Coagulation and flocculation

Coagulation and flocculation are rather inseparable in common industrial wastewater treatment practice. It is rare to find an application where only one or the other is required. In those cases where both processes are not required, it is usually because the missing process already occurs as part of another process. Activated sludge treatment provides such an example where flocculation due to microorganisms producing polysaccharides occurs as an intrinsic part of the biological process. Another example might be a filtration process that needs to coagulate colloidal particles just enough to be of filterable size. Flocculation occurs as the particles travel to the filter or in the filter media.Coagulation and flocculation are much more commonly practiced with industrial wastewaters than with municipal wastewater due to the sheer number and diversity of wastewater matrices that are encountered.The examples here show some of the numerous opportunities to employ coagulation and flocculation on various industrial effluents. These processes can be used both for pretreatment applications before discharge to a municipal sewer or in preparation for direct discharge to a receiving water.