Waste water bleaching effluents

Environmental applications of HRP include immunoassays for pesticide detection and the development of methods for waste water treatment and detoxification. Examples of the latter include removal of aromatic amines and phenols from waste water (280-282), and phenols from coal-conversion waters (283). A method for the removal of chlorinated phenols from waste water using immobilised HRP has been reported (284). Additives such as polyethylene glycol can increase the efficiency of peroxidase-catalyzed polymerization and precipitation of substituted phenols and amines in waste or drinking water (285). The enzyme can also be used in biobleaching reactions, for example, in the decolorization of bleach plant effluent (286). 

Hauptmann, E.G. et al., Strategies for treatment mixtures of bleach plant effluents and waste water treatment sludges by supercritical water oxidation, preprints of papers to be presented at the annual meeting, 80(B), B71-B77, 1994. 

CDDs/CDFs, specifically 2,3,7,8-TCDD and 2,3,7,8-TCDF, are also present in effluent and sludges from pulp and paper mills that employ the bleached kraft process (Clement et al. 1989 EPA 1991b Swanson et al. 1988). 2,3,7,8-TCDD was detected in 7 of 9 bleached pulps at concentrations ranging from not detected (<1 ppt) to 51 ppt (median 4.9 ppt mean 13 ppt) (Amendola et al. 1989). It was also detected in waste waters from 4 of 5 paper mills at levels ranging from not detected (<0.006 ppt) to 3.6 ppt (Amendola et al. 1989). 

Saski, E.K., J.K. Jokela, and M.S. Salkinoja-Salonen. 1996a. Biodegradability of different size classes of bleached kraft mill effluent organic halogens during waste-water treatment and in lake environments pp. 179-193. In Environmental Fate and Effects of Pulp and Paper Mill Effluents (Eds. M.R. Servos, K.R. Munlittrick, J.H. Carey, and G.J. van der Kraak). St. Lucie Press, Delray Beach, FL. 

Figure 25. The sequential photocatalytic treatment of the effluent previously treated with Trametes Versicolor. The irradiation time used was 60 min. Reprinted from, Aura M. Pedroza, Rodolfo Mosqueda, Nicolas Alonso-Vante and Refugio Rodriguez-Vazquez, Sequential treatment via Trametes versicolor and UV/Ti02/RuxSey to reduce contaminants in waste water resulting from the bleaching process during paper production, Chemosphere 67 (2007) 793, Copyright (2007), with permission from Elsevier.

The effluents from the bleaching process contain chlorinated organic compounds and cannot be disposed of by combustion with the spent cooking liquor. It pollutes the waste water stream with its oxygen demand and its toxic and genotoxic effects, it may even contain polychlorinated dibenzo-ftirans and dibenzo-p-dioxins in small concentrations. The stability of the chloro-organic compounds inaeases its biological and environmental persistence and this increases the tendency to bioconcentration in... 

Donors of appropriate redox potential to react with holes at the anatase surface include organic acids, carbohydrates, fats, CN, and halides 2 ). (The cyanide reaction has been studied for its utility in treatment of the waste streams from Hold mininK operations in the Canadian Northwest Territories.) More immediately releyant to natural water is the observation that an anatase slurry could effect the decoloration of a chlorinated bleach plant effluent. A sample of amber colour, pH = 1.8, and low residual chlorine was irradiated in the presence of 0.5% (wt) anatase with li((ht of 350 nm for periods up to 18 hr. The optical absorbance decreased by half in 1080 min. Small amounts of chloride and formaldehyde were detected ( ). This reaction may provide a precedent for observation of a relation between photobleachinK of humics in water and metal ions. If so, we are brouj ht to the question of the reactivity of colloidal iron oxides. 

Uses Defoamer in aq. systems, mill effluent and waste treatment systems, kraft pulpmill screening and bleaching operations, papennaking systems, food pkg. Properties Tan oily liq. water-disp. dens. 0.864 kg/l 100% cone. 

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