Treatment of Selected Internal Kraft Mill Wastes in a Cooling Tower

Cooling of pulp mill condensates, decker filtrate, turpentine decanter underflow and condenser waters from a barometric type evaporator produced the removal of 10,000 lbs BOD per day and an 8 to 10 mgd reduction in overall mill water needs for an 850 ton/day Kraft linerboard mill. The 25% to 30% BOD reduction is attributed to physical stripping of volatile components. No significant operational problems have occurred, and preliminary treatability studies have indicated that the cooling tower blowdown does not adversely affect biological treatment processes. Costs and savings are mentioned.