Technical Bulletin No. 0261: Effect of Bark Addition on the Dewatering Properties of Biological Sludges

One of the principal problems associated with activated sludge treatment of mill effluents concerns the dewatering for disposal of excess biological cell solids generated during oxidation of organic constituents. By themselves such sludges are extremely difficult to dewater even when conditioned with inorganic coagulants or organic polyelectrolytes. When mixed with primary sludges successful dewatering is a function of the ratio between primary and secondary sludges present and the amount of long-fibred material in the primary sludge.