SEM picture, respective EDS analysis and XRD diffraction spectra of the precipitates (left to right) from batch experiments at 1.5:1 of Mg:P and 45 rpm with (A) MgO; (B) MgCl2 and (C) Mg(OH)2 as Mg2+ sources. Vertical lines (pink) at XRD analysis corresponds to standard struvite (Powder diffraction file (PDF) No. 15-0762). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)