Mezcal is a traditional beverage produced by hand in Mexico, whose elaboration brings with it the generation of vinasses, which are acid wastewater with high concentrations of organic matter (OM), that are commonly discarded into the environment without previous treatment, because vinasses treatment can represent an investment that producers often cannot afford. However, these residues have the potential to be revalued to obtain bio-energy products of economic interest that can benefit these producers.  A strategy that has not been studied with mezcal vinasses is their treatment in a dark fermentation (DF) process, whose purpose is to obtain biogas rich in hydrogen and volatile fatty acids (VFAs) with potential as biofuels. In the present work, the effect of applying 4 reaction times (RT) of 4, 3, 2 and 1 d on the efficiency of COD removal, production of VFAs, as well as the generation and composition of biogas in a process of DF fed with mezcal vinasses, was studied.

The results showed that the reduction of the RT from 4 to 1 d facilitated the control of the DF, preventing the OM from being consumed in a methanogenic process. With which the COD removal decreased from 22 to 9 %, and the biogas production rate improved from 8 to 31 NmL/Lreactorh. In addition, with the RT of 1 d, the highest hydrogen production of 64 ± 21 NmL H2/Lreactor was obtained. However, the RT of 3 d seems to favor the accumulation of VFAs without being consumed, unlike the other RT evaluated.

https://zoom.us/j/96405918066?pwd=MXAzNldJd0Yzdnp4aWs2TTZIY2RYUT09