Flushing your toilet isn’t the end of the road for your waste, with approximately 20,000 to 25,000 tonnes of reusable fertilizer created out of Greater Sudbury wastewater solids per year.
This month, Niagara Falls-headquartered Walker Industries marked their 10th anniversary of operating Greater Sudbury's biosolids plant at the municipal Kelly Lake Road wastewater plant.
“It’s been very successful, the plant has operated for 10 years without issue,” vice-president of resource recovery Geoff Boyd told Sudbury.com this week. “We haven’t been down, and we’ve handled every drop of sludge they’ve sent us and turned it into fertilizer.”
Solids are treated and filtered at the city’s wastewater treatment plant on Kelly Lake Road, where it’s turned into slurry and pumped a few-hundred feet underground to the biosolids plant operated by Walker Industries.
There, it’s mixed with lime and nutrients through what Boyd described as a “patented process” through which it’s turned into a solid, sandy product which is a registered fertilizer with the Canadian Food Inspection Agency.
Trucks are loaded directly with the fertilizer, whose drivers transport it to various customers within a two-hour radius of Sudbury.
“As soon as it’s ready, we ship that truck out either to a mine site or directly to a farmer’s field, where they apply it and use it like any other type of fertilizer,” Boyd said.
The fertilizer is rich in nitrogen, phosphorus and potassium, he said, adding, “One of the huge benefits is, because the process mixes it with lime, it has a tremendous liming value.”
“Liming value” means it helps increase soil pH, which in the Greater Sudbury area tends to be low (acidic), “which limits your ability to grow crops, so this very quickly raises the soil pH, which allows nutrients to become available to the plants so they get a better yield.”
The end product is best suited for agricultural applications and has been used to restore former mining sites.
The biosolids facility was approved by city council in 2012 and received a national award from the Canadian Council for Public-Private Partnerships the following year, before the facility was operational. The public-private partnership was with N-Viro, which was acquired by Walker Industries early in the building process.
The plant was on time and on budget ($63.1 million, including $11 million from the federal government), opening in May 2015.
The effort was in the planning stages since 2007, and became necessary after the municipality was no longer able to dump wastewater solids, called “activated sludge,” at Vale’s tailings pond near Lively, with both the Ministry of Environment and Vale no longer accepting the practice.
“While this was once an acceptable practice, changing environmental standards and episodes of odour in nearby communities led the city to find a more permanent and sustainable method of sludge disposal and treatment,” a 2015 media release from the city noted.
Walker Industries is now at the halfway point in its 20-year contract with the city, after which the city will own the biosolids plant.
Tyler Clarke covers city hall and political affairs for Sudbury.com.