Mining requires huge amounts of water to extract valuable metals — and generates massive amounts of wastewater that must be cleaned according to strict environmental standards before being discharged.
This wastewater also provides an ideal habitat for microbes, and studying these can help reduce wastewater treatment costs and the environmental footprint of the mining industry, according to University of Toronto researchers.
The $3.7-million research project is funded in part by Genome Canada.
As professor Lesley Warren explains in a University of Toronto Engineering News blog post: “These wastewaters contain a variety of sulphur compounds that certain bacteria can use for energy.”
But until now, the ability to investigate how these bacteria are cycling the sulphur compounds has been limited. If these sulphur compounds become too concentrated, mining companies must implement costly chemical treatment systems before it can discharge wastewater. Otherwise companies may face toxicity problems — and resulting environmental enforcement and mitigation costs — in lakes or streams downstream from the mine.
“Mining companies know that microorganisms are driving these reactions, but its still a black box,” Warren said. “The lack of available technologies has meant that there has been little research to determine which bacteria are doing what, which ones could serve as early warning signals, or those that could actually be used as the biological treatment itself. Most importantly, mining companies don’t know which levers to pull to control the system.”
Identifying these levers will enable the research team to develop new tools to help mining operations better manage their wastewater, Warren says.
In other wastewater management news, MGX Minerals says it has extracted lithium, used to make batteries for electronics and vehicles, from heavy oil wastewater. The company is working to sign agreements with oil and gas producers to process their wastewater, which would otherwise be treated as waste, so MGX Minerals can extract lithium from that water, CEO Jared Lazerson told Financial Post.
The mining company says its technology reduces the production time of lithium from brine by 99 percent compared with conventional lithium brine production times.
The results are part of MGX Minerals’ ongoing deployment of a pilot plant in support of its 487,000-hectare Alberta lithium project. The pilot is scheduled to begin the first quarter of 2017.
Wood Mackenzie analysts estimate that lithium demand will double before 2024, with the vast majority of the growth coming from electric vehicles.
Photo Credit: Professor Lesley Warren/U of T Engineering