Reactor Operation

Fertilizer fabrication in the field

To test the new technologies in the field and ready them for every-day use will be the task of the VUNA research activity "Reactor Operation". The research team in eThekwini will run trials on two nutrient recovery techniques:

Struvite: Often called MAP for magnesium ammonium phosphate (MgNH4PO4·6H2O), struvite is a safe, bio-available and user-friendly fertilizer. Contrary to conventional phosphate fertilizers produced from phosphate rocks – a non-renewable resource, struvite can be precipitated from urine. To tap the abundant nutrients from the urine collected in eThekwini, the VUNA project aims to develop a struvite precipitation reactor, which is easy to operate and yields a maximum of fertilizer. Currently, a reactor is thoroughly tested at the laboratories of the University of KwaZulu-Natal, before the process will be taken to the field. Nitrification and evaporation: In this specific process sequence, the ammonium contained in urine is first stabilized through nitrification, to prevent it from volatilizing. In a second step, evaporation removes the liquid, to produce a solid fertilizer. The nitrification/evaporation process will be tested in eThekwini at a later stage of the project.

Further readings:

• Hug, A., Uder, K.M. (2013) [pdf] Struvite precipitation from urine with electrochemical magnesium dosage. Water Research 47(1), 289-299.

• How to produce fertilizer from urine – Struvite [pdf] – brochure on struvite production
• Struvite from urine in Nepal – featuring manuals for a low-cost struvite reactor
• Growing a healthy future [video] – movie on low-cost struvite production in Kathmandu
  
• Struvite – tool box for sustainable sanitation and water management
  
• Global Phosphorus Research Initiative – resources on phosphorus depletion
• Industrial struvite production: Ostara – Multiform Harvest – NuReSys – SaniPhos