Wheat Pulp Wastewater from Cereal Starch Production: Treatment & Valorization Using Black Soldier Fly Larvae

The LarWaR process (Larvae for water treatment and resource recovery) has been recently introduced as an innovative biological treatment for high organic content wastewaters, based on the use of Black Soldier Fly (BSF) larvae. The process is capable of simultaneously achieving the efficient removal of organic matter and the recovery of high valuable resources from larval biomass. This experimental thesis investigates the treatability of Wheat Pulp Wastewater (WPW) from cereal starch production by means of LarWaR process. Following a preliminary suitability analysis based on organic content and macronutrient composition, laboratory-scale batch trials were conducted, testing four different organic feeding loads (1, 2, 4 and 8 mgC/larva/day). Daily activities involved monitoring effluent volumes, collecting samples for Total Organic Carbon (TOC) analysis, and periodically measuring larval growth and pupae formation. To evaluate process efficiency and biomass conversion, key parameters were determined: the specific consumption rate v_s , the organic carbon removal efficiency (η), the biomass yield (Y), and the survival rate (SR). The treated effluent was further characterized in terms of COD, BOD₅, and nitrogen forms (TKN, N-NH₃, N_org) to assess overall treatment quality. The results revealed a clear trade-off between treatment performance and larval growth, with removal efficiency decreasing and substrate consumption increasing as the organic load rose, consistent with a Michaelis-Menten-type saturation kinetics. The organic loading rate of 2 mgC/larva/day combined high removal efficiency (92.5%) with the highest larval survival rate (99%), while 4 mgC/larva/day, despite a lower removal efficiency, allowed the required reactor volume to be halved and resulted in grater overall final larval weight . These findings confirm the suitability of wheat pulp wastewater for treatment via the LarWaR process and provide a quantitative basis for the future design and scale-up of the system, depending on the specific treatment priorities.

This experimental thesis focuses on Wheat Pulp Wastewater, a residue from cereal starch production, using Black Soldier Flay Larvae (BSFL). Experimental trials were conducted testing four different organic feeding loads (0.5, 1.0, 1.5, 3.0 mgC/larva/day) at a constant initial larval density. Daily and bi-daily activities involved monitoring effluent volumes, collecting samples for Total Organic Carbon (TOC) analysis, and measuring larval growth. To evaluate the process efficiency and biomass conversion, key parameters were calculated: - Specific consumption rate; - Organic C removal efficiency; - Biomass yield; - Survival rate. The final goal is to verify if the larvae can succesfully treat and crean the wastewater, and to evaluate if the resulting insect biomass can be used for enrgy recovery or other valorization pathways.