Recovery of nitrogen and phosphorus from human urine using membrane and precipitation process

Surendra K. Pradhan*, Anna Mikola, Helvi Heinonen-Tanski, Riku Vahala

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

32 Citations (Scopus)


The nitrogen (N) and phosphorus (P) contents in human urine have been recovered using struvite precipitation and N-stripping techniques. Struvite precipitation technique recovers mainly phosphorus whereas N-stripping technique only recovers nitrogen. In this study, we developed an NPharvest technique which recovered both nitrogen and phosphorus separately in the same process, enabling their use independently. The technique used Ca(OH)2 to increase the pH of urine converting ammonium into NH3 gas and simultaneously precipitating P with Ca. The NH3 gas is passed through a gas permeable hydrophobic membrane (GPHM) and reacts with H2SO4 forming ammonium sulfate. Our result showed that more than 98% (w/w) of N and P can be harvested from urine in 8 h at 30 °C. The harvested ammonium sulfate contained 19% (w/w) N, and the sediment contained 1–2% (w/w) P. The extraction of N and P from 1 m3 of urine could give a profit of 1.5 €.

Original languageEnglish
Pages (from-to)596-602
Number of pages7
JournalJournal of Environmental Management
Publication statusPublished - 1 Oct 2019
MoE publication typeA1 Journal article-refereed


  • Ammonium sulfate
  • Gas permeable hydrophobic membrane
  • Nitrogen
  • Nutrients recycle
  • Phosphorus
  • Urine


Dive into the research topics of 'Recovery of nitrogen and phosphorus from human urine using membrane and precipitation process'. Together they form a unique fingerprint.

Cite this