Drying/Fractionation of Deinking Sludge with a High-Velocity Cyclone

Due to the increasing pressure to eradicate solid waste generation, research efforts should be directed toward reducing the volume and increasing the heat value of wastewater treatment sludges with cost-effective and environmentally viable methods. Thus, the potential drying and simultaneous fractionation of deinking sludge was investigated using a high-velocity pilot cyclone dryer. The sludge was processed with an input rate of approximately 500 kg h^-1 leading to an increase in the solid content from 67.9 to 96.3-98.9%, indicating very efficient moisture removal. Although the scanning electron microscope (SEM) images supported the removal of fiber/particle adhesion in the processed samples, the process was not effective enough to separate sludge fibers and mineral particles. Additional fractionation would thus be needed to increase the utilization potential of the dried sludge streams.