EAWAG Aquatic Research in Switzerland has been working with UN Habitat to devise low cost ways to make bio-available fertilizers from Urine. Their method involves precipitating out solid Struvite (~MgNH4PO4·6H2O) by adding Magnesium to raw urine. This method seems to be promising and requires no complex machinery or electricity.
The big challenges appear to include sourcing of a Magnesium feedstock and making it cost effective/competitive. In this pilot project UN Habitat got it from a salt manufacturing plant in India but clearly there must be other solutions found to make this a replicable decentralizable project (they had issues transporting the salt brine across the border too). Apparently, selling this product at the market value would not necessarily lead to recovered costs and eventually profit. The researchers working on this project suggest that the costs of environmental issues like waste diversion and decentralized production be taken into account but I’m not sure how that will happen…
Here is a link to an informative poster about this pilot project
how it is done
Andrew
waterlady
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