Effects of white water treatment on the paper properties of mechanical pulp - A laboratory study

The study concluded that efficient removal of extractives from the waters increased tensile index and brightness of the sheets compared to sheets made from unpurified waters. Lipophilic extractives were efficiently removed from peroxidebleached filtrate; resulting in an increase in the tensile index from 20 Nm/g to 30 Nm/g. Removal of extractives was not as critical as the bleaching method regarding the brightness of the sheets. A high concentration of wood substances in the model waters increased the drainage time, especially when using unbleached model waters.