EFFECT OF WOOD SPECIES ON THE ENVIRONMENTAL-QUALITY OF LABORATORY-PREPARED TCF PULP BLEACHING EFFLUENTS

Several peroxide-based bleaching effluents (i.e., QP) were prepared in the laboratory using oxygen-delignified kraft pulp derived from Dougl as fir, hemlock, cedar and a spruce/pine/fir mixture in order to deter mine the effect of wood species on the environmental quality of totall y chlorine-free (TCF) bleaching effluents. The relative environmental quality of the bleaching effluents was assessed using acute lethal (Ce riodaphnia, Daphnia magna and Microtox) and chronic sublethal (Cerioda phnia reproduction) toxicity tests. The QP bleaching effluents were ob served to exhibit relatively high chronic toxicities to Ceriodaphnia i n comparison with D(100)Eop bleaching effluent, regardless of the wood species employed. In terms of laboratory versus mill comparisons. the D(100)Eop bleaching effluents had ver similar toxicological propertie s, indicating that laboratory-prepared effluents can adequately simula te the environmental effects of mill bleach plant effluents for chlori ne dioxide based sequences.