SECONDARY RECOVERED FUEL (SRF) Secondary Solid Fuels (SRF), partially replacing traditional fossil fuels, are used for environmental and economic purposes with the aim of contributing to the reduction of polluting emissions, including climate-altering gas emissions, to increase the use of sources renewable energy through the sustainable use of biomass contained in waste for energy purposes, and to achieve a higher level of waste recovery, in compliance with the waste treatment hierarchy, in addition to reducing the environmental and economic burdens associated with the disposal of waste in landfills , saving natural resources, reducing dependence on conventional fuels and increasing the certainty of energy supply.