Obtenção dos parâmetros cinéticos da floculação com utilização de técnica de análise por imagem

Abstract

The purpose of this work was to evaluate the influence of first class particles in flocculation monitoring, simulated on Jartest stand equipment for low turbidity water using aluminum sulfate, ferric chloride and aluminum polychloride as coagulants. To follow the flocculation and obtain the particle size distribution curves (DTP) and their representative parameters, the technique of image analysis of the flocs obtained by digital camera from the laser light plane was used. The DTP was distributed in 16 size classes, being the first class, considered in the premise of this work, as representative of the primary particles. To evaluate the influence of first-class particles on flocculation performance, different values of mean velocity gradient (G) (20, 30, 40 and 80 s-1) were investigated for different flocculation times. The results obtained were evaluated based on the kinetics of flocculation by means of the aggregation constants (KA) and rupture (KB) and in the DTP, having as control parameter the average diameter of the flocs. In general, it was observed that with the increase of G there was a decrease in the flocculation efficiency and that the tendency of equilibrium between KA and KB occurred in the first minutes of the process. The values of KA and KB founded are very similar to those obtained using the classical methodology which considers remaining turbidity for indirect measurement of flocculation efficiency, therefore, the use of the number of particles of the first size class may be appropriate.