Water use in the pulp and paper industry is very significant, and the U.S. pulp and paper industries as well as other processing industries are actively pursuing water conservation and pollution prevention by in-process recycling of water. Bleach plant effluent is a large portion of the water discharged from a typical bleached kraft pulp mill. The recycling of bleach plant effluents to the kraft recovery cycle is widely regarded as an approach to low effluent bleached kraft pulp production. The focus of this work has been on developing an electrodialysis process for recycling the acidic bleach plant effluent of bleached Kraft pulp mills. Electrodialysis is uniquely suited as a selective kidney to remove non-process elements (NPEs) from bleach plant effluent before they reach the chemical recovery cycle. Using electrodialysis for selective NPE removal can prevent the problems caused by accumulation of inorganic NPEs in the pulping cycle and recovery boiler. In this work, acidic bleach plant filtrates from three mills using different bleaching sequences based on chlorine dioxide were characterized. The analyses showed no fundamental differences in the inorganic NPE composition or other characteristics among these filtrates. The majority of total dissolved solids in the effluents were found to be …

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