Struvite precipitation in wastewater treatment plants anaerobic digestion supernatants using a magnesium oxide by-product
Magnesium ammonium phosphate
Circular economy
Phosphorus recovery
Wastewater treatment
Low-grade MgO
Magnesium by-product
Issue Date: 
This is an open access article under the CC BY-NC-ND license (
Aguilar-Pozo, V. B.; Chimenos, J. M.; Elduayen-Echave, B. (Beñat); et al. "Struvite precipitation in wastewater treatment plants anaerobic digestion supernatants using a magnesium oxide by-product". Science of the total enviroment. 890, 2023, 164084 - *
Struvite precipitation is a well-known technology to recover and upcycle phosphorus from municipal wastewater as a slow-release fertiliser. However, the economic and environmental costs of struvite precipitation are constrained by using technical-grade reagents as a magnesium source. This research evaluates the feasibility of using a low-grade magnesium oxide (LG-MgO) by-product from the calcination of magnesite as a magnesium source to precipitate struvite from anaerobic digestion supernatants in wastewater treatment plants. Three distinct LG-MgOs were used in this research to capture the inherent variability of this by-product. The MgO content of the LG-MgOs varied from 42 % to 56 %, which governed the reactivity of the by-product. Experimental results showed that dosing LG-MgO at P:Mg molar ratio close to stoichiometry (i.e. 1:1 and 1:2) favoured struvite precipitation, whereas higher molar ratios (i.e. 1:4, 1:6 and 1:8) favoured calcium phosphate precipitation due to the higher calcium concentration and pH. At a P: Mg molar ratio of 1:1 and 1:2, the percentage of phosphate precipitated was 53-72 % and 89-97 %, respectively, depending on the LG-MgO reactivity. A final experiment was performed to examine the composition and morphology of the precipitate obtained under the most favourable conditions, which showed that (i) struvite was the mineral phase with the highest peaks intensity and (ii) struvite was present in two different shapes: hopper and polyhedral. Overall,

Files in This Item:
3.37 MB
Adobe PDF

Statistics and impact
0 citas en
0 citas en

Items in Dadun are protected by copyright, with all rights reserved, unless otherwise indicated.