Different approaches to sugarcane vinasse use and management in Brazil: A technical, economic, and environmental analysis

Sugarcane ethanol production generates various residues, with vinasse being the most voluminous. Due to its high organic matter, potassium, and sulfate content, improper disposal of vinasse can cause significant environmental impacts. Anaerobic biodigestion and vinasse concentration are promising technologies for managing vinasse effectively and harnessing its properties. This study compares three vinasse management approaches: in natura application, vinasse biodigestion with different biogas uses, and vinasse concentration. To enhance environmental accuracy, methane (CH4) emissions from in natura vinasse transportation channels and fugitive emissions from the biodigestion process-two often overlooked or underestimated emission sources-were considered. Environmental assessments revealed that while most scenarios performed slightly better than the in natura approach, biodigestion scenarios were expected to deliver greater benefits. However, fugitive CH4 emissions significantly influenced the results, highlighting the need to monitor and mitigate these losses to advance the technology economically and environmentally. The vinasse concentration process emerged as a viable alternative, ranking second in cost-effectiveness, just below biodigestion with diesel substitution scenario. These findings emphasize the potential of this approach to balance economic and environmental benefits, explaining its increasing adoption as a large-scale strategy. The economic analysis revealed that the biodigestion with diesel substitution scenario achieved a slightly higher internal rate of return of 15 % compared to the other scenarios. Additionally, the sensitivity analysis showed that carbon credits sales could further enhance economic performance, contributing approximately 6 % to total revenue. Overall, the study demonstrates the promising potential of vinasse concentration and biodigestion as integrated strategies for sustainable sugarcane ethanol production.