Merits of ozonation and catalytic ozonation pre-treatment in the algal treatment of pulp and paper mill effluents

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2006.10.020 Byline: I. Akmehmet BalcioAlu (a), E. Tarlan (b), C. Kivilcimdan (c), M. Turker Sacan (a) Keywords: Algal treatment; Catalytic ozonation; CEH bleaching; Integrated treatment; Kraft pulp; Toxicity Abstract: Since the performance of algal treatment for pulp mill effluent decreases with increasing color intensity and AOX content, which mainly originate from the chlorine bleaching of Kraft pulp, the separated CEH bleaching effluent was pre-treated by both the conventional and the heterogeneous catalytic ozonation processes. An increase in the BOD.sub.5/COD ratio from 0.11 to 0.28 and 87% color abatement in terms of Pt-Co were achieved by catalytic ozonation, which had the best treatment performance. Biodegradability enhancement of the CEH effluent correlated well with a decrease in toxicity, high-molecular-weight-compound content, and AOX abatement. By the pre-treatment of the CEH bleaching effluent, the overall efficiencies of algal treatment of the combined pulp mill effluent in terms of the fractional removal of COD and color were increased from 76% and 53% to 86-90% and 96-99%, respectively. Effects of both the conventional and the catalytic ozonation pre-treatments on subsequent biological treatment were close to each other and they reduced the filling period of the Sequential Batch Reactor (SBR) cycle from 8 to 5 days. Author Affiliation: (a) BoAazici University, Institute of Environmental Sciences, 34342 Bebek-Istanbul, Turkey (b) Faculty of Engineering and Architecture, Department of Environmental Engineering, Selcuk University, 42075 Kampus-Konya, Turkey (c) Department of Environmental Engineering, Middle East Technical University, 06531 Ankara, Turkey Article History: Received 21 March 2006; Revised 19 October 2006; Accepted 31 October 2006