Using Smokestack Waste To Reclaim Strip Mines

Smokestack scrubbers installed on coal power plants to cut sulfur dioxide emissions can generate up to 22 tons of waste an hour--a mixture of ash, limestone, and gypsum. Big landfill problem, right? Not to Ohio State University agronomists, civil engineers, and economists. They're experimenting with using the waste to reclaim coal strip mines, to enrich the soil of farms, and to create a concrete-like building material.

The researchers treated soil samples from coal mines with scrubber byproduct. That reduced the soil's acidity so much that hardy grasses and alfalfa grew well, raising hopes that scrubber waste could restore strip mines that today resemble barren moonscapes. The grasses were safe for animals to eat. And water that leached out of the test sites met Environmental Protection Agency standards for agricultural use, says head researcher Warren Dick, an agronomist. Pending EPA approval, the method will be used on real mines starting next spring. The Ohio State team is also experimenting with spreading scrubber waste on acidic farmland, either alone or combined with nutrient-rich sewer sludge. A final use is to make it into a kind of concrete for roads or the floors of cattle feedlots.

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