This study concentrated on the biological treatment and post-ozonation of mature eucalypt kraft bleachery effluents. The objectives were to optimise reduction of priority pollutants such as AOX, chlorate, high molecular weight chromophores and toxicity while maintaining high COD/BOD removals. Biological treatment was adequately modelled with Monod kinetics, using biodegradable COD. Sludge yields were of the order 0.76 g biomass/g BCOD. Treatment was most effective (70% total COD reduction and 95% BOD5 reduction) with sludge ages over 20 days and F/M ratios 0.2-0.3. Biological treatment did not reduce total AOX nor colour but reduced chlorate by 63% in preliminary trials. A fungal isolate, Aspergillus.p2 reduced colour by 54% when supplemented with glucose. Ozonation as a tertiary treatment reduced AOX by 60% and colour decrease followed first-order kinetics with respect to ozone consumption.
Treatment of Bleachery Effluents from Kraft Mills Pulping Mature Eucalypts
B. H. Boyden, X. Z. Li, T. J. Schulz, O. Hijazin, P. Peiris, J. Bavor; Treatment of Bleachery Effluents from Kraft Mills Pulping Mature Eucalypts. Water Sci Technol 1 March 1994; 29 (5-6): 247–258. doi: https://doi.org/10.2166/wst.1994.0719
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