Laboratory experiments on simultaneous removal of K and P from synthetic and real urine for nutrient recycle by crystallization of magnesium-potassium-phosphate-hexahydrate in a draft tube and baffle reactor

► Mixing speed and HRT affected the crystallization and crystal settlement in the DTBR. ► Mixing speeds of 100-200 rpm and HRTs of 7.5-12.5 h were suggested for the DTBR. ► Slurry should be discharged at a certain CRT to maintain fluidizability in the DTBR. ► 76% K and 68% P were recycled from real urine to solid products using the DTBR.