Produção metanogênica a partir da biomassa residual da macrófita aquática Eichhornia crassipes

Abstract

The predictability of fossil fuel reserves depletion and the environmental consequences stemming from their intermittent use have triggered new perspectives for energy generation to ensure sustainability. In this context, one of the main challenges is to ensure energy generation sustainably. In view of this, methane production through biological processes emerges as an alternative to replace fuels derived from conventional energy sources. However, the effective potential for biogas generation is linked to the type of waste utilized. Thus, the use of aquatic macrophytes, which exhibit high growth rates due to eutrophication processes, resulting in decreased dissolved oxygen levels, fish mortality, loss of biodiversity, thereby generating abundant biomass susceptible to biodegradation, is noteworthy. In light of this, this study aimed to investigate solutions for the treatment and energy utilization of aquatic biomass, aiming to contribute to environmental and energy sustainability. To this end, 8 batch digesters were employed in the anaerobic digestion of macrophytes, using a 22 factorial design to evaluate the effects of biomass and salinity of the medium. As a result, after 37 days of anaerobic fermentation, quantitative results showed that all reactors produced biogas, indicating the effectiveness of the process in converting aquatic macrophyte biomass into energy, with an average production of 353.7 mL of CH4. It is noteworthy that reactor R2, containing the highest amount of biomass and the lowest salinity, presented the highest average, reaching 408.04 mL of CH4. Meanwhile, reactor R4, distinguished by its high NaCl concentration, corresponding to 0.17 g.L-1, achieved the lowest CH4 production, around 210.47 mL of CH4. Therefore, it was concluded that high salinity concentrations hinder methanogenic production, emerging as a critical element to optimize the efficiency and effectiveness of reactors under various conditions.