Dynamics of trace metals in vinasse anaerobic digestion: Effect of Ba supplementation

Abstract

Considering the concept of the biorefinery in ethanol production plants, the two-phase anaerobic systems is an alternative for H2 and CH4 from its sub-product, vinasse. Especially in two-phase anaerobic systems, there is the possibility to adjust each reactor, acidogenic and methanogenic, to the specific needs of the desired microbial consortium, aiming to optimize the H2 in the first stage and CH4 on the following reactor. Trace metals (TM) are essential to establish the appropriate conditions for several microorganisms contained in the anaerobic systems to growing and performing the catabolic activities, once the TMs are involved in enzymes and co-factors composition and activities that take place in metabolic pathways of H2 and CH4 production. In this regard, the dynamic of TM and their bioavailability in anaerobic systems might be an important tool to improve the performance of these systems. Therefore, it is proposed to carry out a two-phase anaerobic system to the thermophilic treatment of vinasse, using a structured bed reactor, adding Ba and monitoring the TM dynamics. The aiming is to precipitate Ba with the dissolved CO2 as BaCO3, inhibiting the deployment of homoacetogenesis, and to precipitate Ba with sulfate to avoid the competition between methanogenic archaeas and sulfate-reducing bacteria, as well as to avoid the precipitation of essentials TM.