Influence of Residual Black Liquor in Pulp on Wastewater Pollution after Bleaching Process

Abstract

The influence of residual black liquor in pulp on wastewater pollution after the bleaching process was studied. The results show that the CODCr in bleaching effluent has a remarkable linearity with bleaching loss of pulps without residual black liquor. For pulps with some residual black liquor, more than 34% of the overall CODCr is produced by the residual black liquor. It follows that more effective washing to reduce the residual black liquor is an appropriate way to control the pollutant discharges from pulp and paper mill industry.