Thirsty? How floating islands could turn retention ponds into potable water

Click to play video: 'Thirsty? How floating islands could turn retention ponds into potable water'
Thirsty? How floating islands could turn retention ponds into potable water
WATCH: With drought conditions plaguing farmers across Western Canada, a team of researchers at Olds College is looking at some inventive ways to make runoff water around farms and feedlots go the distance. Sarah Offin explores whether native plants may be able to turn the tides on water contamination – Aug 10, 2021

Olds College is hosting its AgSmart education expo Tuesday and Wednesday and, among the technologies on display, a new idea around potable water is being floated.

In a retention pond across from the campus feedlot, researchers are testing the water for contaminants and using islands of native plants to help with filtration.

Click to play video: 'The Benefits of Choosing Native Plants for Your Garden'
The Benefits of Choosing Native Plants for Your Garden

Usually water in agricultural retention ponds is pumped out and used for irrigation. But researchers Olds College Centre for Innovation are trying to give the ponds a higher calling — like providing drinking water for cattle or even humans.

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“Can we treat this water so that it can be used for other high-end uses?” said applied research manager Ike Edeogu.

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To answer that question, a team of researchers has employed some of the oldest custodians of the province: native plant species.

Floating islands are being launched into service in the campus greenhouse and retention pond, testing how effective plants like cattail, wheat sedge and water sedge are at removing contaminants.

Runoff from feedlots typically bring excess nutrients like nitrogen and phosphorus to nearby waterways. Coupled with hot, sunny weather, the nutrients can create the perfect breeding grounds for cyanobacteria. The resulting algae blooms can be harmful to humans and lethal to animals.

“There isn’t anything you’re actually doing to remove those nutrients from the water,” said Edeogu. “This is where the phytoremediation comes in.”

Phytoremediation essentially means using plants using plants to do the dirty work of removing contaminants from water.

Researchers at Olds College are using floating islands of native plants, like water sedge, in an effort to remove contaminants from water on farms. Bruce Alhus, Global News

Early research suggests seven of the tested species (small-fruited bulrush, Baltic rush, wheat sedge, water sedge, cattail, mare’s tail and smartweed) can remove phosphorus from the water, with removal rates between 77 and 84 per cent. Some plants also proved effective in reducing potassium levels by up to 45 per cent.

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The islands used so far in the project are about two feet by three feet wide, but next fall the school will deploy ones about four times that size in four water retention ponds around Alberta.

“We find that some plants are better at taking up a different type of nutrients while others are lower water users,” said research technician Krista Pick.

The project, receiving funding from the Alberta Real Estate Foundation, Highfield Industrial Group and Results Driven Agriculture Research, hopes to treat water on site.

The goal is to make it safe for cattle and possibly humans to consume  — something that could save feedlot operators both time and money.

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