Potassium struvite precipitation

recovery of potassium and phosphorus from a liquid effluent in the form of magnesium potassium phosphate (MPP or K-struvite)

Liquid streams rich in denitrified P, products of other processes

Mg2+, K+ and PO43- ions will combine in an equimolar ratio to form K-struvite. Given the decompensation that usually exists in the water to be treated between the concentration of P and K, P being the limiting element, recovery efficiencies will be higher for P than for K (e.g. 93% P and 10 % K at pH 11.5 for NDN effluent in pig slurry treatment)

It is necessary to work at a high pH value;
The process is negatively affected by the presence of Ca2+ or NH4+ ions in the medium;