Simultaneous recovery of phosphorus and potassium as magnesium potassium phosphate from synthetic sewage sludge effluent.

Author(s) Nakao, S.; Nishio, T.; Kanjo, Y.
Journal Environ Technol
Date Published 2017 Oct

Bench-scale experiments were performed to investigate simultaneous recovery of phosphorus and potassium from synthetic sewage sludge effluent as crystals of magnesium potassium phosphate (MPP or struvite-(K), MgKPO4·6H2O). The optimal pH of MPP formation was 11.5. A phosphorus level of at least 3 mM and K:P molar ratio over 3 were necessary to form MPP, which showed higher content rate of phosphorus and potassium in precipitate. MPP crystallization was confirmed by analysing the precipitates using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) apparatus and an X-ray Diffractometer (XRD). Inhibition of MPP crystallization by iron and aluminium was confirmed by precipitation experiments and SEM-EDX analysis. Potassium ratio against magnesium in precipitate decreased for iron concentrations greater than over 0.2 mM and aluminium concentrations over 0.05 mM.

DOI 10.1080/09593330.2016.1264485
ISSN 0959-3330
Citation Environ Technol. 2017;38(19):24162426.

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