Effect of floc strength on sludge dewatering by vacuum filtration

In this paper, the floc strength requirement of the alum sludge was experimentally investigated for its application on vacuum filtration. Floc strength analysis confirmed that the addition of polymer enforced the floc strength substantially, even in over-dosage, and, therefore, reduced the floc breakage of the alum sludge. The improvement in dewaterability and the minimum floc breakage suggested that floc strength of 5.5 is the optimal condition for vacuum filtration of slum sludge. A diagram is also conducted to demonstrate the application of floc strength depending upon shear stress of the dewatering by vacuum filtration.