BABBITT— The ongoing debate over the regulation of sulfate discharges from Iron Range taconite mines has centered, at least to date, on the perception that expensive reverse osmosis is the only proven technology capable of reaching the sulfate levels required under Minnesota’s standard for discharges into wild rice waters.
With engineers’ estimates suggesting a reverse osmosis facility at the Keetac plant could cost more than a billion dollars to construct and operate, mining officials and representatives of the steelworkers union have raised the alarm about the potential for further mine closures and job losses if companies are forced to install expensive new pollution control measures.
Yet, locally produced technologies, like the one under development by Babbitt-based Clearwater BioLogic, have the potential to all but eliminate concerns over the cost of sulfate controls, create new good-paying jobs in the region, and generate valuable byproducts that could turn pollution control from a business expense, to a potential profit center.
The full potential of Clearwater’s technology should become clearer next summer, assuming that a $727,000 grant from the Legislative-Citizens Commission on Minnesota Resources, or LCCMR, which was already approved by the LCCMR board, is ultimately greenlit by the Legislature. The grant will fund a one-year study of Clearwater’s now-patented technologies, which are incorporated into a mobile lab to be positioned along the Dunka River. The river has elevated sulfate levels due to discharges from the Peter Mitchell taconite pit and those discharges eventually wind their way into the otherwise pristine waters of the Boundary Waters Canoe Area Wilderness.
The mobile lab is already built, but with a capacity to treat just 7,000 gallons a day it’s designed primarily to fully test the process and prove that it can be scaled up to meet much higher rates of flow.
As the Timberjay has previously reported, much of the new technology developed by Clearwater BioLogic is well-documented and straightforward. An initial bioreactor relies on sulfur-reducing bacteria, that derive energy from stripping oxygen atoms from sulfate, to reduce sulfate to hydrogen sulfide. Then, an entirely separate process developed more recently by the company converts the hydrogen sulfide to iron sulfide using electrodes composed of pellets of direct reduced iron. The iron sulfide is a potentially valuable end product, according to Bill Newman, who is president of Twin Cities-based RNAS Remediation Products and co-founding partner in Clearwater BioLogic with Jeffrey Hanson, of Babbitt. Newman said the resulting iron sulfide, which is known as mackinawite in its purest form, currently sells for $10 a pound in dry form or $1 a pound in a 10 percent water solution. That means, said Newman, that every ton of sulfate removed could potentially generate $18,000 worth of byproducts. He acknowledges that some impurities in their iron sulfide could limit its value somewhat, but he said if the company could get even ten percent of the price of the pure product, it would easily cover the cost of the sulfate treatment.
And at least one other byproduct of the process may soon have commercial value as well. Over time, the electrodes comprised of direct reduced iron are coated with a layer of sulfide, which makes them less efficient. But rather than throwing them away, Newman believes the sulfur-coated pellets could take the place of another iron product currently being used to bind heavy metals in other water remediation efforts. He said the current product tends to oxidize quickly, making frequent replacement necessary, but it’s been shown that a coating of sulfide keeps the iron reactive for much longer.
Newman, who has an extensive background in water remediation, has been a primary funder of Clearwater’s development work since the company’s start-up in 2018 and his experience on the biological side of the operation has helped to fine tune some of the key processes, such as the feeding of the sulfur bacteria, which subsist on the sulfate in the water that passes through the bioreactors as well as a mixture of ethanol and glycerin, that provides another key source of food for the microorganisms.
The methods developed by Clearwater are ingenious yet surprisingly low-tech and, according to Hanson, that allows them to treat sulfate down to very low levels, well under the 10 milligrams per liter wild rice standard, for minimal expense compared to reverse osmosis, certainly no more than $2,000 per metric ton of sulfate removed.
While the basic technology appears sound, the only major remaining question is how quickly they can flow water through their bioreactors to achieve the required sulfate reduction. Answering that question will help them pin down how many bioreactors would be needed to treat the volumes of discharge from area mines. Since the bioreactors are built as modules, they can install an almost unlimited number but knowing the maximum flow that can effectively pass through each module is key to determining how many modules it will take at any one mine site, and what the installation and operating costs are likely to be. Hanson said his projections, based on what they know to date, suggest that a system to treat discharge from Keetac could be built for $3-5 million and cost $3-4 million annually to operate. According to financial projections produced for U.S. Steel by Barr Engineering, the costs of installing and operating a reverse osmosis system would exceed a billion dollars over 20 years.
Advancing a sulfate solution
One might expect that a new and relatively inexpensive method for treating sulfate would be welcomed with open arms by U.S. Steel, which is facing sulfate regulation in the new permit for its Keetac facility. But the company has been cool, to date, to Clearwater’s outreach.
Instead, the company has cited reverse osmosis as the only viable solution, suggesting that the high cost could force mines to close. “There are other solutions,” said Hanson, “but the company has taken the tack that it’s too expensive and we’re just going to shut down.”
That’s a political approach that, to date, has allowed the company to attract support from mine workers and Iron Range officials for loosening the wild rice standard.
Supporting development of a much-cheaper alternative would plainly undermine the company’s argument that it can’t afford to treat its discharges of sulfate.
Hanson said the company has been explicit about that in private conversations with him.
“When we presented our stuff and costs to them, they looked me straight in the eyes [and said], ‘it still costs less to do nothing.’ But will they say that publicly? Probably not.”
When contacted by the Timberjay, U.S. Steel took issue with Hanson’s claim.
“U. S. Steel takes its commitment to environmental excellence very seriously,” said spokesperson Andrew Fulton. “To suggest that we would dismiss our obligation to address sulfate is utterly absurd. We worked with Clearwater BioLogic to conduct lab scale testing where they were able to test approximately 20 gallons of water per day. Keetac discharges several thousand gallons of water per minute. Clearwater’s technology requires a large footprint and, while it does reduce some sulfate at a small scale, it does not address all pollutants. This technology may have a future applicability, but it is not ready for commercial use.”
While U. S. Steel has largely dismissed Clearwater’s process, some Iron Range political leaders are taking a closer look. Hanson said state Reps. Roger Skraba and Cal Warwas, as well as state Sen. Robert Farnsworth, have all visited the company’s mobile lab. Third District Sen. Grant Hauschild, who has, to date, pushed vehemently for loosening sulfate regulations, visited Clearwater’s mobile lab last week to learn more about the process. Hauschild, who sits on the Senate Environment, Climate, and Legacy Committee, will be one of the key decisionmakers for advancing the LCCMR grant next session and he said he will strongly back the funding for Clearwater’s Dunka River project.
Hauschild said he was impressed with the work Hanson and Newman were doing. “It’s great they’re trying to solve this at the grassroots level,” he said, and agreed that the state should play a role in demonstrating the scalability of the process the company has developed.
In the meantime, however, he said he is opposed to any sulfate regulation that could put mine workers’ jobs at risk. “We’re not going to be putting our mines in a position to close,” he added.
But if Clearwater’s process proves to be a viable solution after next year’s testing, Hauschild said he’d be open to a different approach. “If we have a legitimate and affordable way of meeting this standard, it’s a win-win,” he said. “That’s just not the case right now.”