A PROCESS FOR CONCENTRATING SOLUBLE AND COLLOIDAL SUBSTANCESIN PROCESS WATERS

摘要

The invention relates to a process for enhancing the concentration of the fibre derived dissolved and colloidal substances in process water that comes from mechanical pulping. According to the invention, process water is treate d with enzyme preparations that have an effect on carbohydrates and that conta in mannanase and/or endoglucanase, in particular, which break down the soluble carbohydrate polymers contained by the process water into low molecular weig ht oligosaccharides. The treatment prevents an increase in viscosity so that process water can be concentrated into a high dry content, or the treatment can be used to lower the viscosity of previously concentrated process water to facilitate after-treatment.