University of Oulu

Tuomikoski, S., Sauvola, E., Riponiemi, M., Lassi, U. & Pesonen, J. (2023) Usage of phosphoric acid plant's circulate pond waters in struvite precipitation—Effect of conditions. Water and Environment Journal, 37(3), 445–453. Available from:

Usage of phosphoric acid plant’s circulate pond waters in struvite precipitation : effect of conditions

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Author: Tuomikoski, Sari1; Sauvola, Emilia1; Riponiemi, Marko2;
Organizations: 1Research Unit of Sustainable Chemistry, University of Oulu, Oulu, Finland
2Yara, Siilinjärvi, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
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Language: English
Published: John Wiley & Sons, 2023
Publish Date: 2023-01-30


Struvite is a suitable fertilizer, and electrochemical precipitation of nutrients from industrial waters provides one answer to the circular economy. Molar ratio between ammonium and phosphate is crucial: Water suitable for the precipitation includes more or at least the same amount ammonium than phosphate. That kind of water typically does not exist in industry. Therefore, ammonium-rich industrial water was mixed with phosphorus-rich water to obtain a suitable molar ratio for struvite precipitation. Parameters were studied to determine their effect on removal-% and struvite yield. 100% struvite yield was obtained under several conditions even without pH control with pH 7–9. The highest phosphate removal (99.7%) was occurred with the molar ratio 1.7:2:1 for Mg:NH₄:PO₄ (pH 9.0). Waters dilution prevents magnesium anode corrosion. Formed struvite has potential as recycled fertilizer due to low bioavailability of metals and high leachability of nutrients studied by four-stage sequential leaching.

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Series: Water and environment journal
ISSN: 1747-6585
ISSN-E: 1747-6593
ISSN-L: 1747-6585
Volume: 37
Issue: 3
Pages: 445 - 453
DOI: 10.1111/wej.12848
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: This work was conducted under the auspices of the Waterpro (ERDF project number: A74635, funded by the European Union, European Regional Development Fund, Leverage from the EU Central and Ostrobothnia Regional Council) and the project “Reaching congenial region through valorisation of municipal and industrial wastewaters and sludge” (Waste Recycling, KA4020) funded by the Karelia CBC Program.
Copyright information: © 2023 The Authors. Water and Environment Journal published by John Wiley & Sons Ltd on behalf of CIWEM. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.