Treasure hunters spend their lives looking for valuable objects like gold coins and silver ornaments in shipwrecks or archaeological sites, often involving dangerous stunts. But tonnes of precious metals are actually hiding in plain site, right where you wouldn’t expect them: in your faeces.
Many products we use in our day-to-day life, like shampoos and detergents, contain precious metals, which gather up in urban pipes. Or they can be found in the food and drink we consume and that, after a while, accumulates in our body until is removed by excretion, which also ends up in the sewage drains. So imagine if this process was carried out by thousands of people, all living together in a city. The amount of valuable elements in the sewage would be outstanding! And so has been confirmed in a study by the US Geological Survey that found out that the concentration of precious metals in a city’s sewage system is comparable to that in an actual working mine.
For example, in a single kilogram of ‘sewage slime’, you can find 0.4mg of gold and 28mg of silver, metals used in jewellery; 638mg of copper, a metal used in electrical wiring and 49mg of vanadium, which has important industrial applications. But in the larger scale of a whole city, it has been calculated that by all these metals being thrown into the sewers, up to £510 million a year are being lost in the UK.
In an attempt to profit from this waste, companies are starting to consider human faeces as a viable source of precious metals. It’d be quite a profitable venture for them, and much greener than traditional mining since instead of using hazardous chemicals in lands where they can contaminate a habitat, they are used in an enclosed factory. And although working with faeces sounds like an outrageous idea and a bad time, it has been done for many years now, as it is used to make plant fertilizers.
As a fortunate side effect, we would actually be making our excrements cleaner and therefore protecting the environment. Faeces not only contain gold and silver, but heavier metals like lead which can be toxic to an ecosystem. By processing our waste, we’d make sure that not only the valuable metals are removed, but the harmful ones too. This idea just gets better and better!
So who knows, maybe someday in the near future you will wear gold bracelets that come from your faeces, or phones with microchips made of components of our waste.