Overview of AOX Regulations and Reduction Strategies, 1993 Pulping Conference Proceedings

AOX (adsorbable organic halides) is a catch-all term that encompasses chlorinated organic compounds commonly generated in chlorine-containing bleach processes. While not all AOX compounds are harmful to health or the environment, a number of them have been determined to be so. Rather than single out the harmful constituents of AOX for regulatory purposes, regulatory agencies in Canada and Scandinavian countries have used AOX as the measure by which to set limits on effluent discharges. The appropriateness of AOX as the measure for effluent regulations is now being questioned. The US EPA, which is currently in the process of developing effluent guidelines, is taking a hard look as to which is the most appropriate and representative measure for setting discharge limits on pulp mill effluents.

Such regulations have forced the pulp and paper industry in Europe and Canada, and will no doubt force the industry in the US, to reduce AOX discharges through a combination of process modifications and effluent treatment technologies.

This paper reviews and discusses the status of regulations on AOX in Canada, Scandinavia and the US, and process technology and effluent treatment options to reduce AOX discharges.