Comparative Performance of Biosorption Pretreatments for Vinasse Phytoremediation Using Salvinia minima

Sugarcane vinasse is a liquid waste generated during bioethanol production. It is characterized by high organic load, acidity, elevated salinity, and recalcitrant compounds, including soluble phenolic compounds and melanoidins, which can hinder its treatment and limit biological processes. This study evaluated batch and fixed-bed column biosorption as pretreatments coupled with phytoremediation using Salvinia minima at laboratory scale. System performance was evaluated based on changes in pH, electrical conductivity (EC), dissolved oxygen (DO), chemical oxygen demand (COD), true color, soluble phenolic compounds (SPCs), and the non-dialyzable melanoidin fraction. Plant physiological responses were evaluated by measuring hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. Following phytoremediation, vinasse pretreated by fixed-bed column biosorption showed greater removal of COD, SPCs, true color, and the non-dialyzable melanoidin fraction. Plants exposed to column-pretreated vinasse also showed lower H2O2 and MDA contents. In contrast, batch-pretreated vinasse adjusted to pH 6 showed an increase in the non-dialyzable melanoidin fraction after phytoremediation, suggesting structural modifications of Maillard reaction-derived compounds rather than their removal. The results indicate that the physicochemical changes occurring during biosorption improved the conditions of sugarcane vinasse for the growth of *S. minima*. Under the conditions evaluated in this study, fixed-bed column biosorption followed by phytoremediation proved to be a more suitable treatment than batch biosorption followed by phytoremediation for the integrated treatment of sugarcane vinasse.