Synthetic swine wastewater (manure) was treated with soln. of MgCl2 and NaOH at 298 K and pH 9 for 3600 s to ppt. phosphate(V) ions as sparingly soluble amorphous Ca phosphate(V) (76.5% by mass) and struvite (21.9% by mass). The solid product contained some impurities (metal hydroxides). Size of solid particles did not exceed 64 pm. Their mean size was 15.5 mu m. Homogeneity within the population of product particles was moderate with large agglomeration effects.