Potential drying/fractionation of primary paper mill sludge.

To reduce the volume and increase the heat value of wastewater treatment sludges, economically and environmentally viable methods for increasing the total solids content of the materials are of key concern. Thus, potential drying and fiber/mineral -fractionation of primary paper mill sludge was investigated with a high velocity pilot cyclone. The sludge was processed with an input rate of approx. 500 kg/h leading to an increase in the dry matter content value from 49.5% to 89.6 - 98.6%. Based on the loss-on-ignition data, the fiber/mineral -fractionation of the input sample proved relatively inefficient with a minor increase in the organics content from 33.0 to 44.5%. However, acquired SEM images indicate removal of fiber/particle -adhesion in the processed samples. Elemental analysis suggests possible enrichment of especially Cu, Fe, Mn, Ni, Zn, P, and alkalis in the processed samples most likely due to the processing conditions and fraction collection arrangements of the pilot plant. Additional optimization of process conditions could generate more efficient fiber/mineral -fractionation thus confirming the need for further optimized pilot testing. [ABSTRACT FROM AUTHOR]