Europe is the second world producer of pulp and paper, representing 23% of world production and an annual turnover of 180 billion EUR (1.26% of the European GDP). According to the Confederation of EU Paper Industries (CEPI), Pulp and Paper Industry (PPI) rejects show a great potential as feedstock for the production of high value products in other industries, paper (fibres) or energy conversion. Nowadays, 55% of the rejects are burnt for energy production, land application accounts to 15%, and exploitation of residues in other industries to 10%. 1,65 million of tonnes of rejects generated by the PPI (15% of the total waste), are still disposed to landfills.