DAF flocculated particles optimum size


In SWRO pretreatment consisting of DAF as a stage, proper size of flocs preceding this stage has been always challenging. On the one hand, coagulants  and flocculants appropriate dosing rate is usually defined using jar test in order that flocs growth is executed to the fullest.

On the other hand, there should be proper relation between the size of particles created in flocculation and the size of air bubbles formed in DAF unit in order to float suspended solids on the surface. In other words, if particles are too large, there might be some difficulties regarding flotation of them using tiny air bubbles. I was wondering if any member of this network has any idea about the issue has had related experiences?