Floating island idea to clean up waterways takes hold in NZ
Head librarian Tish Potter introducing Bruce and Anne Kania. Photo: Ina Holst.
Ever considered building your own island, maybe an independent island republic made of shredded, recycled plastic?
It is not fiction anymore, Bruce and Anne Kania from Montana told a captivated audience in the library a fortnight ago.
The inventors of BioHaven Floating Islands have created a new wave of water stewardship that has already been extensively trialled by NIWA in New Zealand. Modelled on nature’s floating wetlands, which often occur naturally in peat lakes around the globe, the Kanias replicated and employed the same benefits to clean up waterways.
“Wetlands are nature’s kidneys for taking pollution out of water, and we are piggy-backing on that concept. It is hard to find a waterway that is not benefiting from wetland restoration,” Bruce said. “We have the research to prove the ability of floating island to remove nutrients [biosequester] and even heavy metal loadings from waterways. NIWA was first to collaborate with us to understand this technology and to experiment with cleaning up heavy metals, especially zinc and copper. Using the floating island idea in a one-square-metre tank, after two weeks 40 per cent of the zinc was removed from the water and 85 per cent of the copper. The hard work of science must now continue, as the momentum behind this concept is exploding.”
The building material—the matrix—that the Kanias have developed for the floating islands is a recycled polymer formed into layers and bonded with foam. It has a similar consistency to a pot scrub and can be turned into pads of any thickness to form floating docks, walkways or floating wetlands. These treat polluted water, simulate wildlife habitats, and clean up stormwater for effluent pond treatment and floating gardens.
The platform provides a secure medium for plant roots to grow through and a large surface area for beneficial microbes to colonise, and the non-woven matrix emulates the array of woody roots of natural systems, Bruce explained. As the island matures, the matrix and foam take on a subordinate role as the vegetation begins to support its own system and microbes form a biofilm on the roots, releasing biogas for buoyancy. These microbes are responsible for converting or removing nutrients and metals from the water.
“What prevents the microbes from taking over is surface area and circulation. Stagnant water and sunlight turn water into pea soup,” Bruce added.
The couple was inspired to do something about water pollution and the restoration of water quality after experiencing the problem first-hand on a stream flowing through their property that was loaded with nutrients, particularly nitrogen and phosphorus, from upstream farmland.
As a hobby angler Bruce had always been intrigued by the rich ecology and fish life surrounding floating wetlands, and this inspired him to have a closer look using biomimicry to fake the natural floating wetland effect. The artificial islands improve water quality by using the “dilution solution to pollution” the scientist said, they beautify waterscapes and create habitat for fish, invertebrates and waterfowl.
The idea can be employed in agriculture, aquaculture, urban settings, mining, wetland and lake restoration and even climate change adaptation, as CO2 is sequestered in organic matter, roots and microbes growing within the islands.
“NIWA is filming a documentary at the moment to show what can be done with floating islands from growing vegetables to using them as boat docks. Floating islands can provide a platform for some serious business, even growing your own country, and there is no more excuse to not take care of our water. It is not even expensive.”
In New Zealand, where today’s wetlands total only an estimated seven to ten per cent of the original area, the use of floating islands may contribute to a valuable solution to the continuous degradation of our waterways.
For more information contact <www.floatingislandsinternational.com>.
Ina Holst
