America's collective human waste contains millions of dollars worth of energy, water, and even rare and valuable metals like gold and palladium. The question is: How do we extract it?

Image Credit: Heather Lowers, USGS Denver Microbeam Laboratory

At Popular Science, Mary Beth Griggs reports on the work of USGS researcher Kathleen Smith, which she will present this week at the 249th National Meeting & Exposition of the American Chemical Society (ACS) :

A study published in Environmental Science and Technology earlier this year found that the waste from 1 million Americans might contain metal (including gold, silver, titanium, lead, and zinc) worth up to $13 million. With nearly 320 million people living in the United States, that's a substantial goldmine—if scientists can figure out how sift the valuables from the sludge.

Kathleen Smith from the U.S. Geological Survey is working with several cities to analyze the solid waste for precious metals, to see exactly how much and what kinds of metals might be found at wastewater treatment plants. In some places, the concentration of gold is about the same as the amount found in a natural mineral deposit.

Precious metal isn't the only thing hiding in human waste. Recently, researchers have been dipping into sewer systems in search of drugs, and the Janicki Omniprocessor turns human waste in sewer sludge into drinking water and electricity.

For more on the reclamation potential of human sewage, and the wonders of waste in general, I highly recommend "Wasteland," the outstanding Harper's essay by Frederick Kaufman.


Contact the author at rtgonzalez@io9.com.