IN-LINE BIOLOGICAL PROCESS WATER-TREATMENT FOR ZERO DISCHARGE OPERATION AT RECYCLED FIBER BOARD MILLS - COMBINED AEROBIC ANAEROBIC SYSTEM IS DISCUSSED/

Reduction of effluent discharge leads to process water accumulations o f different kinds. These can have a negative impact on the papermaking process as well as on product quality. The article gives an overview of the problems that may occur when operating zero discharge: The caus es and mechanisms, as well as the possibilities for coping with them. One cost effective method that removes almost all organic and inorgani c impurities is combined anaerobic and aerobic treatment. This is demo nstrated in a first full-scale example.