Investigation of the impacts of sulfate reduction in Hydrogenogenic activity during the thermophilic fermentation of sugarcane vinasse

Abstract

One of the biggest challenges of the Brazilian sugar-energy sector is the management of vinasse from the ethanol production process. Recently, technologies based on the sustainability of this process have been developed where it is possible to simultaneously treat vinasse and recover energy in the form of biogas to supply energy in the plant itself. However, the high concentrations of sulfate commonly found in vinasse end up directly affecting the metabolic routes of anaerobic digestion and consequently the production of biogas. In addition to significantly reducing the generation of methane, sulfate also ends up contaminating this biogas with sulfide gas, which can even be corrosive. Purification of biogas has a very high cost making the process financially unfeasible. Thus, through this project and studies carried out at the Laboratory of Biological Processes (LPB) of the São Carlos School of Engineering of the University of São Paulo (EESC/USP), including by the author himself, we seek to broaden the understanding of reactors sulfetogenic-acidogenic and the impact of sulfate reduction on acidogenesis, specifically on biohydrogen production, since the studies carried out have not yet indicated the real impact of sulfidogenesis on hydrogenogenic activity. Thus, it is expected to use acidogenesis as a strategic step for the removal of sulfate. The experiments will be conducted in batch reactors and will follow an experimental plan, from which it is also intended to establish operational conditions that favor sulfidogenesis.