Reduction of Pulp and Paper Industry Effluent Loading

Abstract

The pulp and paper industry consumes large volumes of water i.e. 10-300 m3/t of product. The most important measure in reducing the pollution charge is a reduction in water consumption. Thereafter, efficient and more easily controllable methods can be used for the treatment of lower volume, more concentrated and warmer wastewaters. Application of medium consistency techniques in production, water recirculation, and more efficient use of wood are pushing development in this direction. It is clear however, that these development trends will undergo certain practical limitations governed by the actual production process. The trends in production favour the utilization of anaerobic techniques in wastewater treatment. Both the purification efficiency and the economy of the treatment system can be improved as seen from the examples in this paper. However, the conventional aerobic treatment is under continuous development and it will be applied as a completing stage of anaerobic treatment. Modifications of the activated sludge process can be applied especially for rather dilute composite pulp mill effluents as presented in this paper.