1992 Volume 18 Issue 6 Pages 773-780
Phosphorus removal rate of low phosphate ion concentration by crystallization was investigated using magnesia clinker seed crystals. A decreasing-rate equation of phosphate ion concentration was correlated with second order concerning phosphate ion concentration by a batch shaking method under conditions of constant pH and calcium ion concentration. The rate constant obtained by a batch shaking method was found to be 4.525.11×10-5m3/m2h (mol/m3) at pH=8.28.4 and [Ca] =1.25mol /m3. In addition, the rate constant including variations of solution pH and calciumion concentration was found to be 3.867.44×10-4m3/m2h (mol/m3) 2.5
On the other hand, the rate constant obtained by a packed column method was found to be 4.835.72×10-5m3/m2h (mol/m3) under conditions of pH=8.39.0 and [Ca] =1.25mol/m3. This was nearly equal to that by the batch shaking method.
Furthermore, the decreasing rate in a packed-column experiment using a synthetic feed solution and that in the pilot-scale experiment using secondary effluent were compared. There was highly close relationship between the packed-column experiment and the pilot-scale experiment.
