25 The Business of Prairie Agriculture Better Farming | April 2024 ing islands that Olds College are testing, have put these islands in use in diverse industrial settings. These floating islands are now in Phase 3 of agricultural testing through Olds College’s Floating Island Technology for Livestock Water Remediation research project. They have also been used in coal mining tailings ponds to clear out heavy metals and in urban storm ponds to mitigate the runoff of fertilizers, herbicides and other chemicals used in city parks. This project focuses on cleaning the storm ponds of the excess nutrients that run off from adjacent feedlots. Utilizing only plants that would naturally be found in Alberta’s wetlands, Phase 1, conducted in 2018, consisted of controlled greenhouse trials. Large tubs of water spiked with measured amounts of nutrients had a small-scale floating island installed on top. Various plants were tested in this controlled environment, such as sedges, rushes, cattail and smartweed, which performed well in absorbing the excess nutrients. Phase 2, also a controlled greenhouse trial, differed from Phase 1 in that the water used in the tubs actually came from the college feedlot. Results from this phase showed that the plants removed 45 to 84 percent of nutrients, depending on the species. Use of some plants ended once the project entered Phase 3 because “we’ve got environmental factors like wind and whatnot, and growing cattails on these big islands and big open areas is probably not practical because they are too large a plant,” says Daniel Karran, ecohydrologist and instructor at the Werklund School of Agriculture Technology, Olds College. Phase 3 began in 2021 as a threeyear data collection survey of four ponds near feedlots in the Linden, Alta. area. The first year consisted of collecting baseline data on the levels of contaminants in the ponds. This was measured with instrumentation like H-Flumes, In-Situ Aqua TROLL 600 Sondes, and YSI ProDSS – all instruments that periodically test a wide array of water quality parameters. Weather stations were also used to measure wind, temperature and precipitation. Larger islands on two of the ponds were installed in 2022, using two other ponds as controls. “We have 41 islands in one pond, and we have 14 in the other pond. We were shooting for five per cent coverage of the ponds,” says Karran. The islands are “about 4.5 x 8.0' in size. Then inside it, there’s a soil medium. It’s a peat moss medium that’s in there. Then there’s a plastic membrane between the soil and the medium that allows the roots to grow through the plastic membrane into the contaminated water below.” Testing with a mix of Baltic rush, sedges and chives, the islands were let RESEARCH SPOTLIGHT: FLOATING ISLANDS
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