Methane Fermentation of Sulfite Pulp Mill Waste Water

Abstract

Lately the methane fermentation process has captured a great deal of interest as one of the new methods of generating energy. This new method was first applied with pulp and paper waste water in our mill. Our mill has successfully utilized evaporator condensate of spent sulfite liquor in this process.
The process produces 15, 00017, 000 Nm³gas/day. At the same time, as a result of this treatment, 23 ton CODcr/day, 6 ton COD_Mn/day, and 14 ton BOD₅/day are removed from the waste water. The production cost of the gas equals the price of oil, if they are compared based on heat value. Sedimentation and the activated sludge processes, which are currently the common methods of waste water treatment in our industry, consume considerable energy. Our method of environmental protection requires less energy than the other methods. Furthermore, it becomes a source of new energy.
The present waste water treatment may be replaced by the methane fermentation process in the near future.