Product based evaluation of pyrolysis of food waste and its digestate

The aim of this work was to assess the energy potential of food waste energy harvesting system (digestion followed by pyrolysis of digestate). Digestate (DFW) with increased calorific content was produced after a commercial one stage anaerobic digestion of the raw food waste (RFW). Separate pyrolysis of RFW and DFW (digestated food waste) distributed 15.7 MJ/kg and 17.2 MJ/kg respectively, among the gas, char and bio-oil, while energy of pyrolysis at 0.72 MJ/kg for RFW and 0.87 MJ/kg for DFW at the heating rate of 10 °C/min to 500 °C. Increase in the digestate specific heat to 2.5 MJ/m3 and its significant ash difference reflects the substrate (RFW) transformation due to biochemical treatment. The thermogravimetric analysis indicated the substrates mass dynamics and stability extent of the treatment products (DFW, RFW500 and DFW500). Generally, transitional energy base products (biogas and bio-oil) are generated through the energy harvesting system (EHS) of food waste, while energy rich solid fuels can be produced through pyrolysis at 500 °C. Thus, the sustainable potential of EHS to widen and broaden recycling capacity of biomass and smartly appropriate its resources are demonstrated to be dependent and pivoted on the adopted treatment method.