A magnesium ammonium phosphate (MAP) crystallization process that works by addition of magnesium seed crystals was used to phosphorus (PO4-P<50g·m-3) removal from side streams from sludge dewatering and thickening processes. Using a bench scale reactor, which consisted of a bubble column with draught and settling tubes, the optimum operational conditions were determined to be: reaction time 2hr, pH 8.9-9.1, molar ratio of Mg/P = 1.0 and an excess of NH4-N, under these conditions the maximum amount of crystallization occurred.
