P removal from anaerobic supernatants by struvite crystallization: long term validation and process modelling

In this work, a model for phosphorus crystallization in a fluidized bed reactor, able to describe the experimental results obtained during a semiscale pilot plant, is presented. In particular, the validity of the model proposed has been evenly extended with respect to a previous experiment, even at a lower contact time, and the length of each experiment has been increased, in order to verify the behaviour of the process for long term applications and to evaluate the maximum crystal growth of the system. Moreover, the state of the art of the available processes for phosphorus removal from wastewater is presented, together with a detailed review of the several models so far developed to describe the phosphorus crystallization mechanisms.