Background Cheese manufacture in the Basque region of Spain results in the production of some 25 million litres/yr of the waste by-product whey. Whey is the liquid remaining after milk has been curdled and strained and has a high nutrient content, which can result in environmental problems if it is disposed of inappropriately. However, the high content of serum proteins also gives whey considerable potential to be processed for commercial uses, including in food products, animal feed and biogas. One of the main challenges for achieving this in regions such as the Basque Country of Spain is that much of its production is carried out in small and medium-sized dairies scattered throughout the area. The technical knowledge and high costs of investment needed to deal with this waste product mean that most dairies cannot successfully implement the necessary processes alone. Objectives The 'VALORLACT' project aims to demonstrate an innovative methodology for recovering and transforming whey into valuable products in a hygienic manner. It has been created to design a collection and processing system for whey, including a sufficient number of Basque dairies to make one or more processing plants economically viable. The project will complete an inventory of all whey generated in the project region and characterise its different types, including nutritional and sanitary parameters. It will then define an action plan to valorise the whey completely. It will define methods of storage, treatment, manufacture, transport and logistics and will provide technical detail about operational conditions, facilities and administration to harness a large enough quantity of waste product. The project will identify what infrastructure is needed and construct and operate a pilot plant for whey treatment to obtain whey protein concentrate, lactose and other derivatives. It will also build and start up a pilot plant to extract biogas from the lactose fraction. The project aims to demonstrate and validate under real conditions the valorisation of the resulting products as food, meal for animal feed, and biogas as a form of renewable and clean energy. The project will include technical, economic and environmental feasibility studies, including lifecycle assessment, resulting in a detailed, assessed, demonstrated, validated and agreed procedure to valorise whey generated in the Basque Country. It will also assess integration of the procedure in the Basque Waste Management Plan. The project expects to contribute to improvements in the overall environmental performance of the dairy sector. Expected results Operation of a pilot whey treatment plant with a capacity of 250 litres/hr; Operation of a pilot plant to extract biogas from lactose with a capacity of 1 500 litres/day; Collection and valorisation of more than 80% of whey generated in the area - equivalent to more than 18 million litres/yr (18 000 tonnes/yr) of whey; Production and validation of 5 tonnes of animal feed and at least 100 kg (350 units) of food products; Generation of 6 400 m3 of biogas – offering a reduction of 56 000 kg of CO2-equivalent emissions; Definition and agreement of a system for ongoing revalorisation of whey in the Basque Country; and Definition of the conditions and technology necessary for implementation of the system in other regions. The project will also contribute to enabling further legislation to restrict dumping of whey to water bodies and/or sewage and further enhancements to the overall environment.