Water Consumption in Paper Industry – Reduction Capabilities and the Consequences

Water is particularly important substance in papermaking. It plays essential role in fibers transportation, equipment cleaning, lubrication, cooling and in development of a product quality. A tendency to reduce the fresh water consumption in paper production is economically and environmentally justifiable but it must be emphasized that strict closing of water system in paper mill has significant negative impact on several technological operations. High water temperature, as well as increased content of suspended and dissolved solids in water system of a paper machine is examples of major consequences of closing the water loop. As a result, serious problems may cause e.g. paper defects, loss of product quality and problems with run ability of a paper machine. Situation becomes even worse when recycled raw materials are used. Hence, methods of fresh water usage reduction in papermaking are very complex issues and usually depend on the degree of closure. Equilibrium between the advantages and the disadvantages relevant to water consumption restrictions should be established. The acceptable level of water loop closure will depend on the several factors e.g. paper quality required, raw materials used, chemical additives, equipment and staff education.