ a b Olguín, EJ, Sánchez-Galván, G, Melo, FJ, Hernández, VJ & González-Portela, RE (2017), 'Long-term assessment at field scale of Floating Treatment Wetlands for improvement of water quality and provision of ecosystem services in a eutrophic urban pond', Science of the Total Environment, vol. 584-585, pp. 561-571.
4. ^ a b Pavlineri, N, Skoulikidis, NT & Tsihrintzis, VA (2017), 'Constructed Floating Wetlands: A review of research, design, operation and management aspects, and data meta-analysis', Chemical Engineering Journal, vol. 308, pp. 1120-1132.
5. ^ a b Tondera, K, Blecken, GT, Chazarenc, F, Lucke, T & Tanner, CC (2018), 'Chapter 2 Treatment Techniques for Variable Flows', in K Tondera & et al. (eds), Ecotechnologies for the Treatment of Variable Stormwater and Wastewater Flows, Springer.
6. ^ a b Wang, CY, Sample, DJ, Day, SD & Grizzard, TJ (2015), 'Floating treatment wetland nutrient removal through vegetation harvest and observations from a field study', Ecological Engineering, vol. 78, pp. 15-26.

Last updated: 5 October 2018