effects of chlorination conditions on the AOX and chlorinated phenol content of kraft bleach plant wastewaters

• Published in: Water science and technology 1991-01, Vol.24 (3/4), p.55-63
• Main Authors: McFarlane, P.N, Allison, R.W, Clark, T.A, Mackie, K.L
• Format: Article
• Language: English
• Subjects: adsorbable organic halide; Bleaches; Bleaching; bleaching oxygen delignified kraft pulp; change; Chlorination; Chlorine; Chlorine compounds; Chlorine dioxide; Chlorophenol; chlorophenolic compounds; Experimental design; phenolic compounds; Phenols; Pinus radiata; pulp and paper mill effluents; Pulp mill effluents; technology; wastewater
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.1991.0462

A central composite experimental design was used to develop models of the yields of Adsorbable Organic Halide (AOX) and chlorophenolic compounds in wastewaters produced by bleaching oxygen delignified kraft pulps. The following five variables were used to control the bleaching conditions: total available chlorine, chlorine dioxide substitution, incoming kappa number, chlorination time and temperature. The total available chlorine and the chlorine dioxide substitution were the most important parameters in all the models developed. The yields (g. tonne super(-1)) of AOX and total chlorophenolic compounds increased linearly with increasing total chlorine application. Elevating the level of chlorine dioxide substitution caused the yield of AOX to decrease linearly while the yield of total chlorophenols diminished in a non-linear manner. Increasing the level of chlorine dioxide substitution at a given total chlorine application is an effective means of reducing the emissions of both AOX and chlorinated phenols.