SEQUENTIAL TREATMENT OF E1 STAGE KRAFT BLEACH PLANT EFFLUENT

The effluent discharge from a kraft bleach plant contains large amount s of chlorinated organics. These chlorinated organics, termed chloroli gnins, are produced by chlorine addition to residual lignin in the unb leached pulp. They can be problematic in the environment, and the pape r industry would prefer they not be discharged. However, effective mea ns to destroy chlorinated organics from the bleach plant have not been developed. The objective of this study was to evaluate two flowsheets for the destruction of these chlorinated organics. The first flowshee t consisted of an RBC, on which a white rot fungus had been immobilize d, followed by an anaerobic digester. The second flowsheet consisted o f an aerated lagoon followed by an anaerobic digester. It was found th at the fungal/anaerobic digester sequential treatment was more effecti ve than the other treatment scheme because the fungus was able to meta bolize the chlorinated organics and attack the chlorolignins thereby m aking them more amenable to degradation by bacteria.