The City of Edmonton is embarking on an ambitious project to rehabilitate the landscape around an Alberta coal mine and turn it into thriving field of willows using biosolids.
The Paintearth is an Alberta coal mine is near the village of Forestburg which is located 180 kilometres southeast of Edmonton. This is where they plan on conducting the reclamation experiment using biosolids converted from Edmonton’s sewage sludge.
The second phase of the experiment will involve the planting of willows on the reclaimed land. These are fast-growing, high-yield woody plants that can be used as a biomass feedstock for renewable energy products such as bioplastics.
The federal government has agreed to invest $3.8 million to fund the Alberta coal mine reclamation project. Other contributors include Alberta Innovates and Emission Reductions Alberta which have committed $1.5 and $2 million respectively.
John Lavery, principal scientist with Sylvis Environmental Services, says that the Alberta coal mine has a topsoil problem and a soil-quality problem but there is an abundance of organic matter. Sylvis is 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 claims.
“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,” he adds.
The Paintearth mine, which is operated by Westmoreland Mining, spans 6,200-hectares and has provided coal to the nearby Battle River power plant since 1956. It faces a very uncertain future however because of legislative changes regarding coal-fired electricity generation.
The federal government has mandated that all coal-fired energy generation be eliminated nationwide by 2030. This has compelled the Alberta Utilities Commission to approve a plan for the Battle River power plant to be converted from coal to natural gas to comply with this mandate. The mine currently has a contract to supply coal to the power plant until 2022.
The project calls for the application of biosolids as topsoil for the mine wastes to allow crops like willows to grow. If successful, the “energy crop” will be harvested every three years, according to Lavery.
The willows will also help replenish the soil with nutrients while trapping emissions underground.
“Willows are awesome. 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,” Lavery said.
To help with the team’s endeavor, the Canadian Forest Service has stated that they will lend their expertise to the project. Epcor is the company that will process and transport the biosolids from Edmonton to the reclamation site.
“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.”
They are hoping that the project will breathe new life into the mine and reclaim the land. It would also ease the impact of job losses during the transition into renewable resources.
“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. We’re not talking about cutting-edge technology. We’re talking about the right technology at the right time,” claims Lavery.
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