Olds College of Agriculture & Technology has released its initial findings about whether native wetland plants can be superheroes when it comes to cleaning up the water in cattle feedlot ponds.
“Cattle feedlots have to collect all the stormwater that runs off of their operations into holding ponds,” said Dr. Daniel Karran, who is an ecohydrologist at the College’s Werklund School of Agriculture Technology. Karran is the principal investigator responsible for managing the activities, data analysis and technical reporting for this project led by Olds College Centre for Innovation (OCCI).
“And you can imagine that, after rain falling on a feedlot with 10,000 head of cattle, what is going into that pond,” he said, referring to contaminants ranging from manure and E. coli to antibiotics and heavy metals. “It’s very dirty and we can’t really use that water for anything else.”
Increasing drought in regions such as Western Canada spurred by climate change is making it imperative that the agriculture industry find cost effective ways to treat and clean its wastewater, said Karran. “The industry is the largest consumer of water, and when water resources are scarce, they feel it the most.”
Karran unveiled his team’s initial findings at the recent Olds College Research Showcase — an event on campus that highlighted the research activities of faculty, staff and students. His project involved the testing of innovative floating islands, each measuring four feet by eight feet, that acted as rafts for wetland plants to grow roots into the surface of wastewater ponds at two cattle feedlots near Linden, Alta.
Plants such as Baltic rush (Juncus balticus) that are native to Alberta, as well as much of the Americas and Eurasia, were grown in layers of peat moss on a total of 55 floating islands that simulated wetland environments. It caused the plants to naturally absorb contaminants from the wastewater through a process called phyto-uptake.
Researchers found the plants removed 69 per cent more ammonia (NH3), 55 per cent more total phosphorus and 27 per cent more total nitrogen compared to a College feedlot pond that lacked the islands, said Karran. High ammonia concentrations in water are harmful to aquatic life and cattle, if consumed, he said.
“Some of these micronutrients actually showed pretty high removal rates in our testing and so, yes, it’s pretty cool. There was an impact. I haven’t totally processed these results yet, but the phosphorus actually went up in the Olds College pond.”
Total nitrogen and phosphorus refer to the total amounts of these elements found in the water from both organic and inorganic sources, he said. “They are the key nutrients for vegetative growth, and high concentrations in water can lead to harmful algae blooms.”
Researchers also found that 93 per cent more copper, 81 per cent more aluminum and 77 per cent more zinc was removed at the ponds compared to the College feedlot pond, said Karran. Heavy metals can be harmful at high concentrations, he said.
Karran cautioned the research project’s results are preliminary and are still being examined. The financial feasibility of cattle feedlots using the floating islands must also be analyzed, with the final results of the study expected to be completed by September, he said.
The floating islands were developed and patented by Tannas Conservation Services Ltd. of Cremona, Alta. They have been used since 2015 to treat everything from wastewater at a coal mine in Alberta, and a diamond mine in Ontario, to city stormwater in Lethbridge, Alta., said president Dr. Steven Tannas.
He expected that besides cattle feedlots, the floating islands could also potentially be used to treat wastewater from livestock sectors ranging from poultry to pigs. These wetland plants are native to much of the northern hemisphere and the technology could potentially be used in other countries, said Karran.
The floating islands essentially make up an environmentally-friendly, natural technology powered by free sunlight, said Tannas. “And really the focus was on using native plant materials so we don’t have weeds, and it’s passive so that you don’t need an active water treatment facility, so it can be very cost effective over the long term.”
College researchers tested an initial seven species of wetland plants. Three species survived the 2023 and 2024 seasons of the third phase of the cattle feedlot project: Baltic rush, water sedge (Carex aquatilus) and wheat sedge (Carex atherodes).
Although the best results were obtained with Baltic rush, more testing is needed, said Karran. “There are other questions that need to be answered because even though you have good results from one plant, a community of plants might be more effective.”
He is also considering testing the floating islands in farm dugouts. “This technology could be really useful in those environments because cattle are suffering injuries and even death from drinking water contaminated with sulfates and harmful algal blooms, all things that come from the contamination of these systems and can potentially be remediated with floating island treatments.”
