Scientists at the Swiss Federal Institute of Aquatic Science and Technology, or Eawag Aquatic Research, estimated that about 43kg of gold, worth B51mn (about US$1.8mn) passes through the country’s sewage system every year, said the report posted by the institute. (See report here).
The estimate comes after studying 64 water treatment plants in Switzerland, concluding that at certain sites in Ticino region, concentrations of gold in the wastewater are “sufficiently high for recovery to be potentially worthwhile.”
“This can be attributed to the presence of several gold refineries in the region,” said the report.
“Overall, however, according to the researchers, the recovery of metals from wastewater or sludge is scarcely worthwhile at present,” they added.
The study also estimated about 3,000kg of silver, 1,070 kg of gadolinium, 1,500kg of neodymium and 150kg of ytterbium going to waste, mostly residue from the chemical and medical industries.
Around 70% of the world’s gold passes through the country’s refineries on average every year, and the large amounts of gold can be attributed to this and the watch making industry, explained the report.