You may have heard of the ecological benefits of scattering wood ash in the forest or lake near your cottage, but you might not have heard of the novel substance “biochar” and its ability to reduce phosphorus levels in lakes—an increasingly prevalent chemical imbalance that leads to unsightly and destructive algal blooms each year.
Nutrient-rich wood residue bolsters calcium-starved lakes and soil in some areas of the Muskoka watershed, for example, but biochar achieves the opposite, by tying up over-abundant phosphorus and other damaging pollutants.
For decades, nutrients such as phosphorus and nitrate have infiltrated lakes in Ontario cottage country, making their way into pristine waters via runoff from farmers’ fields where fertilizers rich in these nutrients help boost agricultural production.
But when those nutrients hit the water, they disturb delicate aquatic ecosystems by over-fuelling the growth of naturally occurring algae. This, in turn, releases toxins and reduces oxygen levels, leading to massive die-offs of fish and filter-feeding invertebrates, according to the Canadian Wildlife Health Cooperative.
Not to mention algal blooms reek and can limit water-based activities during precious cottaging months.
But recent studies have shown that biochar can be manipulated to filter harmful nutrients such as phosphorus from water, preserving the delicate balance of these key ecosystems.
The substance is created by burning various types of organic waste in environments with little to no oxygen via a process called pyrolysis. The result is a charcoal-like material that can be used to improve soil conditions for farmers, sequester carbon, and even purify water.
One Ontario-based manufacturer of biochar says that while not all biochars are suited for water purification, high-quality and correctly engineered variations of the material are able to filter out unneeded nutrients due to their incredibly porous nature.
“If you look at our biochar under a microscope, you’re going to see a lot of pores,” says the CEO and founder of Bella Biochar, Jodi Formosi. “If you unravel one piece of biochar, it can open up to be the size of a football field—just to have an understanding of how layered it is and how porous it is.”
By burning the organic materials at higher than standard temperatures, Formosi says she is able to achieve high-quality biochar with superb absorption abilities.
“The biochar absorbs a ridiculous amount of its own weight,” she says. “Even though it feels very different, it’s like a sponge that just absorbs all of those contaminants and has a much larger capacity than its visual size, to absorb and maintain those nutrients and/or contaminants.”
Bella Biochar has been studied by researchers at Western University, who confirm the product has a much greater porosity level than other biochars produced using pyrolysis, allowing it to be more effective at removing contaminants from water.
At the moment, Formosi is the only biochar manufacturer that produces biochar in this fashion in Canada, but her product is already being used in five wetland restoration projects across Ontario, including at Roots Ridge Nature Reserve, Boyne Valley, and Hamilton’s Flamborough Centre Park.
At Flamborough Centre Park, for example, biochar is being employed to restore an under-used park into a treed wetland design, in part, to improve the quality of water flowing into the nearby Grindstone Creek, which feeds into Lake Ontario.
Though the material is in its early days as a tool for water purification, its proven ability to remove contaminants from bodies of water points towards a promising future for the continued effort to reduce algal blooms across cottage country.
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