Characteristics of dissolved organic material in total chlorine free bleach plant and laboratory effluents

The dissolved organic material present in totally chlorine free (TCF) pulp mill bleaching effluents and in their laboratory made counterparts was char acterized using chemical and chromatographic analysis. Special attention wa s given to analysis of material originating from lignin and carbohydrate. W ith the exception of the Pt laboratory effluent, the BOD7, COD and TOC load s and the content of aromatic lignin in the effluents, were higher in the m ill effluents. After oxygen stages, the content of monomeric acidic phenols and aromatic acids in the effluents was very low. The highest amount of ca rbohydrates was found dissolved in the first P stage mill effluent. The ave rage molar mass of UV-absorbing material was lowest in ozone effluents. Car bohydrates were determined as monosaccharides after acid hydrolysis. Xylan was the main carbohydrate component in most effluents, and after ultrafiltr ation more xylose was found in fractions over 10000 NMM. Ozone effluents we re rich in arabinose, which was mostly found in fractions below 10000 NMM. Most of the mannose and galactose that dissolved in the first alkaline pero xide stage effluents was found in fractions over 10000 NMM. (C) 1999 Publis hed by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.