Abstract: A process for the removal of dispersed contaminants less dense than water from pulp and paper mill process liquids, comprises passing the liquid through a centrifuge and collecting the contaminants as a less dense fraction. The application of this invention to paper industry process liquids provides a means of removing a significant fraction of the wood resin and wood resin soaps from the process stream, thus enabling (1) a greater extent of reuse of filtrates and, hence, less effluents from mills, and (2) fewer problems from wood resin, such as deposit formation, loss of strength of product, and contamination of product with dirt particles.