Decolorization and treatment of Kokuto-shochu distillery wastewater by the combination treatment involving biodecolorization and biotreatment by Penicillium oxalicum d, physical decolorization by ozonation and treatment by activated sludge.

Kokuto-shochu is a traditional Japanese distilled liquor made from brown sugar. Kokuto-shochu distillery wastewater (KDW) contains high concentrations of organic compounds and brown pigments (called molasses pigments) which are hardly decolorized by general biological wastewater treatment. A fungus, Penicillium oxalicum d, which we isolated in a previous study, decolorizes 47% of the color from KDW without the addition of any nutrients. P. oxalicum d decolorizes KDW by absorbing the pigments into its mycelia. Here we describe a KDW treatment system that combines biodecolorization and biotreatment by P. oxalicum d with treatment by activated sludge and physical decolorization by ozonation. Adding HClO to suppress bacterial growth and replacing fresh seed sludge at regular intervals helped to maintain the dominance and decolorization ability of P. oxalicum d. In a laboratory-scale demonstration, 48 cycles (12 days) achieved a decolorization ratio of 90% and removed more than 97% of dissolved organic carbon (DOC), dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP). A major feature of our system is that it uses only 6% of the water used in an activated sludge-ozonation system.