In 2000, Bruce Kania’s black dog, Rufus, jumped into a pond and came out red. Concerned for his dog and wondering what was going on, Bruce also saw a tremendous opportunity for invention, if he could develop a new and natural stewardship tool which could clean water and, in the process, improve life for all the creatures who live in it.
Bruce brought together a team of engineers and plant specialists turned to the floating peat bogs of Northern Wisconsin, where world-record fish are to be found within crystal-clear waters, for inspiration: The team set about “biomimicking” these floating riparian structures.
Using a matrix made of post-consumer materials. such as recycled plastic drink bottles, they created an island capable of supporting the weight of plants and soil. The fibers within the matrix proved to be excellent material for growing biofilm, while still allowing water to pass through it. This allowed unwanted nutrients to be “eaten” by bacteria forming on the island and in the plant roots.
In 2005, Bruce and his partners forme Floating Islands International and opened a prototype production facility in Montana. Within the first two years of operation, 1,600 islands had been launched in the United States, Canada, Australia, New Zealand, Singapore, UK, Korea and Europe. By 2010, over 4,000 islands had been launched, and over 30 different applications had been identified for floating islands.
Hydraulically, the floating islands behave like a stormwater detention pond, while their treatment processes is that of a wetland. The floating matrix, plus the plant roots hang beneath it, provide a large surface area for biofilm growth which forms an important part of the treatment “reactor.”
The microbes and macrophytes uptake nutrients and move them into and through the food chain. Suspended organic particles stick to the biofilm and become periphyton, food for scuds, nymphs and ultimately fish. Suspended inorganic solids, such as heavy metals in particulate form, slough off and settle in the benthic zone beneath the island. The island is a sink for carbon dioxide and it enables nitrates and ammonia to be removed from the water and safely converted back to Nitrogen gas. This process prevents or slows down eutrophication and keeps the aquatic system in balance.
Forced circulation of water through the floating island matrix to gain maximum contact with biofilm has been shown to increase the effectiveness of the floating island up to 500 percent.
Floating islands have been demonstrated to remove all the typical wastewater parameters of concern – ammonium, nitrate, phosphorus, organic carbon and suspended solids — within a single island body.