Technical and economic analysis of the combustion of mixed poultry litter/olive pomace pellets for energy recovery

Currently, due to the stringent and explicit European environmental legislation about land spreading of nitrates, the direct land application of the poultry litter (PL) is not anymore the most appropriate disposal technique [European law 1991/676/CEE]. According to the recent European guide lines concerning the smart grids, the generation of electricity and heat from poultry derived wastes based on high-temperature thermal destruction techniques, i.e. combustion, could be a promising local waste management solution. In this work we set out to investigate the technical and the economic feasibility of the combustion of poultry litter blended with olive pomace in a domestic burner (35 kW) initially designed for wood pellets. Flue gas and solid by-products during combustion tests were characterized at varying poultry litter content in the pellets. Compared to the combustion of wood pellets, CO and particulate emissions increased with PL content, whose inorganic fraction was mainly concentrated in the ashes. Under optimized conditions, the burner could be satisfactorily fuelled with pellets containing up to 50% PL by weight.