International Paper Company

Christopher P Hung

Caifang F Yin

Jasper H Field

Hugh P Gallagher

The invention described in the specification relates to a process and apparatus for reducing AOX, COD and color bodies from the filtrate streams generated by a kraft pulp bleaching sequence. The method involves vigorously mixing an F.sub.D filtrate with an F.sub.E filtrate to form a filtrate mixture and treating the filtrate mixture with a coagulating compound, a flocculating compound and recycled foam concentrate. After chemically treating the filtrate mixture, the mixture is foamed with air in order to capture floc which formed in the mixture. Concentration of the foam and recycle of the foam to the filtrate mixture has been found to significantly increase the concentration of and reduce the amount of solids generated in the treatment system.

Foam separation method for reducing AOX, COD, and color bodies of kraft

The invention described in the specification relates to a process and apparatus for the reduction of adsorbable organic halide (AOX), chemical oxygen demand (COD) and color bodies from the filtrates generated in a chlorine compound-containing pulp bleaching sequence. The method involves vigorously and intensely mixing certain pulp bleaching filtrates in order to lower the AOX content of the filtrate and the use of a peroxy compound and a ferrous salt catalyst to treat a combined filtrate streams thereby significantly reducing the level of AOX, COD and color in the effluent leaving the pulp bleaching plant.

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Highland Mills, NY, United States of America

Christopher P Hung