To CD or Not to CD, That is the Question, 1991 Pulping Conference Proceedings

Today, environmental issues are mainly consumer driven. The general public is now very concerned about the discharges of chlorinated organics from the pulp and paper industry, and also about the possible occurence of harmful chlorinated compounds in the product itself. Consumer organizations are requiring that AOX-discharges from mills be below the discharge levels laid down by the authorities. In Europe there is a strong pressure to avoid CD-bleaching (bleaching with chlorine gas “C” and chlorine dioxide “D”) as soon as possible.

This paper presents a new fluff pulp from Stora Cell developed in order to meet these new, stringent requirements. It also gives a comprehensive picture of the discharge to water from production of the new pulp. The paper furthermore discusses the chemical differences in effluent composition between low and high AOX levels. Some comments will also be given as to different levels of OX in the product.

The biological effects of the effluents from production of the new pulp have been assessed through comprehensive toxicity testing, using a three-tiered testing scheme. The last step in this assessment consisted of long-term studies in model ecosystems, at low, realistic effluent concentrations. Results from these effect studies are presented, and it is discussed to what extent the discharge parameters currently used in the pulp industry, especially AOX, correlate with measures of environmental impact.

Attention is drawn to the fact that halogenated organics are also naturally made and that these compounds are similar to those found in the bleach plant effluent.