Environmental Performance of Hermetia illucens Bioconversion in a Medium-Scale Mass Rearing System to Valorize Agri-Food Industrial Residue

Valorizing agri-food waste through black soldier fly larvae (BSFL) bioconversion offers a promising path to enhance circular and sustainable food systems. This study used attributional Life Cycle Assessment (LCA) to evaluate the environmental performance of BSFL reared on six agro-industrial residue diets: tomato, pea, onion, chickpea, wheat, and liquid digestate. The Environmental Footprint 3.1 method was used to assess multiple impact categories. The rearing trials were conducted in a dedicated pilot plant (13.5 m × 2.5 m × 2.7 m) that can treat about 1.58 t of residue per cycle. From the results, BSFL biomass yields were similar across diets, with 12–15% bioconversion and 70–85% substrate reduction. BSFL protein had higher impacts than fishmeal and pea protein but was comparable to soybean meal. BSFL lipids had greater impacts than rapeseed, palm, and sunflower oils yet were similar to soybean oil for bioenergy from fat. Electricity use for climate control was the main hotspot (~85%). Scenario analysis showed that using residual heat for climate control and scaling up via optimization could cut impacts by over 80%. The findings demonstrate the potential for producing BSFL on a medium-to-large scale to enhance circularity in the agri-food sector.