There’s an old adage that ‘one person’s meat is another’s poison’. Well… Japanese researchers have recently confirmed that one company’s effluent may be their fortune.

Engineers at a major Japanese sewage treatment facility say they’ve recovered dramatically higher yields of gold from the sludge they process than those reported by some of the world’s richest gold mines.


Not quite this much recovered in Nagano, yet.

A sewer services official in Nagano, north of Tokyo, postulated that the gold extracted from sewage there in a pilot project probably came from the many precision instrument factories in the area which use a relatively large amount of gold.

The sewage plant reported recovering 1,890 grams of gold per tonne of ash produced by incinerating dried sludge, a byproduct of the plant’s standard waste water treatment process. By comparison, Japan’s most productive gold mine extracts only 20 to 40 grams of gold per tonne of ore it processes.

The Nagano municipal government is expected to bank about (US)$150,000 this year from sales of the recovered gold, less expenses. Of course, the actual amount they receive will depend on the price of gold, which traders expect will, this year, exceed last year’s record of (US)$1,030 per oz.

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