AWWA JAW28412

Fluid motion in an oscillating-grid flocculator was investigated quantitatively with a laser Doppler velocimeter for two mixing conditions. Batch flocculation experiments were performed for monodisperse, bimodal, and trimodal latex suspensions. The effects of mixing intensity, particle charge, and suspension concentration on the rate of change in particle size distributions were studied. Experimental results indicated that large eddies are relatively unimportant for flocculation and that flocculation is induced by eddies of approximately the same size as the particles. A method for estimating the velocity gradients in eddies of different sizes in the flow was developed and incorporated into an existing mathematical model for flocculation. The predictions of the revised flocculation model were compared with the experimental results and indicated that the velocity gradients of the eddies adequately describe the interparticle contacts resulting from mixing during flocculation. Includes 21 references, table, figures.

Product Details

Edition:

Vol. 82 - No. 8

Published:

08/01/1990

Number of Pages:

15

File Size:

1 file , 2.4 MB