Bioremediation of cheese processing effluents using Hermetia illucens larvae: Effects of support substrate and larval preparation conditions

This study evaluated the efficiency of Hermetia illucens larvae (black soldier fly larvae, BSFL) on measured chemical oxygen demand (COD) concentration and turbidity in cheese-processing effluents while simultaneously assessing larval performance. The investigation was structured in two phases. In Phase I, three substrates were compared: cheese dairy wastewater (CDW), fresh second cheese whey (FSCW), and fermented second cheese whey (FeSCW), to identify the best-performing substrate among those evaluated for larval bioconversion. FeSCW showed the highest performance, achieving approximately 48% reduction in measured COD concentration, over 93% turbidity reduction, and larval survival close to 97%, although the experimental design did not isolate fermentation as a causal factor or establish increased substrate bioavailability. In Phase II, the individual and combined effects of ABS support (with support, WS; without support, NS) and two larval preparation conditions were evaluated: larvae maintained in clean water without feed for 24 h before exposure (WF) and larvae maintained under standard colony-rearing conditions with access to feed until transfer (NF). The largest reduction in measured COD concentration (54%) was achieved under the WS–NF condition, whereas the highest turbidity reduction (>95%) was observed under the NS–WF condition. The WF preparation condition was associated with higher turbidity reduction than the NF condition, without significant differences in larval growth, survival, or specific growth rate. A significant interaction between ABS support and larval preparation conditions was observed for the reduction in measured COD concentration. Considering the reduction in measured COD concentration and satisfactory larval biological performance, the WS–NF condition showed the best performance among the evaluated conditions. The results indicate that BSFL-based entomoremediation can contribute to partial reductions in measured COD concentration and turbidity in cheese-processing effluents under laboratory conditions. Among the evaluated substrates, FeSCW showed the best performance under the tested operational conditions, supporting further investigation of BSFL as a possible pretreatment step within integrated cheese-processing wastewater management systems.