Industrial wastewater re-use: closure of water cycle in the main water consuming industries - the example of paper mills

Paper mill, chemistry, textile and food processing industries are high water consumers. Within the framework of the European project Aquafit4Use, the possibility to close the on-site water loop is studied. The aim is to find new technologies or innovative treatment trains to produce water that is 'fit for use' in the industrial process; an example of a paper mill is given. Laboratory-scale tests on nine technologies were carried out to determine the best suitable treatment train: anaerobic process (already on site) -> aerobic process (already on site) -> Flexible Fibre Filter Module -> softening -> nanofiltration -> evapoconcentration or ozonation on nanofiltration (NF) concentrate. This treatment train is currently compared on site at pilot scale to another treatment train including some modifications on the existing on-site biological treatment: anaerobic process -> softening -> membrane bioreactor -> nanofiltration -> evapoconcentration or ozonation of NF concentrate.