August 2008

One part yellowcake, three parts cheese?

Addition of cheese whey cuts down the time and cost of environmental remediation process

By D. Zlotnikov

When it comes to uranium and the environment, public opinion has been divided for years. Some environmental groups view nuclear power as the solution to the carbon emission problem, but others point to the damage caused by the extraction process and the risks inherent in storing the spent fuel.

Cameco, a major producer of uranium yellowcake, has been improving the extraction side of the equation for years. But a recent process improvement comes from a most unusual source — cheese whey.

Cameco’s operations include the in-situ Smith Ranch mine in the United States. To extract the uranium, the groundwater is pumped out, mixed with sodium bicarbonate and pumped back into the mine. There, the mixture dissolves the uranium and is then pumped back to the surface where the uranium is extracted. The final step in the process, as part of the environmental remediation program, is to return the groundwater to its original composition.

Until recently, that final step was costly and time-consuming, requiring the use of significant amounts of chemicals. However, a Cameco research team has found a new approach that has drastically cut down the time and cost involved: adding cheese whey to the mix. The whey, a nutrient-rich byproduct of cheesemaking, serves to encourage growth of the bacteria historically found in the local rock formations. In turn, the bacteria cause a dramatic reduction in the contaminants, uranium and selenium remaining in the water.

This bioremediation approach has proven to be cheaper, safer and more environmentally friendly than previous methods, and Cameco intends to implement the technique, which is currently in the process of being patented, at the Crow Butte in-situ operation as well.

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