Talk about making something from nothing: a sewage plant in Japan’s Nagano prefecture recently began mining gold from wastewater. The sewage plant is located in the town of Suwa, where there are “numerous precision machining companies, metal plating facilities and hot springs”, which account for the relatively high concentration of gold in the wastewater that is processed at the plant. The Suwa Construction Office says that approximately 1.9 kg (4.2 lbs) of gold can be mined for every ton of molten fly ash that is generated when incinerating sludge.
That is not a sample of gold from the sludge. But that is gold, and it looks like crap, so. Anyway. The local government already knew about the high concentration of gold in the Suwa sludge as early as 2007, but because the cost of extraction was higher than the price of the gold extracted, they didn’t mine the gold. But since gold commands a higher price nowadays, the Suwa plant began selling the molten fly ash to a smelting plant. Last October they sold 1.4 tons of ash for 5 million yen ($167,000 USD). Not bad at all! The Suwa plant expects to mine a total of 5 tons of ash by March 2009, which should be worth 5 million yen ($167,000 USD). The money will be used to help pay for maintenance and operating costs.
[via Pink Tentacle]