NPR

There's Gold In Them Thar Sewage Pipes, Swiss Researchers Say

Each year, more than $3 million in gold and silver winds up in Swiss wastewater, scientists found. But in most cases, it doesn't make economic sense to extract and recycle the metals.
Researchers collect a sample at the Werdhölzli wastewater treatment plant in Zurich, as part of an Eawag research project exploring the concentration of various metals in treated wastewater.

In Ticino, Switzerland, the streets aren't paved with gold. But the sewage pipes are packed with it.

And across the country as a whole, some $3 million worth of gold and silver is thrown out in wastewater every year.

That is who evaluated 64 municipal wastewater treatment plants across the country. Scientists have long known that small amounts of the valuable metals can wind up mixed in with sewage. In Switzerland, the researchers found, the small quantities add up — to more than 6,600 pounds of silver and nearly 100 pounds of gold, the researchers estimate.

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