Scientists claim that human excrement could be worth a fortune, after they identified valuable minerals in poo - including gold. Researchers in the US were examining sludge from sewage treatment plants, and said that if the levels of minerals they found had been identified in rocks, they would have been classed as commercially viable for mining.
At a meeting of the American Chemical Society, Kathleen Smith of the US Geological Survey highlighted that as well as gold, the waste also included copper, palladium and vanadium. She explained that precious metals are used in everyday products, including shampoo and detergents, which eventually find their way into waste.
She argued that not only would it pay to extract the minerals from the waste, it would also reduce the release of harmful metals into the environment, and reduce the amount of toxic sewage that is incinerated. According to The Guardian, she said: "If you can get rid of some of the nuisance metals that currently limit how much of these biosolids we can use on fields and forests, and at the same time recover valuable metals and other elements, that's a win-win."
This isn't the first time that valuable minerals have been found in human waste. A US Geological Survey study in 1978 examined the ashes of incinerated human waste in California, and said they had identified large quantities of silver, gold, and copper. They estimated that in the 900 metric tons of ash in the city dump there was around $2.5 million worth of minerals. They calculated that the ash could yield £0.5 million of minerals a year, and concluded it was "an attractive opportunity for the profitable recovery of a number of mineral resources."
Since then, demand for these minerals has increased exponentially, as many of them are used extensively in manufacturing technology. It means that mining human excrement could be even more rewarding now. The BBC reported that in January this year, an Arizona State University study concluded that around $13 million of minerals could extracted from waste each year.
And while it may sound impossible, a sewage treatment faulty in Tokyo has already started extracting gold from sewage sludge. In 2009 The Telegraph reported that yields at the plant were higher than some commercial mines. At the time, it also highlighted that waste in this area was likely to be particularly valuable because of the high concentration of equipment manufacturers using gold in the region.
The newest study took samples from a number of areas, and found high concentrations of the minerals throughout, which could mean these kinds of plants are worth opening elsewhere. The question is whether it would make these precious metals any less desirable if we knew where it might have come from.
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