Effluent quality at kraft mills that use complete substitution bleaching

Data on effluent quality were compiled from North American kraft mills with ECF bleach plants. Bleach plant effluents rarely yielded detectable levels of TCDF or of 12 highly substituted chlorinated phenolic compounds. TCDD w as not detected above analytical minimums in any of the 119 samples. Chloro form was commonly detected in the effluents. AOX loadings in biologically t reated effluents tended to be lower at mills with extended and/or oxygen de lignification. Data on dioxin and furan in wastewater treatment residuals s uggested no difference, in terms of toxic equivalents, between mills using conventional delignification and those using oxygen delignification. In reg ard to TCDD/F concentrations, residuals of complete substitution mills are essentially the same as those from municipal wastewater treatment residuals .