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You’re flushing a goldmine down the toilet, literally

At a recent meeting of the of the American Chemical Society, researchers proposed a novel source of valuable metals: waste water. They proposed a method that could be used to extract valuable metals like gold, silver or titanium which end up in waste water plants via the city’s sewage, according to an article in ZME Science.

According to Kathleen Smith of the U.S. Geological Survey (USGS), more than 7 million tons of biosolids come out of U.S. wastewater facilities each year. Half of that is used as fertilizer, while the rest is sent to landfills or is incinerated. One man’s trash, is another’s treasure, and with this in mind Smith and colleagues are currently working on ways to value solid waste, particularly rare metals.

So far, Smith’s group has collected samples from small towns in the Rocky Mountains, rural communities and big cities. They found traces of platinum, silver and gold, and on a case by case basis, these could be found in a high enough concentration for extraction to become economically feasible.

Elsewhere, the city of Suwa in Japan is already working on extracting the gold from its sewers. They installed a treatment plant near a large number of precision equipment manufacturers reportedly collected nearly 2 kilograms of gold in every metric ton of ash left from burning sludge, making it more gold-rich than the ore in many mines.

Read the entire article from 23 March on ZME Science’s website

Energiaskor 2015-03-31


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