Microalgae Grown in Hydroponic Greenhouse Wastewater Towards Biofuels: An Environmental Assessment

This study conducts a life cycle assessment (LCA) of a microalgae-based biorefinery producing biofuels, using a well-to-tank approach. Microalgae were cultivated using greenhouse wastewater, while the extracted lipids were converted to biofuels via catalytic hydrotreatment. Experimental data supported an Aspen Plus model to generate inventory data for the LCA. The assessment incorporated multiple environmental metrics, including global warming potential (GWP), net energy ratio (NER) etc., under variant energy sources scenarios. Results show a low GWP (0.86 kg CO2-eq/MJ) and a NER (3.7), indicating favorable environmental performance, while the downstream processes were identified as the most energy-intensive. Sensitivity analysis highlighted the critical role of energy sources, with renewable energy improving the sustainability compared to fossil-based inputs. Overall, the results support the viability of wastewater-grown microalgae for sustainable biofuel production, particularly when integrated with low-impact energy sources.