Paper Mill Waste Reclaims Soil

Paper mill waste can safely be applied at a rate three times higher than the typical rate to reclaim soils of surface-coal mined areas. This is the first research project to determine the amount of paper mill sludge byproduct that can safely be applied to land without harming downstream water quality.

Agricultural Research Service soil scientist Martin J. Shipitalo at the North Appalachian Experimental Watershed in Coshocton, Ohio. found that a 300-ton-per-acre application rate of paper mill waste had many benefits, and did not result in major additional negative effects on runoff water quality compared to the standard 100-ton-per-acre rate.

The project also involved the two Ohio agencies that must grant special approval for the 300-ton-per-acre rate: the Ohio Environmental Protection Agency and the Ohio Department of Natural Resources. And it involved representatives of the paper mill, mining and land reclamation industries.

Shipitalo and colleagues applied sludge from a paper mill to plots on steep slopes in southeast Ohio that had been recently surface-mined.

Approximately 10 weeks after the application, grass was planted on the slopes.

The application of the sludge at both rates greatly reduced runoff and erosion from the plots, particularly during the period before grass was planted. But the higher application rate still reduced soil loss eight-fold after the grass was planted and the land had stabilized. Both rates reduced runoff three- to six-fold in that same post-planting period.

The high rate of paper mill sludge application increased soil carbon levels, soil pH and calcium to a greater extent than the lower rate. These improvements in soil quality may contribute to more persistent increases in plant growth and continued reductions in runoff and erosion. Also, the large reduction in runoff and erosion could result in lower reclamation costs by reducing the size of required sediment ponds. A paper on this research will be published in the November-December 2008 issue of the Journal of Environmental Quality.