Organic waste from Edmonton could help transform the landscape surrounding an Alberta coal mine into a thriving crop of willows.
The reclamation experiment will use treated Edmonton sewage sludge to replenish soil at the Paintearth mine near Forestburg, a village 180 kilometres southeast of the city.
The nutrient-enhanced soil, in turn, will be used to grow a crop of willows — fast-growing, high-yield woody plants that can be used as a biomass feedstock for renewable energy products such as bioplastics.
On Monday, the federal government announced $3.8 million in funding for the project. Alberta Innovates and Emission Reductions Alberta also committed $1.5 and $2 million respectively.
“The mine has a topsoil problem and a soil-quality problem. And the city has an abundance of organic matter,” said John Lavery, principal scientist with Sylvis Environmental Services, the B.C.-based environmental consulting firm leading the project.
“We’re not talking contamination or chemicals. We’re talking about a lack of topsoil, period,” Lavery said in an interview with CBC News.
“A site, in order to be productive again, needs a certain depth of reasonably high quality veneer of topsoil across its surface, and we can achieve that.”
Operated by Westmoreland Mining, the 6,200-hectare surface strip mine has provided coal to the nearby Battle River power-generating station since 1956. But its future is uncertain.
All coal-fired electricity generation is set to be eliminated nationwide by 2030. Last year, the Alberta Utilities Commission approved a plan for the Battle River power plant to be converted from coal to natural gas.
The mine, which has two active pits, has a contract to supply coal to the power plant until 2022.
‘Willows are awesome’
Some areas of the experimentation site will be fertilized with biosolids. In areas with no topsoil, a thick layer of biosolids will be added to create a new layer of healthy dirt.
The willows will also help replenish soil that has been depleted of nutrients while trapping emissions underground.
“Willows are awesome,” Lavery said. “They grow a ton of woody biomass very, very quickly.
“And while this system is producing all this biomass above ground, it is sequestering carbon, at an incredibly fast rate, below ground. This system stores carbon.”
The Canadian Forest Service will lend its expertise to the project.
Epcor crews will process and transport the biosolids from Edmonton to the reclamation site. The mine will provide the workforce.
“We are doing a lot of technology transfer and skills transfer at the mine itself to make sure that the current workforce at the mine are ultimately the workforce that will continue the work with this biomass system,” Lavery said.
“As the mine work tails off, this work should be able to pick up and fill some of that void.”
The project is seen as a way to breathe new life into the mine, reclaim the land and help soften the blow of impending job losses by establishing a renewable resource.
Work on the reclamation experiment began last December but the idea has been in the works for two years.
Willows have been used as an energy crop across North America and throughout Europe for decades but this is the first time they will be tested for reclamation, Lavery said.
“We’re not talking about cutting-edge technology. We’re talking about the right technology at the right time.”