Using Floating Islands to Treat Feedlot Runoff Water

Using Floating Islands to Treat Feedlot Runoff Water

Olds College researchers are evaluating the economic and environmental benefits of using native wetland plants and floating island technology to remediate feedlot runoff water. This research aims to effectively improve water quality for irrigation or livestock use by removing nutrients, heavy metals, and other contaminants — as well as minimizing the presence of algae blooms. Feedlot operators could access alternative, low-cost options for treating feedlot runoff water while being environmentally sustainable.

Emilie Edgar, research technician, tests equipment and gathers data from the feedlot holding pond on campus.

Contamination of surface water and groundwater from nutrient loading is a critical problem within agriculture and urban areas across Alberta and Canada. Feedlot wastewater can contain many different contaminants — such as solid and dissolved organic matter, nutrients, salts and heavy metals — and poses a risk to water supplies if it’s not contained and treated.

Past research has shown wetland plants are effective in capturing nutrients, but more critical information is needed. Olds College aims to fill that knowledge gap about the effectiveness of various native wetland plant species in removing specific nutrients and other contaminants for successful water remediation in its research project Floating Island Technology for Livestock Water Remediation.

This research on floating islands is a progression from previous, controlled environment trials at Olds College that evaluated water remediation using native wetland plants. The 2019 study examined nutrient and contaminant uptake of cattails, wheat sedge, sweet flag, smartweed and water sedge in a controlled, replicated experiment using water artificially dosed with high concentrations of macro nutrients. The results showed that macro nutrient removal was possible from all species with cattails performing the best overall due to its productivity and biomass production.

These findings were used to define a second controlled experiment — which ended in November 2020 — with additional plant species and feedlot runoff water collected from the Olds College feedlot holding pond. The results from both studies will be used to guide the selection of native wetland plants and the design, deployment, and maintenance of the floating islands in the latest research project.

Olds College is currently in its third phase of its floating island research with a three-year project which began in April 2021. Floating islands with select native plant species will be deployed in 2022 on catch basins at commercial feedlots to see if they can improve water quality to irrigation or livestock drinking water standards. Dr. Daniel Karran, hydrologist and instructor in the Werklund School of Agriculture Technology at Olds College, is the principal investigator responsible for managing the project activities, data analysis and technical reporting.

“Across all sectors, especially agriculture, one of the most pressing issues of our time is learning how to better manage our precious water resources,” explains Karran. “In operations that have negative impacts on water quality, we desperately need solutions that are economical and easily adopted so that producers can do more with the water they have, which minimizes their overall water footprint on the environment.”

The results of the previous phases of the floating island research have been very promising, so now we need to test this technology in real-world environments to determine if it is indeed the type of solution we are looking for.

View of the experimental setup within the greenhouse during the 2019 study.

The first “season” — from snow melt in the spring to freeze-up in the fall — will be used for baseline data collection. The quantity and quality of the water entering and remaining in all retention ponds will be assessed regularly, along with plant growth, plant health and plant nutrient profiles throughout the season. Using a variety of digital technologies and field sampling, concentrations of nutrients, fecal indicator bacteria, and other water quality parameters will be monitored along with climate and surface runoff variables. If successful, this technology will allow producers to reuse runoff water for livestock drinking water and irrigation, while minimizing risks associated with groundwater contamination, eutrophication and algae toxicity.

The number of floating islands — each four feet by eight feet in size — and selection of plants for each site will be based on previous studies and the water quality assessment at each site. It is estimated that between five to 25 per cent of the surface area for each pond will be covered with floating islands, and therefore the actual pond surface area will dictate the number of islands required per site.

This research aims to deliver specific information to inform the design and deployment of floating islands and native wetland plants for treating feedlot runoff ponds — a new low-cost process for treating feedlot runoff water — and information for the general public about the environmental footprint of livestock production and the steps the industry is making towards environmental sustainability.

Olds College understands the importance of providing livestock producers with alternative, natural, low-cost methods of water remediation so they can continue to be strong stewards of land and water.