Physicochemical clarification treatments
Wastewater is considered dispersions due to the large amount of impurities it contains in suspension. The size of these impurities varies widely. The separation of a large part of the impurities is effected by sedimentation, however, as many of the impurities are too small, it is necessary to agglutinate these particles into larger aggregates that are more easily decanted.
This aggregate-forming process is generically referred to as coagulation. The process of coagulation and flocculation through the use of chemical treatments, combined with a physical process of solid-liquid separation, constitutes the solution called physico-chemical treatment. In this separation phase, there are two common solutions: decanting or floating, the latter being the most widespread for use as primary treatment in treatment plants.
A DAF dissolved air flotation system is a system that separates suspended particles through microbubbles of air in a supersaturated solution. The solids adhere to the microbubbles on their upward path and float toward the upper separation system.