REDUCING CHLORINATED ORGANICS, AOX, IN THE BLEACHERY EFFLUENTS OF A TURKISH PULP AND PAPER PLANT

The possibility for reducing the chlorinated organic compounds in the bleacheary effluents of the Turkish pulp and paper industry has been s tudied. Within the experimental work of this study, three different ch lorine dioxide substitutions and three different total chlorine applic ation rates were examined and nine experiments were performed. The AOX formation has been shown to be proportional to the amount of molecula r chlorine consumed during delignification, regardless of whether it i s from chlorine or chlorine dioxide. However, molecular chlorine contr ibutes to AOX formation to a much greater extent. The lowest AOX conce ntrations were achieved when the total available chlorine dosage was l owest (10 kg/ton) and ClO2 substitution level was highest. An increase in the percentage of chlorine dioxide leads to a substantial reductio n in the AOX concentration in the bleachery effluents. A chlorine diox ide substitution of 90%, when the chlorine charge was 40 kg/ton, cause s a 77% decrease in the DC-AOX and a 82% decrease in the EO-AOX. Howev er, as the chlorine dioxide substitution reduced to 10%, the decrease in the the AOX concentration became less and only 51% and 41% reductio ns in DC-AOX and EO-AOX could have been achieved respectively. Copyrig ht (C) 1996 IAWQ.