AWWA WQTC52964

Up to now, most of the models developed for the coagulation-flocculation processhave been based on empirical relationships or based on stochastic approaches fordata acquisition interpretation. Due to the complexity of the system, nodeterministic models are available. This work is based on experimental analysisof both floc size distribution and local hydrodynamics in a jar test vessel. Inthe study, pH and both the type and dose of coagulant were fixed. The temporalevolution of the floc size distributions were determined from a statisticalanalysis of the experimental data. It leads to basic information on agglomerationkinetics. The statistical analysis of the velocity field enables thedetermination of the mean velocity field and the magnitude of the mean velocitygradients. However, it is interesting to consider instantaneous velocity fieldsand the associated instantaneous velocity gradients. The results presented hereare the very first results of a more general study. It highlights the closerelationship between the characteristic size of the flocs and the local dissipationrate of turbulence that can also be expressed in terms of velocity gradient. Includes 8 references, table, figures.