Abstract

In urine-separating sanitation systems, bacterial urease enzymes can hydrolyse urea to ammonia during the pipe transport and storage of urine. The present study investigated whether it was possible to reduce the urine volume without losing the nitrogen as ammonia. A method for stabilising the urine prior to dehydration was developed. Briefly, fresh human urine was stabilised by passage through an anion-exchanger, added to an alkaline media (wood ash or alkalised biochar), and dehydrated. Urine dehydration was investigated at three temperatures: 40, 45 and 50 degrees C. The influence of various factors affecting the dehydration process was modelled and the rate of urine dehydration was optimised. Results indicated that 75% (v/v) of the urine has to pass through the ion exchanger for alkaline stabilisation of urine to occur. At all investigated temperatures, the dehydrator accomplished >90% volume reduction of ion exchanged urine, > 70% N retention and 100% recovery of P and K. To realise high degree of nutrient valorisation, this study proposes combining source separation of human urine with alkaline dehydration. (C) 2018 The Authors. Published by Elsevier Ltd.

Keywords

Decentralised sanitation; Ion-exchange; Response surface optimisation; Urease; Urea stabilisation; Urine dehydration

Published in

Water Research
2018, Volume: 142, pages: 325-336
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Simha, Prithvi

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    
  • Central European University

• Senecal-Smith, Jenna

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Nordin, Annika

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Lalander, Cecilia

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Vinnerås, Björn

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Water Treatment


Publication identifier

DOI: https://doi.org/10.1016/j.watres.2018.06.001

Permanent link to this page (URI)

https://res.slu.se/id/publ/96235