High-performance solid recovered fuel from food waste digestate and bamboo powder: Mechanistic insights into structural reinforcement and combustion stability

Food waste digestate (FD), a byproduct of anaerobic digestion, poses resource potential but also challenges due to high moisture, low calorific value, and high ash content, which limit direct incineration. This study investigated co-pelletization of FD with bamboo powder (BP), a high-calorific biomass with binding capacity, to produce stable, energy-dense fuel. FD and BP were blended at ratios from 90:10 to 50:50 and pelletized at 120 °C and 120 MPa. BP addition enhanced pellet structure, with compressive strength increased by >120% and abrasion loss dropping below 1% at FD/BP = 5:5, while storage stability improved. The higher heating value (HHV) increased by 30.3% to 13.3 MJ/kg, and thermogravimetric analysis showed synergistic effects: ignition and burnout temperatures fell to 277 °C and 542 °C, and the combustion index reached 5.07 × 10−7. Gas analysis indicated slightly higher CO2 release but more complete CO oxidation and reduced NO emissions at higher BP levels. Ash characterization confirmed enhanced slagging resistance via higher Si/Al and lower base-to-acid ratios, yielding fusion temperatures >1300 °C. Overall, FD/BP co-pelletization converts digestate into durable, energy-rich fuel with improved combustion and slagging resistance, offering a promising route for waste valorization, subject to further pilot-scale validation and TEA/LCA evaluation.