Most of the current waste streams generated by the Pulp & Paper industry (PPI) are currently disposed to landfills or burnt for energy production. Inorganic wastes are basically used as cement raw material and to a lesser extent as soil amendment in forestry applications. These solutions have a low added value and are dependent on the existence of cement kilns and acid soils in the vicinity of the mills, reducing their potential valorisation. Although there is extensive academic research on the waste valorisation to enhance the utilization of paper mill waste streams, there is still a lack of alternatives proved at real scale under operational conditions.