ABSTRACT
The degradation of high molecular weight (HMW) chlorinated organic material isolated from bleached kraft mill final effluent was studied using fungal strains and sunlight. Naturally occurring fungi, isolated from river biofilms, wood, and sediment samples, and two white-rot fungi, Trametes versicolor and Phanerochaete chrysosporium, were capable of degrading the HMW fraction of bleached kraft mill effluents, resulting in reductions in effluent color, adsorbable organic halogen (AOX), and molecular weight. Size distribution analysis indicated that both high and low molecular weight materials were degraded equally. Photolysis experiments revealed that filter-sterilized HMW material could be photodegraded under natural sunlight conditions, resulting in substantial losses in AOX, color, and molecular weight. Half-lives for AOX mineralization and decolorization were estimated at 10 and 21 d, respectively, during fall months. Irradiation also resulted in the release of chlorinated guaiacols and vanillins. Pretreatment of HMW chlorinated organic material with sunlight did not enhance subsequent fungal degradation.
