ABSTRACT
The co-evolution of pulp mill process engineering, environmental science, and regulatory discharge requirements which began in the early 1970s continues today. There is a general international convergence in both regulatory parameters and current regulatory issues. Organic/nutrient enrichment and acute toxicity issues are largely resolved. Similarly, the discovery of persistent and bioaccumulating substances in the bleach plant has resulted in the virtual replacement of chlorine gas. Currently, the primary issues are identification of the sources of potential sublethal toxicity in aquatic organisms and the further minimization of aquatic discharges. In Canada, efforts focus on the development of environmental surveillance and laboratory techniques to address sublethal alterations in reproductive hormones. Unmet needs in this approach include the interpretive experience to understand site and ecosystem variability in surveillance data. In the U.S., efforts focus on a revision of effluent command and control regulations. In Nordic geographies, efforts focus on process development to minimize discharge loads and volumes to low levels. Unmet needs for these approaches include the capability to identify, quantify, and then balance environmental benefits against the environmental and social costs of further effluent regulation and minimization.
