In the latest article published in Science of the Total Environment (STOTEN), Prithvi Simha and colleagues (Chibambila Simbeye, Caitlin Courtney, and Nico Fischer) show for the first time that we can produce vivianite from human urine. For those who don’t know, vivianite is iron phosphate ((Fe(II)3(PO4)3·8H2O) and is in high demand in the electronics industry for lithium-ion battery production as well as in the art industry as a pigment in paint. It can be sold for as much as $100-500 per kg. Considering that struvite and calcium phosphate can typically only be sold for $1 kg−1, recovering P as vivianite would likely be significantly more profitable.
In this work we determined ideal operating regions for vivianite production from human urine. We showed that overdosing iron exerted a competitive effect that suppressed the precipitation of other precipitates and could also compensate for changing urine compositions. Overall, the highest yield and purity was 93% and 79% respectively. We showed that the presence of organics in real urine ultimately affected the purity. Thank you to the Water Research Commission for funding this work and to the SLU – Swedish University of Agricultural Sciences‘s August T Larsson Guest Research program for Dyllon’s current research visit to SLU.