Possibilities of the numerical treatment of images to assess quantitatively the morphological characters of flocs

This paper presents the capabilities of the digital image processing in the coagulation-flocculation process. By coupling a photographic technic with the digital processing, it is possible to access quantitatively the morphological characters of flocs. We have studied the floc formation during the rapid mixing step. The influences of chemical nature and reaction type of the coagulants where studied in order to analyse the size differencies of microflocs. The result obtained show that: • ⊎ Size and shape of microflocs are well defined at the optimum of flocculation. But if the floc shape is fixed before the optimum of flocculation, the flocs size is maximum only when the efficiency of flocculation is maximum; • ⊎ There are differencies in the floc size for the three coagulants used. These differencies are due to the nature and the action mechanism of the coagulant used.