BIOMASS PHOTOCHEMISTRY-XXII - COMBINED PHOTOCHEMICAL AND BIOLOGICAL PROCESS FOR TREATMENT OF KRAFT E1 EFFLUENT

The photocatalytic conditions for decontamination of Kraft effluents f rom Eucalyptus grandis (Brazil) and Pinus radiata (Chile) were studied . Irradiation in the presence of ZnO was similar for E. grandis and P. radiata effluents reaching a total decolorization after 2 h. This cor relates with the mineralization process. When ZnO was immobilized on s and a two-fold faster decolorization was observed after 30 min of irra diation. The combined photochemical-biobleaching process was effective in the decolorization of Eucalyptus Kraft El effluent. By applying a short time of irradiation (10 min) the time necessary for 50% of biolo gical colour reduction was decreased to half. The contribution of the photochemical process when applied as a posttreatment was least eviden t. In this case additional reduction of about 10% on the AOX content a nd almost completion of the decolorization process was observed for Pi nus Kraft El effluent. Photochemistry applied to pulp and paper indust ry appeared as an important technique to remediate pollution problems. (C) 1998 Elsevier Science B.V.