Causes of high fibre and fines content in sieve water

As the usual mechanical separation processes (sedimentation and filtration via polydisc filters, circular screen thickeners, etc.) are usually hydraulically overloaded, efficient separation of the solids content from the white water can often not be achieved purely mechanically (especially in the production of papers with a high filler content and when using secondary fibers), which is why often additional dissolved air flotation systems or flocculant-supported sedimentaion systems are used.