Significant improvements in ECF bleaching using a minimal capital approachto better filtrate management - Lowering bleaching costs through modified filtrate recycling

Western Pulp's Squamish Operation produces fully bleached softwood market k raft pulp using a [D(EO)] (EOP) D bleaching sequence. The mill utilizes dis placement bleaching towers and diffusion washers. Since June, 1999, bleachi ng costs have been lowered by 7-9%, depending on the grade produced, throug h modified filtrate recycling. Simultaneously, final pulp brightness has in creased while pulp TOX content has decreased. The success that the mill has realized was obtained using minimum capital expenditure, achieving a payba ck period of less than 30 days.