Call it “dirty money” if you wish, because there’s about CHF 3 million in gold and silver found each year in Swiss sewage.
But no one is going to get rich, according to a just-published report by the Swiss Federal Institute of Aquatic Science and Technology (Eawag).
Recovering the estimated CHF 1.5 million in gold, and the same in silver, that passes through Swiss wastewater each year, wouldn’t be cost-effective, says the report. On the bright side, the concentrations measured pose no environmental or health threat.
These precious metals don’t come from jewelry thrown down the toilet by jilted lovers. Rather, they are among numerous trace elements used increasingly in high-tech and medical industries. Other metals include gadolinium (used in luminous paints) and niobium (used in alloys and coatings), plus other exotic-sounding metals like ytterbium (an alloy in stainless steel) and neodymium (an alloy in magnets).
The study – the first of its kind in Switzerland – was conducted at 64 wastewater treatment plants around the country, and was commissioned by the Federal Office for the Environment. The amount of a given metal varied widely from plant to plant. Overall, during a year of study, 43 kg of gold were recovered and 3,000 kg of silver.
There’s little data to track where all this flushed-away gold, silver and other precious metals end up, but they certainly won’t be in a bracelet. What a waste.
By Bill Harby