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item Dungan, Robert - Rob
item LEE, BRAD

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2007
Publication Date: 10/1/2007
Citation: Dungan, R.S., Lee, B.D., Shouse, P., De Koff, J.P. 2007. Saturated hydraulic conductivity of soils blended with waste foundry sands. Soil Science. 172:751-758.

Interpretive Summary: Each year foundries in the United States generate several million tons of waste sand that can no longer be used to make metalcasting molds. Beneficial use of waste foundry sands can divert a significant fraction of this material from landfills. Laboratory studies were conducted to determine the relationship between the waste foundry sand content in some common agricultural soils and the movement of water under saturated conditions. The soil textures used in our experiments were a sandy loam, loam, silty clay and clay. Each of the soils were blended with as much as 50% waste foundry sand and then packed into plastic columns. The data collected from this study indicate that the water movement in soils can be increased by the addition of waste foundry sands. Increased water movement in soils should allow for faster drying and better agronomic conditions.

Technical Abstract: Beneficial uses are being sought after for the large quantities of waste foundry sand (WFS) that are landfilled. Potential applications include their use in synthetic soils and incorporation into agricultural soils. In this laboratory study we investigated the saturated hydraulic conductivity (Ks) of sandy loam, loam, silty clay, and clay soils that were blended with WFS. Each soil was blended with 0 to 50% green sand (bentonite-coated sand) from an iron and aluminum foundry and a phenolic urethane no-bake sand from a steel foundry. The soils and foundry blends were packed into fixed-wall columns and Ks was assessed using the constant and falling head methods. The results showed that Ks generally increased in a linear manner as the WFS blending ratio was increased in the soils. Compared to soil only, Ks increases were the greatest in the loam and silty clay soils; at 50% WFS, Ks was as much as 235- and 600-fold higher, respectively. However, Ks was lower over the blending range in soils containing green sands that were predominantly coated with sodium bentonite as compared to calcium bentonite. We attribute this to the high swelling properties of sodium bentonite.