The sewage treatment plant at Suwa, Nagano Prefecture, Japan is a modern day urban mine. The plant extracts more than 4 pounds of gold from each ton of the fly ash that it produces from processing wastewater.
The Suwa Basin is home to mineral springs as well as to precision machining companies and metal plating facilities. All of these are thought to contribute to the high concentration of gold in the wastewater sludge.
The sewage treatment plant yields about 12.4 lbs of gold per day. That’s a whopping 4600 lbs per year and will net the processing company, Nagano Prefecture Suwa Construction Office, a hefty annual bonus.
Key Themes Behind This Trend
- Urban Mining
- There is an opportunity to extract valuable metals and minerals from wastewater sludge through urban mining processes.
- Circular Economy
- Extracting valuable resources from industrial waste and repurposing them for other uses can result in a more sustainable and circular economy.
- Waste-to-value
- Turning sewage waste into a valuable resource like gold demonstrates the potential for waste-to-value innovations in the future.
Where This Applies
- Mining
- The mining industry can explore urban mining operations as a new source for gold and other valuable minerals.
- Waste Management
- Waste management companies can incorporate wastewater sludge processing as a potential source for extracting valuable materials and reducing waste.
- Construction
- The construction industry can explore opportunities for urban mining and extracting valuable minerals from industrial waste in their operations.
