What are floating treatment wetlands (FTW) and how do they work?
FTWs, also known as islands, are artificial platforms that allow aquatic emergent plants to grow in water that would have
otherwise been too deep for them. The roots of these plants spread throughout the floating platform, down into the water
creating a series of dense columns with increased surface area.
Both the platform and the roots provide an area for microbes to grow, not only so, the plants also take up nutrients and
contaminants, and allows for degradation of impurities. These islands also facilitate the reduction of turbulence and mixing
of sediments caused by winds and waves.
A unique self-sustaining ecosystem develops that absorbs and captures nutrients and converts pollutants found in lakes
into harmless byproducts, thereby FTWs improve the overall quality of water.
Where can FTWs be used?
FTWs can be implemented in many freshwater bodies, like for example:
They can improve the quality of water of ponds in urban and rural neighborhoods. Without FTWs the water would otherwise have been stagnate and would have allowed the accumulation of toxins.
Lagoons filled with wastewater, rich in pollutants, can benefit immensely from the treatment of FTWs. Landfill leachates and tailings ponds are another example. Leachate is a liquid that enters the landfill from an external water source such as rainfall, underground springs and groundwater, and from the liquid that is produced from the
putrefaction of waste. Whereas, tailings ponds are a mixture of water, sand, clay and *residual bitumen leftover from the
process in which sand and clay are separated from oil. All these toxins, metals and contaminants can be treated with FTWs.
* Materials obtained by processing the residue from the refining of naturally-occurring crude petroleum.
A project that is being further explored is how sites of oil spills can benefit from FTWs through breaking down oil elements.
What is the result from a successfully implemented floating treatment wetland?
Through the harvest and analyses of these aquatic plants, like cattail; evidence of nutrients that were taken up during the growing process were stored within the plant and as a result it has permanently been removed. Lakes that were high in phosphorous had much higher levels of productivity and root growth compared to lakes low in phosphorous.
This serves as an example of the effectiveness of FTWs.
To conclude, not only does FTWs improve the overall quality of water it also creates opportunities for economic growth that can improve the environment. If more floating treatment wetlands can be deployed within our freshwater bodies, we’ll be a step closer to the healing of nature, by nature!