Avaliação experimental da produção de biometano a partir de macrófitas aquáticas (Eichhornia crassipes) oriundas do Baixo São Francisco

Abstract

The excessive proliferation of aquatic macrophytes in the Lower São Francisco region has led to a series of adverse implications for both the local economy and the surrounding marine ecosystem. These negative effects include, among other aspects, a reduction in fishing activity, indications of contamination by thermotolerant coliforms, decreased levels of dissolved oxygen in the water, and a significant loss of biodiversity. In this context, approaches based on chemical, enzymatic, and biotechnological processes emerge as potential strategies to mitigate the impact of these macrophytes and promote the conversion of their residues into value-added products. Therefore, the present study aims to identify an appropriate destination for residual macrophytes, seeking not only ecosystem rehabilitation through detoxification but also the sustainable production of renewable energy. Thus, a methodological approach was implemented using the Central Composite Rotational Design (CCRD) statistical technique to evaluate the combined influence of substrate mass concentration and medium salinity on biomethane yield through the anaerobic fermentation process. In the initial stage of the study, a methane yield of 297.07 ± 18.87 mL/g VS was obtained for a substrate concentration of 5 g/100 mL and 0 g/L medium salinity. In the second stage, through CCRD, it was observed that the linear and quadratic models were not representative, presenting explained variation percentages of 64.54% and 69.50%, respectively. The highest methane yield was 113.6 mL/g VS, found in the reactor with a substrate concentration of 10 g/100 mL and medium salinity of 0 g/L.