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Purdue Agriculture researchers are experimenting with plants that will grow in slag, a byproduct of steel production, at the
U. S. Steel complex in northern Indiana. |
Near the southern shore of Lake Michigan there’s a small land area with a growing problem: The problem is that little will grow there. Located within the United States Steel Corp. complex in Gary, Ind., this area contains heaps of slag, the byproduct from the processing of steel. The slag has piled up over the years and looks like black dust mixed with gravel and metal fragments. While it seems like dirt, it’s void of many of the components necessary for good soil.
Yet it’s on these hills adjacent to the scenic Great Lake that Paul Schwab envisions greener, friendlier confines. Schwab is working with John Graveel, a fellow faculty member in Purdue University’s agronomy department, to try and get these barren areas to sprout new life.
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Soil isn’t necessary to grow plants, according to Purdue scientists Paul Schwab (left) and John Graveel. They use plants to help reclaim industrial land, including slag from steel production and soil saturated with fuels. |
U. S. Steel officials share this vision and last year contacted Graveel to see if something could be done to reinvigorate the landscape around the plant. The call came from one of Graveel’s former students, Julie Smock, who works in the plant’s Environmental Control Division. Smock, a 2006 graduate of Purdue Agriculture’s Natural Resources and Environmental Sciences program, told her former professor that the company wanted to experiment with vegetating the slag that has accumulated for decades around the facility.
Challenging conditions
Slag is currently recycled for such uses as asphalt base on roadways and some nursery products. Slag has also been used extensively for fill material for plant construction. But early in the plant’s history, that was not the case. For each ton of steel, there’s a quarter ton of leftover slag. With high salt, metal and pH-levels, the slag is hospitable to only the hardiest of plant species, as evidenced by the cottonwoods and weeds that dot some of the older lots.
But Schwab has been “growing plants in horrible conditions for a long time,” he says. While most people try to plant in the best soil they can find, he has long been attracted to putting his “green thumb” to work in some of the worst conditions possible. Among his efforts are reclaiming petroleum-laced soils in the San Francisco Bay and rescuing land saturated with diesel in Virginia at the largest naval fueling depot in the world.
Previous attempts by U. S. Steel to “green up” its complex included bringing in large amounts of dirt and mixing it with the slag. In this current challenge, the emphasis is to find out how successfully plants will grow in the slag, with very little added material.
Three 40-by-60-foot sections and one 20-by-10-foot section of slag were cordoned off for tilling and planting. In one area, it’s the equivalent of trying to grow a garden on a gravel parking lot. Smock laughs and says when they picked the spot, her boss told her, “It’s Purdue. Let’s give them a challenge.”
The plants of choice for this experiment are a grass mix and switchgrass, the green fodder that might someday be the feedstock for cellulosic ethanol. Schwab says if the test proves successful, U. S. Steel might someday be able to harvest the switchgrass and sell it for fuel. However, at this point, company officials are just pleased to reclaim the area.
As Nick Dernick, an environmental engineer at U. S. Steel, says, “A lot of people are happy to hear about what we are trying to do up here. We want to make this a more attractive place, and, more important, stabilize the environment.”
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