Comparison and Evaluation of Methods for the Determination of AOX, 1992 Environmental Conference Proceedings

Numerous different procedures have evolved in Scandinavia, Canada and the U.S. for the determination of AOX in pulp and paper industry wastewaters. Of these, Standard Methods (16th Edition) Method 506, SCAN-W 9:89, ISO/DIS 9562 and/or Draft EPA Method 1650 have been incorporated into NPDES permits and constitute the focus of this paper. The procedures allow different degrees of flexibility in the preparation of samples for pyrolysis and microcoulometric determination. The differences and similarities of the procedures are summarized and the results of selected studies assessing the significance of the differences are presented. Another significant variation in the procedures revolves around the means used to quality control the procedure. Each method adopts a slightly different means of establishing instrument performance, determining adsorption breakthrough, controlling reproducibility or accuracy, and documenting carbon quality. The QA/QC schemes used in the different methods are summarized and compared.