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Mining Sewage

April 6, 2015

Is sewage worth mining for gold?



Heather Lowers USGS Denver Microbeam Laboratory

Microscopic gold-rich and lead-rich particles in a municipal biosolids sample.(Heather Lowers/USGS Denver Microbeam Laboratory)

There’s gold in that thar sewage! I’m Bob Hirshon and this is Science Update.

There’s silver, gold and platinum in treated human waste, and scientists at the annual meeting of the American Chemical Society presented evidence that it may be worth mining. Research geologist Kathleen Smith at the US Geological Survey says that the source of these metals is unclear.

KATHLEEN SMITH (US Geological Survey):

And the biosolids and sewage sludge itself contain a lot more things than human waste. And it’s pretty much the possibility of anything that goes down the drain: so, things from the washing machine, or the dishwasher, or the shower, are all things that go down the drain.


The total amounts of the minerals are impressive. But whether they can be profitably extracted isn’t yet known; the work is aimed at looking for new sources of minerals to offset our dependence on traditional sources and imports. I’m Bob Hirshon, for AAAS, the science society.