How Valuable Is Switzerland’s Sewage?

About 70 percent of the world's gold is processed annually at Swiss refineries, and new research indicates that some of the precious metal ends up at the country’s 64 wastewater treatment plants. After taking widespread sewage samples, researchers at the Swiss Federal Institute of Aquatic Science and Technology determined that about 95 pounds (43 kg) of gold -- worth about $1.8 million USD -- are flushed down the drain each year. It’s believed that tiny flecks of discarded gold come from the country’s many watchmaking operations and gold refineries.

Flush with precious metals:

• Scientists say it would be too costly to extract gold from sewer sludge, except in areas like the southern Ticino region, where there is a high concentration of gold refineries.
• Researchers also found more than 6,500 pounds (2,948 kg) of silver and rare earth minerals in Swiss sewers, linked to the manufacture of electronic devices.
• The research findings were published in the journal Environmental Science and Technology.