This paper is an attempt to model the UBC (University of British Columbia) MAP (Magnesium
Ammonium Phosphate) fluidized bed crystallizer. A mathematical model is developed based on
the assumption of perfect size classification of struvitre crystals in the reactor and considering
the movement of liquid phase as a plug flow pattern. The model predicts variation of species
concentration of struvite along the crystal bed height. The species concentrations at two extreme
ends (inlet and outlet) are then used to evaluate the reactor performance. The model predictions
provide a reasonable good fit with the experimental results for both PO4ZP and NH4ZN
removals. Another important aspect of this model is its capability of predicting the crystals size
and the bed voidage at different height of the reactor. Those predictions also match fairly well
with the experimental observations. Therefore, this model can be used as a tool for performance
evaluation of the reactor and can also be extended to optimize the struvite crystallization process
in the UBC MAP reactor.