Experimental analysis of floc size distributions in a 1-L jar under different hydrodynamics and physicochemical conditions.

This study focuses on the relation among hydrodynamics, physicochemical conditions, and floc size. During ortho-kinetic flocculation, the floc size is controlled by a balance between hydrodynamic stress and aggregate strength. Special attention was paid to the influence of a hydrodynamic sequencing on both the aggregate strength and the flocculation processes. Experimental research was conducted in a 1-L jar for two different pH values. The hydrodynamic sequencing was made up of successive slow and rapid mixing periods, and different slow mixing intensities were studied. First, the large floc size was shown to decrease with increasing velocity gradient (G), with an expected trend (d proportional variant epsilon(-1/4)). Then, the aggregate strength was shown to depend on two main factors: the flocculation history and the physicochemical conditions, which control the cohesion forces between primary particles. Finally, flocculation processes are discussed in terms of aggregation and breakup phenomena, with relation to local hydrodynamics and physicochemical conditions.

Hydrodinamics and mass transfer in ozonation reactors: use of CDF modelling

El diseño del proceso de desinfeccion del agua debe descansar en los fundamentos de la ingenieria quimica considerando los aspectos cineticos e hidrodinamicos. El objetivo del trabajo es brindar un panorama de la capacidad de las herramientas del CDF (un modelo de ecuaciones de movimiento de fluidos utilizando sistemas de computacion) para explicar los fenomenos fisicos y quimicos que tienen lugar en los distintos reactores para la ozonizacion. El diseño y el control de las condiciones optimas es de importancia fundamental para lograr la mayor eficiencia del proceso. Se explican las aplicaciones del modelo para la cloracion y la ozonizacion