MILL TRIAL EXPERIENCES WITH XYLANASE - AOX AND CHEMICAL REDUCTIONS - CHLORIDE DIOXIDE CONSUMPTION AND AOX WERE REDUCED

Xylanase mill trials were conducted at Donohue-St-Felicien to identify the potential to reduce bleaching chemical use and lower chloro-organ ic compound formation in effluents and pulps. Using xylanase, the Kapp a factor of the pulp could be reduced from 0.17 to 0.12 to 0.13 while maintaining 90% ISO brightness. This translated to a reduction of appr oximately 5 kg of ClO2 per tonne of pulp. Subsequent vial studies also shelved that xylanase could be used to lower effluent AOX to less tha n 0.25 kg/t. When xylanase was used in an ECF bleaching sequence conta ining peroxide in the extraction stages, pulp OX levels of less than 1 10 ppm could be achieved.