The recently developed mechanically stirring fluidized bed reactor is used with notable success in France for the precipitation of many compounds in pilot, semi-industrial and industrial scales. The aim of the work is to study the feasibility of the phosphorous recuperation in the form of struvite by precipitation in this reactor. The experiments carried out in a pilot plant with synthetic solutions show that high treatment capacity and high recuperation yield from 97 to 98% can be attained. The functioning of the reactor is very stable for weeks without sophisticated controlling systems. In addition, the precipitate is easily filterable and washable, and has a mean particle size up to 170 gm. The results are used to determine the maximum treatment capacity of the mechanically stirring fluidized bed reactor in the case of struvite in order to extrapolate it for industrial applications.