Flocculants & Coagulants

Flocculation

Flocculation is a process where suspended particles are forced to agglomerate through the addition of a clarifying chemical called flocculant. The agglomerated particles formed during the addition of flocculant is typically called ‘flocs’. Once a flocculant is added particle size gradually increases as these ‘flocs’ forms which in turn aids in dewatering by increasing drainage efficiency and solids retention. Initially flocs are quite small and are called microflocs. As these microflocs collide during gentle mixing they bond to produce larger, visible flocs called pinflocs.

To prevent formed flocs from tearing apart or shearing, mixing must remain gentle whilst still allowing sufficient mixing and retention time to allow floc to form and grow.

When utilising a flocculant together with Zebratube® geotextile dewatering bags the flocculant is dosed inline on the delivery side of the pump or dredger. To allow for sufficient mixing and retention time, we recommend the addition of at least four 90 degree bends  or 3 to 4 baffles inside the pipe after the flocculant injection point.

Coagulation

In some applications, a coagulant is used in conjunction with a flocculant to strengthen flocs and to add weight in order to increase the settling rate inside the dewatering bag.