The pulp and paper industry Is facing ever-increasing pressures to reduce its environmental pollution, and it is having to comply with more stringent governmental regulations on the discharge of effluents. Any development which can raise the efficiency of wastewater treatment in the paper industry must therefore be welcome. The Kaldnes process, devised in Norway, promises just such a solution. The process is already in operation at mills in Scandinavia, and has now been ordered by an Australian plant. As other paper-producing countries become more environmentally aware, it could become one of the major solutions for the world paper industry＇s effluent discharge problems. In this article Dr Steve Mined presents the results of pilot studies of the Kaldnes process conducted at four pulp and paper mills in Scandinavia.