ABSTRACT
This paper summarizes three areas of discussion related to future directions for environmental harmonization of pulp mills: (1) the future direction of scientific research, (2) regulatory needs of the future and (3) the technological implications of the scientific findings. The conference made it clear that no more research is needed in the fields of organochlorines such as AOX, chlorophenols and polychlorinated dibenzo-p-dioxins (PCDDs). Instead more research is needed to investigate the environmental exposure and effects of natural wood products and their transformation products. An optimal regulatory strategy was to combine three different tactics: (1) discharge limits, at the end of the effluent pipe, for amounts of pollutants emitted, to attain a reasonable level of industrial practice; (2) site-specific limits, strict enough to eliminate sublethal effects within the aquatic community beyond a mixing zone; and (3) periodic ecological surveys to check the effectiveness of the first two tactics. While it is scientifically unfounded to regulate AOX, the inclusion of COD or DOC under tactic 1 is more controversial. On the one hand there is no direct link between COD/DOC and environmental effects. On the other hand a tight COD/DOC control improves the mill energy balance and may eliminate the compounds in this fraction that cause the remaining weak toxic effects observed from modern bleach plant operations. The reason for the controversy is that many North American pulp mills have invested in chlorine dioxide bleaching instead of oxygen delignification and other techniques that would close up the water streams of the mill. Pollutants measured as COD are lost resources and a tight COD regulation will improve the energy balance and substitute fossil fuel for biofuels. But what are the social costs for society of forcing the development too quickly?
