Sugar-cellulose composites.: VI.: Economic evaluation of lactose production from cheese whey for use in paper

Previous papers in this series have shown that a portion of the cellulose fibres in paper can be replaced by lactose without significant changes in the physical properties of the paper. Lactose will only be used to substitute up to 10% of cellulose in paper-making if it is available in quantity at a price less than that of the fibres replaced. Cheese is produced worldwide in large quantities, and its by-product, whey, is mainly dried or, in some cases, fractionated to produce lactose and whey protein concentrate (WPC). Lactose obtained from cheese whey for this application does not need to fulfil FDA or EU requirements. Hence its manufacture is cheaper than for edible grade lactose. Furthcrmore, it is not necessary to dry the cellulose substitute to minimise the transportation cost if the lactose fractionation plant is located close to the paper-mill. An analytical case study has been developed for the industrial environment existing in Asturias (Spain), where seven plants producing more than 400 000 t year (1) of cheese whey, with an annual growth of 3%, and a 150 000 t year (1) paper-mill are located within a circular area of 80 km radius. This analysis has been extended to different plant capacities to allow its application to other locations with similar characteristics. (C) 2002 Society of Chemical Industry.