Toxic Waste Finds a High-Tech Future in Semiconductors

Around the globe, communities that rely on groundwater for drinking must first extract naturally occurring arsenic from the supply. Even at low levels, this toxic metal can raise the risk of cancer, and chronic higher doses can cause symptoms ranging from gastrointestinal distress to cardiovascular disease to nerve damage.

Treating drinking water from arsenic is simple enough — most treatment plants use iron oxides to bind to the metal and then filter it out — but the result is a concentrated iron-oxide-and-arsenic sludge that must be disposed of. Wealthier countries landfill this sludge, which can still necessitate multiple treatment cycles as the arsenic leeches out and must be recaptured. In low-income areas, the sludge is sometimes disposed of in the open, where it then contaminates surface water and soil. In Bangladesh and West Bengal, India, approximately 19 million people are at risk of arsenic poisoning.

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▲ (left) Case van Genuchten, a researcher at the Geological Survey of Denmark and Greenland, developed a way to separate arsenic from the waste sludge left over after drinking water production. (right) In Bangladesh and West Bengal, India — areas of focus for the study — approximately 19 million people are at risk of arsenic poisoning. Images courtesy of Sebastian Krogh.

“It doesn’t matter where you are in the world, whether it be landfilling or open disposal or something in between, all of the current methods view this waste as a burden,” says Case van Genuchten, a senior researcher at the Geological Survey of Denmark and Greenland...