Why is water used in paper industry

Water reuse in the paper and pulp industry

Overview of water reuse in various industries

Water reuse in the paper and pulp industry

Due to environmental protection requirements and stricter legislation, the pulp and paper industry is forced to reduce its water consumption. Usually the wastewater from a paper mill is treated biologically. The wastewater quality achieved in this way is sufficient for the discharge of the treated wastewater, but not good enough for the water to be reused as process water.

Membrane filtration is a treatment variant for the production of process water. Usually microfiltration (MF), ultrafiltration (UF) and nanofiltration membranes (NF) are used. Ceramic membranes have only recently come into use. The advantage of these membranes is that they are easy to clean using the backwash principle in contrast to activated carbon filters. Backwashing periodically reverses the permeate flow in order to increase the flux and remove deposits from the membrane surface. Lower flux rates and greater fouling were found in the acidic pH range than in the neutral pH range.[1]
This can be explained by a lack of electrostatic repulsive forces between the membrane and the dissolved substances in the water in the acidic pH range. In the neutral pH range, on the other hand, electrostatic repulsion forces occur, which results in better permeability.[2]

Another application is the membrane bioreactor (MBR). This technique is used, among other things, for the treatment of waste water from the bleaching process. The purified water can be fed back into the machining process.[3]

[1] Niina Laitinen, Antero Luonsi, Erkki Levänen, Marianne Nyström, Effect of backflushing conditions on ultrafiltration of board industry wastewaters with ceramic membranes. Tampere, Finland 2001

[2] Jutta Nuortlla-Joklnen, Anne Kuparine, Marianne Nyström, Tailoring an economical membrane process for internal purification in the paper industry. Lappeenranta, Finland, June 1998

[3] R. Tenno, H. Paulapuro, Removal of dissolved organic compounds from paper machine whitewater by membrane bioreactors: a comparative analysis. Espoo, Finland 1999

Information on water reuse in the food, brewery and textile industries,
Water disinfection and reuse in greenhouses
Information on water treatment and recycling of oily wastewater
Water reuse in poultry farming
Use of domestic sewage for agricultural purposes

If you know of other interesting and up-to-date books, reports, articles or publications on the subject of water reuse in the paper industry, please let us know so that we can add case studies to the general overview.