abstract
- This study presents a Consequential Life Cycle Assessment (CLCA) of a microalgae-based wastewater treatment system for the livestock industry, integrated with a circular bioeconomy approach through biofertilizer production and biogas generation through anaerobic digestion (AD). Three treatment scenarios were evaluated, each employing different combinations of pretreatment technologies, including bioflocculation with chitosan. A scaled-up process model was developed using SuperPro Designer, and the environmental performance was assessed using SimaPro 9.7. Results indicate that scenario with a previous pretreatment using a centrifugation and UV radiation achieved the lowest global warming potential (8129 kg CO¿-eq per ton of dried microalgae), reduced fine particulate matter emissions (38.55 kg PM¿.¿-eq), and required less water consumption (114.29 m3) due to minimal chitosan usage compared to the other scenarios. Sensitivity analysis revealed significant variations in environmental impacts based on microalgae yield and biofertilizer application rates. A 20 % increase in biofertilizer application led to a 27.68 % additional reduction in global warming potential. This research provides compelling evidence for the environmental feasibility and economic viability of large-scale microalgae-based wastewater treatment systems, offering a promising pathway towards sustainable livestock practices and a circular bioeconomy within the agricultural sector. © 2025