ABSTRACT
MARIANNE NYSTRÖM, JUTTA NUORTILA-JOKINEN AND MIKA MÄNTTÄRI
Pulp and paper effluents contain invariable amounts of different kinds of substances, some of them originating from the wood and others from the pulping or paper-making process (Table 1). The substances are of varying size, charge and hydrophilicity. In paper making most worries are focused on the pitch-forming substances, which can easily
form specks both on the paper and on the stainless steel in the equip ment. Ions of varying kind can also be of concern, multivalent ions because they harden the water and can form scaling on the equipment, monovalent ions, again like chloride, can be a serious problem if corro sion takes place. Today, when the paper mills get gradually closed water systems, accumulation of these types of substances, bacteria or saccharides could be a problem.
