Feb 03

Mining for Gold in Poop and E-Waste

gold in poopRecently, the topic of mining for gold in poop and e-waste caught my eye. For those who have been following my posts, my finding interest in this idea should come as no surprise, as I frequently write about recycling and the environment, since helping to save our Planet Home is one of my passions. Whether it’s recycling cigarette butts, attacking the plastic plague, adopting green tips when traveling, using poop for power, or offering suggestions on how all of us can help save the world, I enjoy sharing the ideas and hope they are contributing to making a difference.

Gold in e-waste

So I was especially interested in a new report from experts at the University of Saskatchewan who have found an inexpensive way to extract gold from e-waste. Since we are polluting our world and jeopardizing our health and that of other livings things with the 50 million tons of thrown away computers, video games, cell phones, iPads, etc.—80 percent of which end up in landfills–finding an environmentally and financially friendly way to tackle this enormous problem is welcome news. The research team, led by Professor Stephen Foley, noted that the solution they developed also can be recycled and reused, which makes it a win-win-win find.

50 million tons of e-waste is thrown away each year

While gold is a high-priced metal, it also is notoriously difficult to remove or extract from other substances because it is a highly unreactive element. The process of mining gold is destructive because it requires the use of large amounts of sodium cyanide, while the method currently used to extract gold from electronic waste (e.g., computer circuits and chips) is costly and not earth friendly.

This new solution, however, which contains acetic acid, an oxidant, and another acid, can strip gold from e-waste components in about 10 seconds while leaving other metal intact. Another huge advantage of this new solution is that it takes only 100 liters to extract one kilogram of gold, and the solution can be reused again and again. The currently used method requires 5,000 liters of a solution to yield the same amount of gold, and the liquid cannot be reused.

Foley and his team believe their discovery could revolutionize the gold recycling and e-waste industry. I hope this is true. The planet could use a bit of good news.

Gold in poop

Now to a more pungent matter. Did you know there is likely gold in your poop? Human waste is part of the biosolids system that also harbors silver and other metals as well as rare elements such as vanadium and palladium. This fact makes poop and biosolids in general a valuable commodity, and some researchers are trying to find out exactly how much money we are flushing away and how to recover it. It’s a smelly job, but thankfully some people are happy to do it.

mining for gold in poop and e-waste

Mining for gold in poop and e-waste

Gold and other metals that enter wastewater and solid waste systems come from e-waste, cosmetics, health care products, household cleaners and detergents, medical waste, and other sources. Regardless of their origin, the metals typically end up in our wastewater treatment facilities and in leftover solid waste.

After wastewater is processed at treatment plants, the end products are treated water and biosolids. Of the estimated 7 million tons of biosolids produced by wastewater facilities in the US every year, about half find their way to forests and fields as fertilizer (those that have been cleared of regulated metals, which limit their use on soil), and the rest ends up in landfills or incinerators.

Some experts, including Kathleen Smith, PhD, who talked about her team’s exploration at the 249th National Meeting & Exposition of the American Chemical Society in March 2015, are attempting to identify and learn how to effectively and safely collect metals such as gold, silver, and copper from biosolids. Thus far they have found microscopic mineral deposits that are sufficient to be economically viable. Since money talks, this finding could be great news for the environment as well as a financial boon.

The authors of another 2015 research paper calculated that the biosolids from 1 million Americans could be hiding as much as $13 million in metals. When you consider the population of the US is more than 300 million…well, you can do the math!

Mining for gold in poop and e-waste looks like a win-win endeavor for the planet if sustainable methods are used. One man’s waste is another man’s treasure.


Newswise: Yes, poop could be a source of valuable metals and critical elements

Newswise: Turning electronic waste into gold

Westerhoff P et al. Characterization, recovery opportunities, and valuation of metals in municipal sludges from US wastewater treatment plants nationwide. Environmental Science and Technology 2015; 49(16): 9479-88


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