The fate of metals in forest industry wastewater treatment systems

The capture/removal of a range of metals was estimated for a number of pulp and paper wastewater treatment systems. Both long-term wastewater data and accumulated sludge data were examined. Only copper and lead were effectively captured (greater than 50%) by all sites and estimate methods. Zinc capture exceeded 50% in all but one case. Qualitatively, iron, aluminium, cadmium, and cobalt were usually captured to a significant extent. The sludge inventory-based approach and the wastewater system inlet-outlet approach gave reasonably similar capture estimates.